Myelin sheaths around axons allow saltatory conduction, where action potentials "jump" from one node of Ranvier to the next. This increases conduction velocity and is more energy efficient than action potentials propagating along the entire length of the axon. At synapses, the gap between neurons is bridged by neurotransmitters releasing from the presynaptic axon and signaling to the postsynaptic dendrite of the next neuron.
The document discusses the structure and function of chemical synapses. It begins by defining a synapse as the junction between two nerve cells. It then describes the key anatomical components of a chemical synapse, including the presynaptic knob, synaptic cleft, and postsynaptic membrane. It explains the process of neurotransmission, including the release of neurotransmitters into the synaptic cleft, their binding to receptors on the postsynaptic membrane, and the resulting postsynaptic potentials. The document also discusses inhibition at synapses, the properties of synaptic transmission, and examples of neurotransmitters.
This document discusses the generation and propagation of action potentials in neurons. It notes that neurons respond to stimuli by producing either local, non-propagated potentials or propagated action potentials. Action potentials are generated when voltage-gated sodium channels open in response to depolarization, allowing sodium ions to rush in and briefly reverse the membrane potential. This wave of depolarization then propagates down the axon by electrotonic conduction. The document outlines the changes in membrane permeability and potential during an action potential and describes how action potentials conduct in either direction along the axon.
This document provides an overview of synapses, including their definition, structure, function, types of transmission (electrical vs. chemical), neurotransmitters, and various properties like synaptic delay, fatigue, summation, and more. It discusses excitatory and inhibitory neurotransmitters and how convergence and divergence allow signals to be dispersed or combined. Clinical implications are that problems with synaptic transmission can cause diseases like Parkinson's and Alzheimer's.
Nervous system forms an interconnecting fibers of communication network.
In the ‘hard-wiring’ of the nerves, the signals travel in the form of a flow of electrical current called nerve impulses.
The stimulus-response reactions afford internal constancy in the face of environmental changes.
The resting membrane potential (RMP) refers to the stable voltage difference between the inside and outside of a cell membrane when the cell is not actively transmitting signals. The RMP results from selective permeability of ions like potassium and sodium across the membrane. At rest, the neuron's RMP is approximately -70mV due to higher intracellular potassium concentration creating a diffusion potential of -94mV, and lower intracellular sodium contributing +61mV. Additional contribution from the sodium-potassium pump, which actively transports ions against their gradients, results in the overall RMP of -90mV in neurons.
this ppt shares what synapses are and how information of one neuron is transmitted to other through the synapses. it also includes the properties and plasticity of synaptic transmission
Nerve fibers can be classified based on their structure and distribution. There are two main types - myelinated and unmyelinated fibers. Nerve fibers also include somatic and autonomic fibers. Somatic fibers innervate skeletal muscles and the neurotransmitter is acetylcholine, leading to muscle excitation or central inhibition. Autonomic fibers innervate smooth, cardiac muscles and glands to maintain homeostasis, causing excitation or inhibition. Important properties of nerve fibers include excitability, conductivity, unfatigability, refractory periods, all-or-none response, summation, and accommodation.
Myelin sheaths around axons allow saltatory conduction, where action potentials "jump" from one node of Ranvier to the next. This increases conduction velocity and is more energy efficient than action potentials propagating along the entire length of the axon. At synapses, the gap between neurons is bridged by neurotransmitters releasing from the presynaptic axon and signaling to the postsynaptic dendrite of the next neuron.
The document discusses the structure and function of chemical synapses. It begins by defining a synapse as the junction between two nerve cells. It then describes the key anatomical components of a chemical synapse, including the presynaptic knob, synaptic cleft, and postsynaptic membrane. It explains the process of neurotransmission, including the release of neurotransmitters into the synaptic cleft, their binding to receptors on the postsynaptic membrane, and the resulting postsynaptic potentials. The document also discusses inhibition at synapses, the properties of synaptic transmission, and examples of neurotransmitters.
This document discusses the generation and propagation of action potentials in neurons. It notes that neurons respond to stimuli by producing either local, non-propagated potentials or propagated action potentials. Action potentials are generated when voltage-gated sodium channels open in response to depolarization, allowing sodium ions to rush in and briefly reverse the membrane potential. This wave of depolarization then propagates down the axon by electrotonic conduction. The document outlines the changes in membrane permeability and potential during an action potential and describes how action potentials conduct in either direction along the axon.
This document provides an overview of synapses, including their definition, structure, function, types of transmission (electrical vs. chemical), neurotransmitters, and various properties like synaptic delay, fatigue, summation, and more. It discusses excitatory and inhibitory neurotransmitters and how convergence and divergence allow signals to be dispersed or combined. Clinical implications are that problems with synaptic transmission can cause diseases like Parkinson's and Alzheimer's.
Nervous system forms an interconnecting fibers of communication network.
In the ‘hard-wiring’ of the nerves, the signals travel in the form of a flow of electrical current called nerve impulses.
The stimulus-response reactions afford internal constancy in the face of environmental changes.
The resting membrane potential (RMP) refers to the stable voltage difference between the inside and outside of a cell membrane when the cell is not actively transmitting signals. The RMP results from selective permeability of ions like potassium and sodium across the membrane. At rest, the neuron's RMP is approximately -70mV due to higher intracellular potassium concentration creating a diffusion potential of -94mV, and lower intracellular sodium contributing +61mV. Additional contribution from the sodium-potassium pump, which actively transports ions against their gradients, results in the overall RMP of -90mV in neurons.
this ppt shares what synapses are and how information of one neuron is transmitted to other through the synapses. it also includes the properties and plasticity of synaptic transmission
Nerve fibers can be classified based on their structure and distribution. There are two main types - myelinated and unmyelinated fibers. Nerve fibers also include somatic and autonomic fibers. Somatic fibers innervate skeletal muscles and the neurotransmitter is acetylcholine, leading to muscle excitation or central inhibition. Autonomic fibers innervate smooth, cardiac muscles and glands to maintain homeostasis, causing excitation or inhibition. Important properties of nerve fibers include excitability, conductivity, unfatigability, refractory periods, all-or-none response, summation, and accommodation.
The document discusses action potentials and their propagation in excitable tissues. It begins by stating the objectives of understanding the mechanisms of action potential production and propagation. It then lists the main contents that will be covered, including the definition of action potential, its typical stages in large myelinated nerve fibers, the ion channels involved, propagation, and different types of action potentials. The document provides detailed explanations and diagrams of these topics. It emphasizes that action potentials are rapid changes in membrane potential that transmit signals through tissues via the coordinated opening and closing of sodium and potassium ion channels.
The oxyhemoglobin dissociation curve shows the relationship between oxygen concentration and hemoglobin saturation in the blood. It demonstrates how hemoglobin binds to oxygen in the lungs when partial pressure of oxygen is high, and releases oxygen into tissues where partial pressure is low. Several factors can shift the curve left or right, changing hemoglobin's affinity for oxygen and impacting how much oxygen is unloaded to tissues. These include pH, carbon dioxide levels, 2,3-DPG, temperature, and certain conditions like methemoglobinemia.
1. Neurons communicate via graded potentials over short distances and action potentials over long distances. Action potentials are generated when voltage-gated sodium channels open, causing rapid depolarization, followed by voltage-gated potassium channels opening to cause repolarization.
2. At chemical synapses, neurotransmitters are released from presynaptic terminals and bind to receptors on the postsynaptic cell, eliciting an excitatory or inhibitory response.
3. Faster conducting myelinated fibers like A fibers transmit touch and position sense while smaller unmyelinated C fibers transmit pain and temperature sensations. Fiber diameter, myelination and temperature influence conduction velocity.
- Excitable tissues like neurons and muscle cells have more negative resting membrane potentials (-70 to -90 mV) compared to non-excitable tissues like red blood cells (-40 mV) due to ion distributions and the sodium-potassium pump.
- When excitable cells are stimulated above a threshold, voltage-gated sodium channels open, causing rapid sodium influx and depolarization. Then, voltage-gated potassium channels open, causing repolarization.
- This generates an action potential that propagates along the cell membrane via local current flows, allowing nerve and muscle impulses to be transmitted. The sodium-potassium pump then restores ion gradients for the next action potential.
1) The resting membrane potential of a mammalian nerve cell is -90mV, maintained by the sodium-potassium pump that pumps 3Na+ ions out of the cell for every 2K+ ions into the cell.
2) An action potential occurs when the membrane potential rapidly changes from negative to positive and back again. It is triggered when voltage-gated sodium channels open and allow sodium ions to rush into the cell, reversing the potential.
3) Voltage-gated potassium channels then open, allowing potassium ions to efflux and repolarize the membrane back to its resting potential. The sodium-potassium pump then restores the ion gradients across the membrane.
Nerve fibers can be classified in six different ways: by structure, distribution, origin, function, neurotransmitter secretion, and diameter/impulse conduction. By structure, they are myelinated or non-myelinated. By distribution, they are somatic or autonomic. By origin, they are cranial or spinal. By function, they are sensory or motor. By neurotransmitter, they are adrenergic or cholinergic. By diameter/impulse conduction, Erlanger and Gasser classified them as type A, B, or C fibers with different speeds and functions.
The resting membrane potential of neurons and muscle cells is maintained around -70 mV due to selective permeability of ions across the cell membrane. The sodium-potassium pump actively transports 3 Na+ ions out and 2 K+ ions into the cell, contributing to the negative interior potential. When the membrane potential reaches the threshold, voltage-gated sodium channels open rapidly, causing a sharp depolarization as sodium ions rush in. Subsequently, voltage-gated potassium channels open more slowly, repolarizing the membrane as potassium ions efflux from the cell. This generates an action potential that propagates by local current flow between adjacent areas of the membrane. The sodium-potassium pump then restores ion gradients in preparation for the next action potential
This document provides information about synapses and synaptic transmission in the central nervous system (CNS). It defines a synapse as the junction between two neurons and discusses the key anatomical structures involved, including the presynaptic terminal, synaptic cleft, and postsynaptic membrane. It describes how an action potential in the presynaptic neuron leads to calcium ion influx and neurotransmitter release into the synaptic cleft. The neurotransmitters then bind to receptors on the postsynaptic membrane, which can result in excitation via EPSPs or inhibition via IPSPs depending on the specific neurotransmitter and receptor type involved. Higher-level functions such as learning and memory emerge from the complex integration of signals at numerous synapses throughout the CNS neural circuits.
Generation and conduction of action potentialsCsilla Egri
This document provides an overview of action potentials and nerve conduction. It discusses synaptic transmission through both electrical and chemical synapses. It then covers the major classes of neurotransmitters and neurotransmitter receptors. The document reviews graded potentials, spatial and temporal summation, and electrotonic conduction. It describes the ionic basis and phases of the action potential as well as how action potentials propagate along axons. Finally, it discusses nerve conduction disorders like demyelination and multiple sclerosis.
Lecture 5 (membrane potential and action potential)Ayub Abdi
This document discusses membrane potentials and action potentials in excitable cells like neurons and muscles. It covers:
1. The resting membrane potential of -70mV that is maintained by selective permeability of potassium ions and active transport by the sodium-potassium pump.
2. How an action potential is generated when the membrane reaches its threshold voltage due to an influx of sodium ions, causing rapid depolarization. It then repolarizes as potassium ions efflux.
3. The propagation of action potentials along neurons or muscle fibers to transmit electrical signals and cause effects like muscle contraction or neurotransmitter release.
This document discusses the two main mechanisms that control respiration: the neural and chemical mechanisms. It describes in detail the various centers in the brainstem that control respiration, including the dorsal respiratory group, ventral respiratory group, pneumotaxic center, and apneustic center. It also discusses the voluntary, automatic, and reflex control of respiration, including various reflexes like the Hering-Breuer reflex. Other factors that can affect respiration like sleep and receptors outside the respiratory system are also summarized.
The document summarizes the mechanism of skeletal muscle contraction. It describes how an action potential leads to a rise in intracellular calcium levels through excitation-contraction coupling. This triggers the sliding filament theory where actin and myosin filaments slide past each other through cross-bridge cycling powered by ATP hydrolysis. Calcium binds to troponin C, allowing the power stroke to occur as myosin heads pull the actin filaments towards the center of the sarcomere. Relaxation occurs as calcium is re-sequestered in the sarcoplasmic reticulum, breaking the cross-bridges.
EPSP is an excitatory postsynaptic potential that occurs when a neurotransmitter like glutamate binds to receptors on the postsynaptic neuron, making its membrane permeable to sodium ions and depolarizing the neuron. IPSP is an inhibitory postsynaptic potential that occurs when GABA binds to receptors, making the membrane permeable to chloride ions and hyperpolarizing the neuron. EPSPs can summate and cause the neuron to generate an action potential, while IPSPs make action potential generation less likely. Together, the balance of EPSPs and IPSPs control whether a neuron will fire an action potential.
There are four main types of gated ion channels that open or close in response to different stimuli: voltage-gated, chemically-gated, mechanically-gated, and thermally-gated channels. Graded potentials are local changes in membrane potential that vary in strength and duration depending on the stimulus. They can be excitatory or inhibitory and occur through temporal or spatial summation of incremental stimuli at the dendrite or soma. Graded potentials spread passively within the cell and may cause a secondary action potential if they reach the axon hillock threshold.
The membrane potential arises from separation of charges across the plasma membrane due to unequal distribution of ions such as sodium, potassium, and chloride between the intracellular and extracellular fluids. Nerve and muscle cells have the greatest membrane potential due to their ability to generate rapid changes in potential when stimulated. The resting membrane potential results from small passive leak of potassium out of the cell, generating a potential of around -70 mV. An action potential is initiated when the membrane potential surpasses the threshold, causing voltage-gated sodium channels to open and allow sodium to rush in, rapidly depolarizing the membrane before voltage-gated potassium channels open to repolarize it.
1) The motor cortex and corticospinal tract provide conscious control of voluntary skeletal muscle movements. The corticospinal tract contains fibers that cross to the opposite side of the body and fibers that remain on the same side.
2) Sensory information travels through ascending tracts in the spinal cord including the posterior, lateral, and spinocerebellar tracts to the brain.
3) The medial and lateral motor pathways issue subconscious motor commands through tracts like the rubrospinal and reticulospinal tracts to control gross movements and posture.
Bohr’s effect- The Bohr effect is a physiological phenomenon first described by Danish physiological Christian Bohr, stating that the “oxygen binding affinity of hemoglobin is inversely related to the concentration of carbon dioxide and hydrogen ion.
#An increase in blood CO2 concentration which leads to decrease in blood pH will results in hemoglobin proteins releasing their oxygen load.
#One of the factor that Bohr discovered was pH. He found that if the pH is lower than the normal, then hemoglobin does not bind oxygen.
#And this effect of CO2 on oxygen dissociation curve is known as Bohr effect.
Haldane effect- The Haldane effect is first discovered by John Scott Haldane.
#The Haldane effect describe the phenomenon by which binding of oxygen to hemoglobin promotes the release of carbon dioxide.
#Haldane effect is the mirror image of Bohr effect.
#The decrease in carbon dioxide leads to increase in the pH, which result in hemoglobin picking up more oxygen.
#This is a helpful biochemical feature which facilitates exchange of carbon dioxide for oxygen in the pulmonary and peripheral circulations.
General Physiology - The nervous system, basic functions of synapsesHamzeh AlBattikhi
The document summarizes the organization and functions of the nervous system. It discusses the following key points:
1. The central nervous system contains over 100 billion neurons with dendrites that receive signals and axons that transmit signals in a forward direction via synapses.
2. There are three major levels of the central nervous system - the spinal cord level controls basic reflexes, the lower brain/subcortical level controls subconscious functions, and the higher brain/cortical level is responsible for thought processes and stores memories.
3. Synaptic transmission occurs either chemically via neurotransmitters like acetylcholine and glutamate, or electrically through direct connections. Neurotransmitters are stored in vesicles and released
The document summarizes membrane potentials and action potentials in nerve cells. It discusses:
1) The concentration gradients that give rise to resting membrane potentials via the Nernst equation and Goldman equation. Key ions like sodium, potassium and chloride contribute to a resting potential of around -90mV.
2) How action potentials are initiated when the membrane reaches a threshold potential, causing voltage-gated sodium channels to open and depolarize the membrane. Potassium channels then open to repolarize the membrane.
3) The roles of other ions like calcium and various ion pumps and channels in maintaining resting potentials and propagating action potentials down nerve fibers via saltatory conduction. Action potentials rely on precise ion concentration gradients maintained
The membrane potential is the voltage difference between the interior and exterior of a cell membrane. It arises from differences in ion concentrations across the membrane. Key ions that contribute to the membrane potential include sodium (Na+), potassium (K+), calcium (Ca2+), and chloride (Cl-). The resting membrane potential of most cells is approximately -70mV, due primarily to higher intracellular potassium concentration compared to extracellular. Movement of potassium and sodium ions through membrane channels works to maintain this voltage difference at equilibrium.
1st year medical school physiology essay:
Describe the effects between the action potential arriving at the axon terminal and skeletal muscle contraction.
The document discusses action potentials and their propagation in excitable tissues. It begins by stating the objectives of understanding the mechanisms of action potential production and propagation. It then lists the main contents that will be covered, including the definition of action potential, its typical stages in large myelinated nerve fibers, the ion channels involved, propagation, and different types of action potentials. The document provides detailed explanations and diagrams of these topics. It emphasizes that action potentials are rapid changes in membrane potential that transmit signals through tissues via the coordinated opening and closing of sodium and potassium ion channels.
The oxyhemoglobin dissociation curve shows the relationship between oxygen concentration and hemoglobin saturation in the blood. It demonstrates how hemoglobin binds to oxygen in the lungs when partial pressure of oxygen is high, and releases oxygen into tissues where partial pressure is low. Several factors can shift the curve left or right, changing hemoglobin's affinity for oxygen and impacting how much oxygen is unloaded to tissues. These include pH, carbon dioxide levels, 2,3-DPG, temperature, and certain conditions like methemoglobinemia.
1. Neurons communicate via graded potentials over short distances and action potentials over long distances. Action potentials are generated when voltage-gated sodium channels open, causing rapid depolarization, followed by voltage-gated potassium channels opening to cause repolarization.
2. At chemical synapses, neurotransmitters are released from presynaptic terminals and bind to receptors on the postsynaptic cell, eliciting an excitatory or inhibitory response.
3. Faster conducting myelinated fibers like A fibers transmit touch and position sense while smaller unmyelinated C fibers transmit pain and temperature sensations. Fiber diameter, myelination and temperature influence conduction velocity.
- Excitable tissues like neurons and muscle cells have more negative resting membrane potentials (-70 to -90 mV) compared to non-excitable tissues like red blood cells (-40 mV) due to ion distributions and the sodium-potassium pump.
- When excitable cells are stimulated above a threshold, voltage-gated sodium channels open, causing rapid sodium influx and depolarization. Then, voltage-gated potassium channels open, causing repolarization.
- This generates an action potential that propagates along the cell membrane via local current flows, allowing nerve and muscle impulses to be transmitted. The sodium-potassium pump then restores ion gradients for the next action potential.
1) The resting membrane potential of a mammalian nerve cell is -90mV, maintained by the sodium-potassium pump that pumps 3Na+ ions out of the cell for every 2K+ ions into the cell.
2) An action potential occurs when the membrane potential rapidly changes from negative to positive and back again. It is triggered when voltage-gated sodium channels open and allow sodium ions to rush into the cell, reversing the potential.
3) Voltage-gated potassium channels then open, allowing potassium ions to efflux and repolarize the membrane back to its resting potential. The sodium-potassium pump then restores the ion gradients across the membrane.
Nerve fibers can be classified in six different ways: by structure, distribution, origin, function, neurotransmitter secretion, and diameter/impulse conduction. By structure, they are myelinated or non-myelinated. By distribution, they are somatic or autonomic. By origin, they are cranial or spinal. By function, they are sensory or motor. By neurotransmitter, they are adrenergic or cholinergic. By diameter/impulse conduction, Erlanger and Gasser classified them as type A, B, or C fibers with different speeds and functions.
The resting membrane potential of neurons and muscle cells is maintained around -70 mV due to selective permeability of ions across the cell membrane. The sodium-potassium pump actively transports 3 Na+ ions out and 2 K+ ions into the cell, contributing to the negative interior potential. When the membrane potential reaches the threshold, voltage-gated sodium channels open rapidly, causing a sharp depolarization as sodium ions rush in. Subsequently, voltage-gated potassium channels open more slowly, repolarizing the membrane as potassium ions efflux from the cell. This generates an action potential that propagates by local current flow between adjacent areas of the membrane. The sodium-potassium pump then restores ion gradients in preparation for the next action potential
This document provides information about synapses and synaptic transmission in the central nervous system (CNS). It defines a synapse as the junction between two neurons and discusses the key anatomical structures involved, including the presynaptic terminal, synaptic cleft, and postsynaptic membrane. It describes how an action potential in the presynaptic neuron leads to calcium ion influx and neurotransmitter release into the synaptic cleft. The neurotransmitters then bind to receptors on the postsynaptic membrane, which can result in excitation via EPSPs or inhibition via IPSPs depending on the specific neurotransmitter and receptor type involved. Higher-level functions such as learning and memory emerge from the complex integration of signals at numerous synapses throughout the CNS neural circuits.
Generation and conduction of action potentialsCsilla Egri
This document provides an overview of action potentials and nerve conduction. It discusses synaptic transmission through both electrical and chemical synapses. It then covers the major classes of neurotransmitters and neurotransmitter receptors. The document reviews graded potentials, spatial and temporal summation, and electrotonic conduction. It describes the ionic basis and phases of the action potential as well as how action potentials propagate along axons. Finally, it discusses nerve conduction disorders like demyelination and multiple sclerosis.
Lecture 5 (membrane potential and action potential)Ayub Abdi
This document discusses membrane potentials and action potentials in excitable cells like neurons and muscles. It covers:
1. The resting membrane potential of -70mV that is maintained by selective permeability of potassium ions and active transport by the sodium-potassium pump.
2. How an action potential is generated when the membrane reaches its threshold voltage due to an influx of sodium ions, causing rapid depolarization. It then repolarizes as potassium ions efflux.
3. The propagation of action potentials along neurons or muscle fibers to transmit electrical signals and cause effects like muscle contraction or neurotransmitter release.
This document discusses the two main mechanisms that control respiration: the neural and chemical mechanisms. It describes in detail the various centers in the brainstem that control respiration, including the dorsal respiratory group, ventral respiratory group, pneumotaxic center, and apneustic center. It also discusses the voluntary, automatic, and reflex control of respiration, including various reflexes like the Hering-Breuer reflex. Other factors that can affect respiration like sleep and receptors outside the respiratory system are also summarized.
The document summarizes the mechanism of skeletal muscle contraction. It describes how an action potential leads to a rise in intracellular calcium levels through excitation-contraction coupling. This triggers the sliding filament theory where actin and myosin filaments slide past each other through cross-bridge cycling powered by ATP hydrolysis. Calcium binds to troponin C, allowing the power stroke to occur as myosin heads pull the actin filaments towards the center of the sarcomere. Relaxation occurs as calcium is re-sequestered in the sarcoplasmic reticulum, breaking the cross-bridges.
EPSP is an excitatory postsynaptic potential that occurs when a neurotransmitter like glutamate binds to receptors on the postsynaptic neuron, making its membrane permeable to sodium ions and depolarizing the neuron. IPSP is an inhibitory postsynaptic potential that occurs when GABA binds to receptors, making the membrane permeable to chloride ions and hyperpolarizing the neuron. EPSPs can summate and cause the neuron to generate an action potential, while IPSPs make action potential generation less likely. Together, the balance of EPSPs and IPSPs control whether a neuron will fire an action potential.
There are four main types of gated ion channels that open or close in response to different stimuli: voltage-gated, chemically-gated, mechanically-gated, and thermally-gated channels. Graded potentials are local changes in membrane potential that vary in strength and duration depending on the stimulus. They can be excitatory or inhibitory and occur through temporal or spatial summation of incremental stimuli at the dendrite or soma. Graded potentials spread passively within the cell and may cause a secondary action potential if they reach the axon hillock threshold.
The membrane potential arises from separation of charges across the plasma membrane due to unequal distribution of ions such as sodium, potassium, and chloride between the intracellular and extracellular fluids. Nerve and muscle cells have the greatest membrane potential due to their ability to generate rapid changes in potential when stimulated. The resting membrane potential results from small passive leak of potassium out of the cell, generating a potential of around -70 mV. An action potential is initiated when the membrane potential surpasses the threshold, causing voltage-gated sodium channels to open and allow sodium to rush in, rapidly depolarizing the membrane before voltage-gated potassium channels open to repolarize it.
1) The motor cortex and corticospinal tract provide conscious control of voluntary skeletal muscle movements. The corticospinal tract contains fibers that cross to the opposite side of the body and fibers that remain on the same side.
2) Sensory information travels through ascending tracts in the spinal cord including the posterior, lateral, and spinocerebellar tracts to the brain.
3) The medial and lateral motor pathways issue subconscious motor commands through tracts like the rubrospinal and reticulospinal tracts to control gross movements and posture.
Bohr’s effect- The Bohr effect is a physiological phenomenon first described by Danish physiological Christian Bohr, stating that the “oxygen binding affinity of hemoglobin is inversely related to the concentration of carbon dioxide and hydrogen ion.
#An increase in blood CO2 concentration which leads to decrease in blood pH will results in hemoglobin proteins releasing their oxygen load.
#One of the factor that Bohr discovered was pH. He found that if the pH is lower than the normal, then hemoglobin does not bind oxygen.
#And this effect of CO2 on oxygen dissociation curve is known as Bohr effect.
Haldane effect- The Haldane effect is first discovered by John Scott Haldane.
#The Haldane effect describe the phenomenon by which binding of oxygen to hemoglobin promotes the release of carbon dioxide.
#Haldane effect is the mirror image of Bohr effect.
#The decrease in carbon dioxide leads to increase in the pH, which result in hemoglobin picking up more oxygen.
#This is a helpful biochemical feature which facilitates exchange of carbon dioxide for oxygen in the pulmonary and peripheral circulations.
General Physiology - The nervous system, basic functions of synapsesHamzeh AlBattikhi
The document summarizes the organization and functions of the nervous system. It discusses the following key points:
1. The central nervous system contains over 100 billion neurons with dendrites that receive signals and axons that transmit signals in a forward direction via synapses.
2. There are three major levels of the central nervous system - the spinal cord level controls basic reflexes, the lower brain/subcortical level controls subconscious functions, and the higher brain/cortical level is responsible for thought processes and stores memories.
3. Synaptic transmission occurs either chemically via neurotransmitters like acetylcholine and glutamate, or electrically through direct connections. Neurotransmitters are stored in vesicles and released
The document summarizes membrane potentials and action potentials in nerve cells. It discusses:
1) The concentration gradients that give rise to resting membrane potentials via the Nernst equation and Goldman equation. Key ions like sodium, potassium and chloride contribute to a resting potential of around -90mV.
2) How action potentials are initiated when the membrane reaches a threshold potential, causing voltage-gated sodium channels to open and depolarize the membrane. Potassium channels then open to repolarize the membrane.
3) The roles of other ions like calcium and various ion pumps and channels in maintaining resting potentials and propagating action potentials down nerve fibers via saltatory conduction. Action potentials rely on precise ion concentration gradients maintained
The membrane potential is the voltage difference between the interior and exterior of a cell membrane. It arises from differences in ion concentrations across the membrane. Key ions that contribute to the membrane potential include sodium (Na+), potassium (K+), calcium (Ca2+), and chloride (Cl-). The resting membrane potential of most cells is approximately -70mV, due primarily to higher intracellular potassium concentration compared to extracellular. Movement of potassium and sodium ions through membrane channels works to maintain this voltage difference at equilibrium.
1st year medical school physiology essay:
Describe the effects between the action potential arriving at the axon terminal and skeletal muscle contraction.
The document discusses the generation and propagation of action potentials in neurons. It begins by explaining the resting membrane potential, which arises from ion concentration gradients maintained by the sodium-potassium pump and potassium leakage channels. It then describes how an action potential is triggered when the membrane potential reaches a threshold, causing voltage-gated sodium channels to open and sodium ions to rush in, rapidly depolarizing the membrane. This wave of depolarization then propagates along the neuron as adjacent areas are triggered to reach threshold. The action potential involves sequential phases of depolarization, repolarization, and hyperpolarization.
During a nerve impulse, sodium ions enter the axon, reversing the voltage and depolarizing the inside. This generates an action potential that travels down the axon. Potassium ions then shift the voltage negative again, returning the axon to its resting polarized state, ready to transmit another impulse if stimulated.
The Resting Potential And The Action Potentialneurosciust
An action potential occurs when a neuron is stimulated enough to reach its threshold of excitation. This causes sodium channels to open, allowing sodium to rush into the neuron and depolarize it. The neuron then repolarizes as potassium leaves and the sodium-potassium pump restores the ion gradients. After an action potential, the neuron enters an absolute refractory period where it cannot fire again, followed by a relative refractory period where a stronger stimulus is needed to trigger another action potential. This process allows neurons to rapidly transmit signals down axons to synapse with other neurons.
Neurons transmit electrical signals along their axons via action potentials. At synapses, neurotransmitters carry signals between neurons. When an action potential reaches a presynaptic neuron, calcium ions enter and cause neurotransmitter vesicles to fuse and release their contents. Neurotransmitters diffuse across the synapse and bind to receptors, sometimes triggering an action potential in the postsynaptic neuron. Myelination allows saltatory conduction to increase signal propagation speed along axons.
Nerve impulse conduction involves the generation and propagation of action potentials along neurons. At rest, neurons maintain a negative resting potential due to an unequal distribution of ions across the cell membrane. When stimulated, the opening of voltage-gated sodium channels causes rapid depolarization and the generation of an action potential. This potential then propagates along the axon as adjacent regions are depolarized, triggering their own action potentials. At synapses, the action potential is converted to a chemical signal via neurotransmitter release, which can then trigger a new action potential in the post-synaptic cell. Myelination and large axon diameters increase conduction velocity.
General principles of surgery - medical finals revision notesChristiane Riedinger
1) This document provides an overview of general principles for surgical management, including pre-operative assessment and optimization of medical conditions, guidelines for fluid treatment and antibiotic prophylaxis, and considerations for specific diseases.
2) Key aspects of pre-op management discussed include reviewing medications, performing tests like ECG and imaging, addressing comorbidities, and obtaining informed consent.
3) Fluid treatment principles focus on maintaining fluid and electrolyte balance, with crystalloids being preferred to colloids due to safety concerns. Goals include compensation for losses in different fluid compartments.
1. An action potential, or nerve impulse, occurs when a neuron reaches its threshold level and is stimulated to send a message along its axon.
2. The action potential involves two steps - depolarization, where sodium ions rush into the neuron, reversing the charge; and repolarization, where potassium ions rush out, restoring the charge.
3. After repolarization, the sodium-potassium pump restores the ion concentrations to prepare the neuron to fire again if stimulated. Myelin insulation allows the impulse to jump from node to node, speeding up conduction.
A summary for learning the muscles of the upper limb including their attachments, innervation, etc., without having to have too many books open. Resources: "Gray’s Anatomy", "Taschenatlas der Anatomie" and Wikipedia. Awaiting further proof-reading!
The document discusses the neurobiology behind the remarkable skill of high school debaters who can speak at over 250 words per minute, which is nearly double the normal speech rate. It explores the complex neural regions and processes involved in speech production, including Broca's area, Wernicke's area, motor neurons, and right hemisphere involvement. It suggests debaters have highly familiar materials allowing pre-packaged motor sequences, faster processing speeds to rapidly transition between thinking and speaking, and possibly thicker myelin sheaths to facilitate faster neural processing. Their speech also exhibits little prosody or emotion, likely due to minimal right hemisphere involvement or control over its typical contributions to speech.
This document summarizes key concepts about graded and action potentials from chapter 10, section 4 of an anatomy textbook. It describes how graded potentials are localized changes in membrane potential that summate to reach threshold and trigger an action potential. An action potential has 3 phases: depolarization due to sodium influx, repolarization due to potassium efflux, and hyperpolarization. It propagates along the axon via adjacent regions reaching threshold. The all-or-none property and refractory period are also summarized. Diagrams illustrate these concepts.
This document summarizes key aspects of impulse conduction and neurotransmitters discussed in Chapter 10. It describes how myelinated axons conduct impulses faster than unmyelinated axons via saltatory conduction between nodes of Ranvier. It also explains how neurotransmitters are released at synapses and can either excite or inhibit postsynaptic neurons through EPSPs and IPSPs. Summation of these synaptic potentials determines whether an action potential is triggered in the postsynaptic cell. Examples of different neurotransmitters like acetylcholine, monoamines, amino acids, and gases are provided, along with how neuronal pools process nerve impulses through convergence and divergence.
We evaulate the impact of measurement error on three components of a forest planning model: initial inventory, first period harvest and silvicultural activities chosen. Calculated initial inventory was off by as much as 15%, and significantly different objective function values and activity schedule also resulted.
This document contains the questions and instructions for a baby shower quiz game. The quiz is divided into 5 parts that send participants to different areas of a house or garden. Participants are asked questions about baby names, pregnancy, famous moms, and to identify babies in pictures. The quiz aims to test the participants' knowledge of babies, pregnancy, and famous mothers.
Initiation or generation of a nerve impulseRajesh Sn
The document summarizes how a nerve impulse is initiated and transmitted. At rest, sodium and potassium gates are closed, maintaining a -70mV potential. When stimulated, sodium gates open, allowing sodium to enter and depolarize the membrane to +30mV. Then potassium gates open, repolarizing the membrane back to -70mV. This rapid depolarization and repolarization generates an action potential that is transmitted along the axon to the synaptic knob. At the synapse, neurotransmitters are released into the cleft and can trigger a new action potential in the receiving neuron.
The document discusses the structure and function of the human nervous system. It describes how the nervous system is divided into the central nervous system (CNS) and peripheral nervous system (PNS). The CNS contains the brain and spinal cord, while the PNS connects them to sensory receptors and effector organs. The nervous system receives sensory input, integrates the information in the CNS, and sends motor responses through the PNS to coordinate body functions and maintain homeostasis.
An action potential is generated when an impulse reaches a point on an axon. This causes local currents that excite the next part of the axon, allowing the action potential to progress along the length of the axon. The passage of an action potential is followed by a refractory period where the axon membrane is unable to generate another action potential to allow impulses to travel in one direction. Myelination of axons speeds up impulse transmission by allowing action potentials to "jump" between nodes of Ranvier.
El documento habla sobre la generación y conducción del potencial de acción en neuronas. Explica que la resistencia y capacitancia son propiedades independientes de un conductor y cómo la conducción activa ocurre en el axón generando un evento imparable. También discute cómo la actividad neuronal depende del ajuste del potencial de membrana, las regiones generadoras del impulso, y cómo los estímulos en diferentes sentidos afectan la continuidad del estimulo a lo largo de la neurona.
The document discusses error propagation in physics measurements and calculations. It provides formulas for calculating the uncertainty (error) when adding, subtracting, multiplying and dividing measurements. The key points are:
1) When adding or subtracting measurements, the total uncertainty is the square root of the sum of the individual measurement uncertainties squared.
2) When multiplying or dividing measurements, the total uncertainty is calculated by adding the individual relative uncertainties squared.
3) For measurements raised to a power, the relative uncertainty is equal to the relative uncertainty of the measurement itself multiplied by the power.
Nerve cells transmit electrical signals through action potentials. Action potentials are brief changes in the electrical potential across the cell membrane that are triggered when the membrane potential reaches a threshold. They are generated by the rapid influx of sodium ions through voltage-gated sodium channels, which causes further opening of these channels in a positive feedback loop. After peaking, the membrane repolarizes as sodium channels inactivate and potassium channels open, restoring the ion gradients. Action potentials propagate along axons without loss of strength through the active opening of sodium channels just beyond the leading edge of depolarization.
Neuroglia, also known as glial cells, provide support and insulation to neurons in the central and peripheral nervous systems. There are two main types of neuroglia: microglia and macroglia. Microglia are small phagocytic cells found throughout the central nervous system, while macroglia include astrocytes, oligodendrocytes, Schwann cells, and other larger glial cells. Astrocytes help form the blood-brain barrier and regulate neurotransmitters. Oligodendrocytes and Schwann cells are responsible for myelination in the central and peripheral nervous systems respectively. Nerve fibers have properties like excitability, conductivity, following the all-or-none principle, and
BioT2C3-Action potential-transmission of impulse 2015-student.pptgov
The document discusses resting potential and action potential in neurons. It defines resting potential as the membrane potential of a neuron when not conducting an impulse, which is around -70 mV for a resting neuron. It defines action potential as the state of the cell membrane while conducting an impulse, which is triggered when voltage-gated sodium channels open and sodium rushes into the cell, reversing the charge difference and allowing propagation of the impulse along the axon.
NERVE AND MUSCLE VETERINARY PHYSIOLOGY .pdfTatendaMageja
The document discusses neurons, their anatomy, membrane potentials, and synaptic transmission. It provides details on:
- The structure and function of neurons as electrically excitable cells that transmit electrical and chemical signals.
- The resting membrane potential of neurons, which results from ion concentration gradients maintained by ion pumps and channels. An action potential occurs when the membrane potential rapidly changes due to opening of voltage-gated sodium channels.
- Synaptic transmission, where neurons communicate via electrical or chemical synapses. Calcium influx through voltage-gated calcium channels triggers the release of neurotransmitters from synaptic vesicles into the synaptic cleft.
The document discusses membrane potential and action potentials. It begins by defining action potentials as signals that trigger communication between cells through electrical and chemical signaling. It then discusses:
- Excitable cells like neurons, muscle and endocrine cells that are able to generate and conduct action potentials.
- The resting membrane potential of -70mV that exists due to ion concentration gradients established by the sodium-potassium pump and selective permeability of the membrane.
- How action potentials are initiated when the membrane potential rapidly depolarizes past a threshold due to opening of voltage-gated sodium channels, then repolarizes due to opening of voltage-gated potassium channels.
1. The document discusses facilitated diffusion, which is the transport of substances across a membrane with the aid of carrier proteins. It involves substances moving uphill against a concentration gradient, with the carrier protein having a fixed affinity for the substance and ATP being used to flip the orientation or change the affinity of the binding site.
2. It then covers the resting membrane potential, how cells create charge separation across the membrane by establishing ion concentration gradients and allowing diffusion through leak channels, and how this results in a membrane potential. Key ions involved are sodium, potassium, and macromolecular anions.
3. It defines graded potentials as local changes in membrane potential caused by transient opening of non-voltage gated ion channels that
1. Nerve and muscle cells are excitable tissues that can generate electrochemical impulses. In nerves, these impulses propagate signals along the axon when stimulated, whereas in muscles they cause contraction.
2. The resting membrane potential of these cells is maintained by ion concentration gradients and selective permeability of the membrane to ions like sodium, potassium, and chloride. At rest, the intracellular fluid is negatively charged relative to the extracellular fluid.
3. An action potential occurs when the membrane potential rapidly changes from the resting potential to a positive overshoot then back again. This is driven by changes in sodium and potassium conductance across the membrane.
1) Action potentials are electrical signals that propagate along excitable cell membranes and are initiated by stimuli. They involve the movement of ions through voltage-gated ion channels.
2) In neurons, an action potential is a brief reversal of the membrane potential followed by repolarization. This allows communication over long distances.
3) Cardiac action potentials have a depolarizing phase, plateau phase, and repolarizing phase due to calcium ion involvement. This allows for sustained contraction of heart muscle.
This document summarizes how electrical and chemical information is conducted along nerve cells through three main mechanisms:
1) Electrotonic conduction allows information to spread over short distances through passive membrane properties but signal strength decays rapidly with distance.
2) Regenerative conduction of action potentials allows signals to travel long distances without decay through the continuous generation of new action potentials.
3) Intracellular transport of molecules along microtubules within nerve processes helps distribute resources needed for signal transmission.
The document discusses how electrical signals are conducted along nerve cells through two main mechanisms: electrotonic conduction and regenerative conduction. Electrotonic conduction relies on passive spread of current and is limited to short distances. Regenerative conduction uses voltage-gated ion channels to actively propagate action potentials along the entire length of a nerve fiber without degradation. Myelinated fibers use a specialized form of regenerative conduction called saltatory conduction, which allows rapid jumping of the action potential between nodes of Ranvier.
1. The document discusses the basics of nerve structure, electrical current, capacitance, resistance, and action potentials.
2. It defines key concepts like resting potential, depolarization, repolarization, and hyperpolarization that characterize the phases of an action potential.
3. The action potential results from changes in sodium and potassium permeability that cause the membrane potential to rapidly shift from its resting potential of -70mV to a peak of +30mV before returning to the resting potential.
Ion channels are membrane proteins that allow ions to pass through their pore, regulating ion flow and electrical signals. There are two main types of gated ion channels: ligand-gated channels, which open when neurotransmitters bind, and voltage-gated channels, which open in response to changes in membrane potential. Ligand-gated channels allow sodium influx upon acetylcholine binding, depolarizing the membrane and triggering action potentials. Voltage-gated channels maintain the resting potential and enable action potential propagation along axons by selectively transporting sodium, potassium, calcium, and chloride ions in response to changes in voltage.
The document discusses membrane potential and action potentials in neurons. It provides details on:
- The resting membrane potential is established by ion gradients maintained by the sodium-potassium pump. There is a net negative charge inside and positive outside the membrane.
- An action potential is initiated when the membrane reaches its threshold potential due to sodium influx. It involves stages of depolarization, repolarization and refractory periods.
- The all-or-none principle states that an action potential will only be generated if the threshold is reached. Speed and propagation depends on myelination.
- Different cell types like cardiac and smooth muscles exhibit variations in their action potential waveforms.
1) All cells possess electrical excitability, the ability to generate an action potential in response to a stimulus.
2) An action potential is an electrical signal that propagates along the neuronal membrane due to the movement of sodium and potassium ions through ion channels.
3) The resting membrane potential is maintained by the uneven distribution of ions across the membrane and the sodium-potassium pump, which works to keep the intracellular concentration of sodium ions low and potassium ions high.
6. Write a description of a neuron at rest. What happens to a neuron.pdfinfo998421
6. Write a description of a neuron at rest. What happens to a neuron that results in the action
potential? Include the following terms: semi-permeable cell membrane; electrostatic forces;
concentration gradient; ion channel; Na+; K+; sodium-potassium pump; EPSP; IPSP; threshold
[3 points; 1 for including all the terms, 2 for describing accurately]
Solution
neuron:they are the masses of nerve cells that transmits information.
neuron at rest:when a neuron is not responding to a signal it is at rest,when a neuron is in resting
state the axonal membrane is comparitively more permeable to potassium K+ and almost
imppermeable to sodium ions Na+.in the same way the membrane is impermeable to negatively
charged proteins present in the axoplasm.the axoplasm inside the axon contains high
concentrations of K+ and a high concentration of Na+ forming a concentration gradient. the
electrostatic forces help them to ability to conduct...the ionic gradients across the resting
membrane are maintained by active transport of ions by the sodium potassium pump.it transports
3Na+ outwards and2K+ in to the cell the outer surface of the axonal membrane possesses a
positive charge it inner surface contain a negative charge and gets polarised.the electrical
potential across the resting plasma membrane is called resting potential or polarization
neuron that results in action potential :when a neuron is stimulus it is applied on the site of a
polarized membrane.the membrane at that site becomes freely permeable to Na+.this leads to a
rapid influx of Na+ followed by the reversal of the polarity at that site, outer surface of
membrane becomes negatively charged and the inner side becomes positively charged . the
polarity of the membrane at the site -a is called action potential.or depolarisation.or also termed
as nerve impulse.the EPSP deplorise the membrane and move closer to the thersold for action
potential.IPSP hypolarise the membrane and moves farther away to the potential.....
This document provides an overview of neuron structure and nerve impulse propagation. It discusses the key components of a neuron including the cell body, dendrites and axon. It describes ion channels and their role in establishing the resting membrane potential. The document explains how an action potential is generated through a positive feedback loop initiated at the threshold. It discusses the absolute and relative refractory periods and how conduction velocity depends on the diameter and myelination of the axon. In summary, the document outlines the basics of neuron anatomy and function, focusing on membrane potentials, ion channels, action potential generation and propagation.
This presentation focuses on detail of the contraction of the contractile fibers in the muscles. short introduction to the ion channels, different potentials and phases working on the contraction of the muscles.
Reference: Anatomy, Physiology & Pathophysiology by Gerard J. Tortora
The action potential conveys information over distance in the nervous system through a rapid reversal of the membrane potential at rest. It is generated when the membrane potential is depolarized beyond a threshold, causing an "all-or-nothing" event. The rising phase of the action potential is caused by sodium influx through voltage-gated sodium channels, while the falling phase occurs via potassium efflux through voltage-gated potassium channels. The action potential is able to propagate down the axon due to its unique ion channel properties and myelination of axons, which facilitates faster saltatory conduction.
The document discusses membrane potential and action potentials. It states that (a) and (e) are correct - if Na/K ATPase pumps were disabled, the membrane potential would fall to zero, and at resting potential the outward driving force on K exactly counterbalances the inward driving force.
Similar to The propagation of action potentials along the axon. (20)
Christiane Riedinger's document defines and describes different types of hernias, including inguinal, femoral, umbilical, and incisional hernias. It discusses the anatomy of the abdominal wall, inguinal canal, and femoral canal. The document also outlines predisposing factors for abdominal hernias and important surface anatomy landmarks. Finally, it briefly describes common surgical hernia repair procedures like herniotomy, herniorrhaphy, and laparoscopic hernia repair.
This document discusses the examination and evaluation of lumps in the neck and on the skin. It provides guidance on how to describe lumps and outlines the broad categories of neck lumps including lymph nodes, salivary glands, thyroid, vascular structures and more. It lists relevant investigations and treatments for different types of lumps. Common benign and malignant skin lesions are discussed. Surgical procedures for removing various lumps are also summarized.
This document provides an overview of breast surgery, including:
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This document provides an overview of palliative care notes covering several topics:
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2) Disease trajectories vary between cancer, chronic illnesses, and dementia. Prognostication requires open communication of uncertainty alongside hopes for the best but preparation for the worst.
3) End of life care focuses on comfort, symptom management using drugs in a "just in case" box, and allowing natural death according to preferences whether at home or elsewhere.
This document provides a summary of key topics in neurology for revision purposes. It covers diagnostic reasoning in neurology including the importance of considering tempo of onset and localizing lesions. It also summarizes some key neuroanatomy including ascending and descending pathways. Examination findings like the MRC scale and features of increased tone are defined. Pathological gaits, cerebellar signs, brainstem symptoms, and spinal cord symptoms are also outlined.
This document provides information on describing heart murmurs, heart sounds, and the jugular vein pressure (JVP) waveform. It discusses the timing, shape, location, and other characteristics of murmurs. It describes the first, second, third, and fourth heart sounds and what they indicate. It also explains how to assess the JVP waveform and what the different waves mean in terms of cardiac function. Causes of elevated JVP are outlined. Key information on cardiac auscultation and assessment of the JVP is summarized.
This document provides information on various heart murmurs, including their causes, associated symptoms, physical exam findings like location of murmurs and thrills, consequences, and recommended tests and treatments. It covers murmurs from aortic stenosis, mitral regurgitation, pulmonary hypertension, ventricular septal defects, and more. Exam findings are emphasized, along with distinguishing features between similar murmurs. A wide range of cardiac conditions are concisely summarized.
This document provides information on various endocrine diseases including their classification, causes, symptoms, investigations, diagnosis, complications, and treatment. It discusses types of diabetes (T1DM and T2DM), their defining features and management. It also covers diabetic ketoacidosis, hyperglycemic hyperosmolar state, and hypoglycemia. Further, it summarizes thyroid disorders like hyperthyroidism, hypothyroidism, and hyperparathyroidism along with their clinical presentation and management. The document is a comprehensive reference for classifying, diagnosing, and treating several important endocrine conditions.
Summary of differentiating features of neurological deficits (motor)Christiane Riedinger
This document provides information on distinguishing features of different types of weakness based on neurological examination findings. It describes patterns of tone, reflexes, muscle distribution and other findings that help localize the lesion and determine if it is upper motor neuron, lower motor neuron, extrapyramidal, brainstem, bulbar, pseudobulbar, cerebellar, spinal cord or neuromuscular junction related. Specific diseases are given as examples for each category.
1. The document outlines the contents and aims of a course on law and ethics for medical students preparing for finals. It covers topics like consent, confidentiality, medical errors, fertility treatment and issues at the end of life.
2. The course introduces key concepts in medical ethics and law, including ethical theories like deontology, consequentialism and virtue ethics. It also discusses principles of medical ethics from Beauchamp and Childress.
3. It describes the relationship between ethics, law and justice, and the role of human rights, responsibilities and conflicts of interest in healthcare.
Health protection involves protecting populations from infectious diseases, environmental threats, and other health hazards. It aims to control threats through policies like vaccinations, isolation procedures, and emergency protocols. Surveillance of health threats allows for rapid response to outbreaks. Gathering information, implementing prevention and control measures, and ongoing monitoring are key stages in health protection.
Public health aims to promote health and prevent disease in populations through systematic efforts. It covers health protection against infectious diseases and environmental threats, health improvement through education and legislation, and optimizing healthcare services. Some key areas of public health include using statistics and epidemiology to analyze population health data, assessing health needs and priorities, developing management and decision-making skills, and practicing health protection, improvement, screening and quality improvement. Public health also addresses challenges like children's health, aging populations, and health inequalities.
This document provides guidance on presenting patient examinations and findings concisely. It recommends including the most notable finding, important positives and negatives, differential diagnosis, and management plan in 3 sentences or less. Management should include any definitive diagnostic tests, immediate treatment needs, and general treatment options. Descriptions of lumps, skin lesions, murmurs and X-rays should be systematic and note key features like size, location, characteristics.
Contains bullet-point summary of questions to be asked in medical interview / consultation based on the presenting complaint or system. Contains additional information on clinical reasoning and developing a differential diagnosis
This document provides an outline of examination skills for various body systems, including:
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- Respiratory examination including inspection, percussion, auscultation, and examination from behind.
- Abdominal examination including inspection, palpation, auscultation, and examination of hernial orifices.
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This document provides an overview of renal pathology. It begins by outlining the topics to be covered, including organizing renal pathology, symptoms of renal pathology, kidney failure (acute vs chronic), sites of renal pathology in the glomeruli, tubules, interstitium and collecting system, and biochemical abnormalities. It then delves into each topic, defining and describing acute and chronic kidney failure, their causes and clinical phases. It also details the pathogenesis and histology of different types of glomerulonephritis and discusses pathology in the tubules, interstitium and collecting system. Throughout, it emphasizes the most common causes and clinical presentations of renal diseases.
This document provides an overview of cardiovascular pathology and focuses on myocardial infarction and endocarditis. It discusses the definition, etiology, pathogenesis, clinical features, investigations, and management of MI and endocarditis. It also presents an example case of a man experiencing chest pain who is found to have a dissecting aortic aneurysm.
The document summarizes key details about eukaryotic parasites that cause human disease. It describes several protozoan and metazoan parasites, including their lifecycles, epidemiology, infection characteristics, and pathology. Plasmodium falciparum, the causative agent of malaria, has a complex lifecycle involving mosquitos and humans and causes fever, headache, and organ failure. Toxoplasma gondii can cause ocular toxoplasmosis and fatal CNS disorders if the host is immuno-compromised. Several nematodes are described that have direct or indirect lifecycles involving eggs, larvae, and adult worms that can cause anaemia and gastrointestinal symptoms. Trematodes like Sch
This document discusses various classes of drugs used to treat inflammation and infection. It outlines different drug targets including enzymes, cytokines, receptors, calcium channels, DNA, protein synthesis, cell membranes, and energy production. Specific drugs are provided that inhibit these targets, such as NSAIDs, corticosteroids, antibiotics, and antifungals.
Maruthi Prithivirajan, Head of ASEAN & IN Solution Architecture, Neo4j
Get an inside look at the latest Neo4j innovations that enable relationship-driven intelligence at scale. Learn more about the newest cloud integrations and product enhancements that make Neo4j an essential choice for developers building apps with interconnected data and generative AI.
Programming Foundation Models with DSPy - Meetup SlidesZilliz
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TrustArc Webinar - 2024 Global Privacy SurveyTrustArc
How does your privacy program stack up against your peers? What challenges are privacy teams tackling and prioritizing in 2024?
In the fifth annual Global Privacy Benchmarks Survey, we asked over 1,800 global privacy professionals and business executives to share their perspectives on the current state of privacy inside and outside of their organizations. This year’s report focused on emerging areas of importance for privacy and compliance professionals, including considerations and implications of Artificial Intelligence (AI) technologies, building brand trust, and different approaches for achieving higher privacy competence scores.
See how organizational priorities and strategic approaches to data security and privacy are evolving around the globe.
This webinar will review:
- The top 10 privacy insights from the fifth annual Global Privacy Benchmarks Survey
- The top challenges for privacy leaders, practitioners, and organizations in 2024
- Key themes to consider in developing and maintaining your privacy program
In the rapidly evolving landscape of technologies, XML continues to play a vital role in structuring, storing, and transporting data across diverse systems. The recent advancements in artificial intelligence (AI) present new methodologies for enhancing XML development workflows, introducing efficiency, automation, and intelligent capabilities. This presentation will outline the scope and perspective of utilizing AI in XML development. The potential benefits and the possible pitfalls will be highlighted, providing a balanced view of the subject.
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The discussion will extend to how AI can be used to transform XML content. In particular, the focus will be on the use of AI XPath extension functions in XSLT, Schematron, Schematron Quick Fixes, or for XML content refactoring.
The presentation aims to deliver a comprehensive overview of AI usage in XML development, providing attendees with the necessary knowledge to make informed decisions. Whether you’re at the early stages of adopting AI or considering integrating it in advanced XML development, this presentation will cover all levels of expertise.
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For the full video of this presentation, please visit: https://www.edge-ai-vision.com/2024/06/building-and-scaling-ai-applications-with-the-nx-ai-manager-a-presentation-from-network-optix/
Robin van Emden, Senior Director of Data Science at Network Optix, presents the “Building and Scaling AI Applications with the Nx AI Manager,” tutorial at the May 2024 Embedded Vision Summit.
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HCL Notes and Domino License Cost Reduction in the World of DLAUpanagenda
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-and-domino-license-cost-reduction-in-the-world-of-dlau/
The introduction of DLAU and the CCB & CCX licensing model caused quite a stir in the HCL community. As a Notes and Domino customer, you may have faced challenges with unexpected user counts and license costs. You probably have questions on how this new licensing approach works and how to benefit from it. Most importantly, you likely have budget constraints and want to save money where possible. Don’t worry, we can help with all of this!
We’ll show you how to fix common misconfigurations that cause higher-than-expected user counts, and how to identify accounts which you can deactivate to save money. There are also frequent patterns that can cause unnecessary cost, like using a person document instead of a mail-in for shared mailboxes. We’ll provide examples and solutions for those as well. And naturally we’ll explain the new licensing model.
Join HCL Ambassador Marc Thomas in this webinar with a special guest appearance from Franz Walder. It will give you the tools and know-how to stay on top of what is going on with Domino licensing. You will be able lower your cost through an optimized configuration and keep it low going forward.
These topics will be covered
- Reducing license cost by finding and fixing misconfigurations and superfluous accounts
- How do CCB and CCX licenses really work?
- Understanding the DLAU tool and how to best utilize it
- Tips for common problem areas, like team mailboxes, functional/test users, etc
- Practical examples and best practices to implement right away
GraphSummit Singapore | The Art of the Possible with Graph - Q2 2024Neo4j
Neha Bajwa, Vice President of Product Marketing, Neo4j
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Communications Mining Series - Zero to Hero - Session 1DianaGray10
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• Why is it important?
• How can it help today’s business and the benefits
• Phases in Communication Mining
• Demo on Platform overview
• Q/A
UiPath Test Automation using UiPath Test Suite series, part 6DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 6. In this session, we will cover Test Automation with generative AI and Open AI.
UiPath Test Automation with generative AI and Open AI webinar offers an in-depth exploration of leveraging cutting-edge technologies for test automation within the UiPath platform. Attendees will delve into the integration of generative AI, a test automation solution, with Open AI advanced natural language processing capabilities.
Throughout the session, participants will discover how this synergy empowers testers to automate repetitive tasks, enhance testing accuracy, and expedite the software testing life cycle. Topics covered include the seamless integration process, practical use cases, and the benefits of harnessing AI-driven automation for UiPath testing initiatives. By attending this webinar, testers, and automation professionals can gain valuable insights into harnessing the power of AI to optimize their test automation workflows within the UiPath ecosystem, ultimately driving efficiency and quality in software development processes.
What will you get from this session?
1. Insights into integrating generative AI.
2. Understanding how this integration enhances test automation within the UiPath platform
3. Practical demonstrations
4. Exploration of real-world use cases illustrating the benefits of AI-driven test automation for UiPath
Topics covered:
What is generative AI
Test Automation with generative AI and Open AI.
UiPath integration with generative AI
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
HCL Notes und Domino Lizenzkostenreduzierung in der Welt von DLAUpanagenda
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-und-domino-lizenzkostenreduzierung-in-der-welt-von-dlau/
DLAU und die Lizenzen nach dem CCB- und CCX-Modell sind für viele in der HCL-Community seit letztem Jahr ein heißes Thema. Als Notes- oder Domino-Kunde haben Sie vielleicht mit unerwartet hohen Benutzerzahlen und Lizenzgebühren zu kämpfen. Sie fragen sich vielleicht, wie diese neue Art der Lizenzierung funktioniert und welchen Nutzen sie Ihnen bringt. Vor allem wollen Sie sicherlich Ihr Budget einhalten und Kosten sparen, wo immer möglich. Das verstehen wir und wir möchten Ihnen dabei helfen!
Wir erklären Ihnen, wie Sie häufige Konfigurationsprobleme lösen können, die dazu führen können, dass mehr Benutzer gezählt werden als nötig, und wie Sie überflüssige oder ungenutzte Konten identifizieren und entfernen können, um Geld zu sparen. Es gibt auch einige Ansätze, die zu unnötigen Ausgaben führen können, z. B. wenn ein Personendokument anstelle eines Mail-Ins für geteilte Mailboxen verwendet wird. Wir zeigen Ihnen solche Fälle und deren Lösungen. Und natürlich erklären wir Ihnen das neue Lizenzmodell.
Nehmen Sie an diesem Webinar teil, bei dem HCL-Ambassador Marc Thomas und Gastredner Franz Walder Ihnen diese neue Welt näherbringen. Es vermittelt Ihnen die Tools und das Know-how, um den Überblick zu bewahren. Sie werden in der Lage sein, Ihre Kosten durch eine optimierte Domino-Konfiguration zu reduzieren und auch in Zukunft gering zu halten.
Diese Themen werden behandelt
- Reduzierung der Lizenzkosten durch Auffinden und Beheben von Fehlkonfigurationen und überflüssigen Konten
- Wie funktionieren CCB- und CCX-Lizenzen wirklich?
- Verstehen des DLAU-Tools und wie man es am besten nutzt
- Tipps für häufige Problembereiche, wie z. B. Team-Postfächer, Funktions-/Testbenutzer usw.
- Praxisbeispiele und Best Practices zum sofortigen Umsetzen
Observability Concepts EVERY Developer Should Know -- DeveloperWeek Europe.pdfPaige Cruz
Monitoring and observability aren’t traditionally found in software curriculums and many of us cobble this knowledge together from whatever vendor or ecosystem we were first introduced to and whatever is a part of your current company’s observability stack.
While the dev and ops silo continues to crumble….many organizations still relegate monitoring & observability as the purview of ops, infra and SRE teams. This is a mistake - achieving a highly observable system requires collaboration up and down the stack.
I, a former op, would like to extend an invitation to all application developers to join the observability party will share these foundational concepts to build on:
Goodbye Windows 11: Make Way for Nitrux Linux 3.5.0!SOFTTECHHUB
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The propagation of action potentials along the axon.
1. Christiane – HOM2 1
Depolarisation: Perturbation of the membrane potential towards a larger (i.e.
more positive) value.
How is an action potential propagated along the axon?
An action potential is a short-lasting spike-like change in the membrane potential that
is passed along an axon as a result of a trigger/stimulus (Figure 1). The trigger can be
a small change in charge distribution across a membrane caused by mechanically-
gated ion channels responding to mechanical stress, or by the action of
neurotransmitters on ligand-gated ion channels. This initial depolarisation is sensed
by a small amount of voltage-gated Na+ channels, causing them to open. Na+ ions
can now flow into the cell along their concentration gradient, changing the charge
distribution and hence causing an even bigger depolarisation of the membrane. This in
turn results in more Na+ channels to open, increasing the Na+-permeability of the
cell.
If the initial stimulus is large enough and the chain-reaction of opening Na+ channels
affecting their neighbours occurs quick enough, then a positive feedback-loop is
initiated, leading to a very fast increase in membrane potential (area 1 in figure 1).
The permeability to Na+ becomes so large that the value of the overall potential in the
area where the action potential occurs almost reaches that of a cell solely permeable
to Na+.
As a result of the depolarisation of the membrane, voltage-gated K+ channels also
start to open, but with a slight delay compared to the Na+ channels. Once opened, K+
ions start to flow out of the cell along their concentration gradient, which is larger
than that of Na+ (K+ inside/outside = 20/1, Na+ inside/outside = 1/9). This is how the
flux of K+ ions can quickly catch up with the Na+ flux. In fact, the Na+ flux is even
outweighed by the K+ flux since Na+ channels start to close at this point. The closure
of Na+ channels is purely time-dependent and once they are closed, Na+ channels
remain inactivated for 10ms even when the resting potential has been re-established.
Hence, after the initial rise of the membrane potential towards the value of Na+, the
membrane potential now moves quickly towards the value of K+, as a result of the
membrane now being primarily permeable to K+ ions (see area 2. figure 1). As the
closure of the K+ channels is voltage-dependent, K+ channels start to close at this
2. Christiane – HOM2 2
point and the membrane potential then returns back to its resting value, which still lies
relatively close to the potential of K+ alone (area 3. figure 1).
Plot of the action potential
E (Na+)
1. 2. 3.
E (K+)
Figure 1. Adapted from http://courses.cit.cornell.edu/bionb441/FinalProjects/f2006/sjj26/491_SJJ26/Action_Potential.JPG
An action potential only occurs in a limited area of the cell membrane, but the
changes in membrane potential at the edges of this area are enough to initiate another
action potential in a neighbouring space, which then gives rise to another action
potential further down the axon and so forth. This is how action potentials are
propagated along the length of the axon. The inability of Na+ channels to re-open
after the first action potential was fired ensures that the wave of action potentials
travels only in one direction, that is away from the initial area of depolarisation.
Passing on small perturbations of the membrane potential across larger distances in an
axon is difficult as the signal decays across the length of the membrane. This
(exponential) decay is a result of leakage of the current transmitting the depolarisation
along the axon to the surrounding areas. The action potential is a good way to prevent
this loss of signal along the axon as each individual action potential recovers the
strength of the original signal. As long as the threshold is overcome, it does not matter
what the absolute size of the initial depolarisation was (all-or-nothing law), the action
potential will occur to completion. In case of a failed initialisation without action
potential (yellow line in figure 1), the signal decays along the length of the
3. Christiane – HOM2 3
membrane, the cell eventually returns to its resting state. This is known as passive or
electrotonic potential. This way of signalling is not effective across large distances
and is therefore only employed by small neurones, some of which are located in the
retina of the eye. The decay of the signal as a function of distance is described by the
length constant, which is the distance at which the voltage has decayed to
approximally 1/3 of the initial value. If the distance across which the signal needs to
be transmitted lies below the length constant, then passive transport is appropriate. If
the distance is larger, then active transport using action potentials is required.
Nice movie of propagation of action potentials in myelinated and unmyelinated
nerves: http://www.blackwellpublishing.com/matthews/actionp.html
4. Christiane – HOM2 4
What factors affect the velocity of conduction?
The speed with which a signal is transmitted along an axon is quite important, as the
quick response to a stimulus may decide over life and death of an animal exposed to a
threat. This is why several ways to accelerate nerve impulse conduction have been
developed throughout evolution:
One way to increase the speed of conduction is through insulation of nerve fibres by
myelination. Myelin sheaths are areas in which the cell membrane of nerve-
supporting glial cells (Schwann cells in peripheral nerves or oligodendrytes in the
CNS) is wrapped around the axons. This enlarges the thickness of the nerve fibre
wall, and thereby increases the electrical (transverse) resistance across the
membrane (Resistance increases as a wire becomes longer). Charges can therefore
more easily flow longitudinally, which is the desired direction. Furthermore, areas of
myelination don’t contain Na+ channels, which further increases the transverse
resistance, ensuring that even more ions causing depolarisation can flow
longitudinally along the axon.
Myelination also reduces the capacitance of the membrane, as this is inversely
proportional to the thickness of the insulating layer in a circuit. Since capacitance is
defined as charge over voltage, a lower capacitance for a set number of charges on
each side of the membrane results in a larger potential difference established.
The combination of these two effects increase the speed with which potential
differences are passed along the axon, as well as the range with which an action
potential can affect neighbouring areas. Assuming that currents passing in the
longitudinal direction move faster than voltage-induced membrane channels open
(requires protein rearrangements which happen on a slower timescale than ions move
in solution), it is probably in the interest of speed to fire fewer action potentials and
extend the range of passive propagation of currents.
The myelinated areas are interrupted by so-called “Nodes of Ranvier”, small stretches
of uninsolated axon with a high concentration of Na+ channels. When a
depolarisation current reaches a Node of Ranvier, a new action potential is generated
which is then quickly passed through the next area of myelin insulation to the
adjacent Node of Ranvier. This is called saltatory (“jumping”) conduction and
provides an excellent way to speed up the propagation of the action potential while
5. Christiane – HOM2 5
conserving metabolic energy: Using too many Na+ channels would require a lot of
ATP to pump the Na+ back out of the cell against its concentration gradient.
Another way in which faster neuronal communication has evolved is through
enlargement of the axon diameter, i.e. the interior compartment containing the
axoplasm. This is also called “axonal gigantism”. Just like in a metal cable that
conducts electricity, a wire with a larger diameter results in a drop in longitudinal
resistance, which ensures that the depolarisation can be passed on more efficiently.
In summary, the following parameters affect the speed of conduction:
1. Leakage of ions: decreases the longitudinal flow of current and is linked to the
resistance of the cell membrane as well as its capacitance. This is compensated
by myelination.
2. The thickness of the membrane: affects its resistance and its capacitance. This
is again optimised by myelination.
3. The inside diameter of the axon containing the axoplasm: This affects the
longitudinal resistance and can be optimised by axon gigantism.
Extracellular matrix
R↑↓ needs to be large
C↑↓ needs to be small
Myelin layers
Axon membrane
Na+ channels
Q Longitudinal flow of charges needs to be
optimised for signal propagation.
R↔ needs to be small
Q, I ↔ needs to be large
Axoplasm = intracellular matrix
6. Christiane – HOM2 6
Useful plot: Diameter of diameter versus conduction velocity achieved
Myelinated = linear
velocity Non-myelinated
velocity higher
for a diameter unmyelinated
below 1um! V ~ √diameter
For diameters
larger than 1um,
myelination
increases the
speed of
conduction!
1µm diameter
(myelination!!!)
in organisms with myelin:
- if diameter > 1um myelinated
- if diameter < 1um unmyelinated
- some exceptions in the brain where neuron density is so high (protect from
extracellular environment)