1. Sensation from the body travels up the spinal cord or trigeminal nerve to the thalamus where nerve fibers cross sides. It is then transmitted to the postcentral gyrus in the parietal lobe for analysis, storage as memory, localization, and production of complex sensations.
2. The motor system is involved in movement production through stimulation of agonist muscles and inhibition of antagonists, along with coordination and postural adjustments. It requires planning in frontal lobe areas and execution through motor neurons of the spinal cord and brainstem.
3. The pyramidal tract transmits signals from the motor cortex to lower motor neurons, controlling distal muscles. Extrapyramidal tracts originate in the brainstem and
This document discusses the human sensory system and how sensory information is processed in the nervous system. It covers:
1. How sensory receptors detect different types of energy (light, sound, touch, temperature) and convert it into action potentials.
2. How action potentials travel along sensory neurons to the spinal cord and brain for analysis. Sensory information can be urgent and travel along myelinated fibers.
3. How the number and distribution of receptors impacts our ability to detect and differentiate stimuli.
4. How summation (temporal and spatial) of excitatory and inhibitory postsynaptic potentials integrates sensory information at the cellular level in the central nervous system.
The document discusses reflexes and the nervous system. It defines reflexes as rapid automatic responses to specific stimuli. It describes the five steps in a neural reflex arc: 1) stimulus activates a receptor, 2) activation of a sensory neuron, 3) information processing in the central nervous system, 4) activation of a motor neuron, 5) response of a peripheral effector. Reflexes can be classified based on their development, processing site, response type, and complexity of the neural circuit involved. The stretch tendon reflex is provided as a detailed example of a polysynaptic reflex. The basal ganglia are also summarized as subcortical structures that receive input from and return output to the cerebral cortex to affect motor activity.
The document discusses various types of sensations detected by the nervous system including pain, touch, proprioception, vibration, and thermal sensations. It describes:
1) The pathways for each sensation from receptors to the central nervous system, including the roles of first, second, and third order neurons.
2) Characteristics of different sensations such as poorly localized deep pain versus well-localized superficial pain.
3) Structures involved in each pathway such as dorsal root ganglia, dorsal columns, spinothalamic tracts, and various brain regions.
The document summarizes key aspects of the cerebellum and brainstem. It discusses how the cerebellum consists of 300 million functional units arranged in cerebellar nuclei that coordinate movement. It also describes how the brainstem is important as it contains sensory and motor tracts, respiratory centers, and the reticular activating system. Finally, it provides an overview of the 12 cranial nerves, outlining their functions and origins/destinations.
The document summarizes several topics related to the nervous system:
1. The brain and spinal cord are protected by bones, cushioning, and membranes like the meninges and cerebrospinal fluid.
2. The brainstem regulates arousal and sleep through structures like the reticular formation. Sleep involves two types: non-REM and REM.
3. Circadian rhythms are regulated by a biological clock in the hypothalamus synchronized to light/dark cycles.
4. Emotions involve limbic structures like the amygdala interacting with sensory areas, while memory involves the hippocampus and cortex.
The document discusses the structure and function of the human nervous system. It describes that the nervous system consists of the central nervous system (CNS), which includes the brain and spinal cord, and the peripheral nervous system (PNS), which carries information into and out of the CNS. Neurons are the basic functional units of the nervous system that communicate via electrical and chemical signals to integrate sensory input and coordinate motor output.
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.
The document provides information about the autonomic nervous system (ANS). It describes the ANS as having two main divisions - the sympathetic and parasympathetic nervous systems. The sympathetic system prepares the body for "fight or flight" responses, while the parasympathetic system allows for "rest and digest" functions. Key differences between the two divisions are described, including their origins in the spinal cord/brain and targets in the body. The pathways of preganglionic and postganglionic neurons, as well as autonomic ganglia, are outlined. Neurotransmitters and receptors of each division are also detailed.
This document discusses the human sensory system and how sensory information is processed in the nervous system. It covers:
1. How sensory receptors detect different types of energy (light, sound, touch, temperature) and convert it into action potentials.
2. How action potentials travel along sensory neurons to the spinal cord and brain for analysis. Sensory information can be urgent and travel along myelinated fibers.
3. How the number and distribution of receptors impacts our ability to detect and differentiate stimuli.
4. How summation (temporal and spatial) of excitatory and inhibitory postsynaptic potentials integrates sensory information at the cellular level in the central nervous system.
The document discusses reflexes and the nervous system. It defines reflexes as rapid automatic responses to specific stimuli. It describes the five steps in a neural reflex arc: 1) stimulus activates a receptor, 2) activation of a sensory neuron, 3) information processing in the central nervous system, 4) activation of a motor neuron, 5) response of a peripheral effector. Reflexes can be classified based on their development, processing site, response type, and complexity of the neural circuit involved. The stretch tendon reflex is provided as a detailed example of a polysynaptic reflex. The basal ganglia are also summarized as subcortical structures that receive input from and return output to the cerebral cortex to affect motor activity.
The document discusses various types of sensations detected by the nervous system including pain, touch, proprioception, vibration, and thermal sensations. It describes:
1) The pathways for each sensation from receptors to the central nervous system, including the roles of first, second, and third order neurons.
2) Characteristics of different sensations such as poorly localized deep pain versus well-localized superficial pain.
3) Structures involved in each pathway such as dorsal root ganglia, dorsal columns, spinothalamic tracts, and various brain regions.
The document summarizes key aspects of the cerebellum and brainstem. It discusses how the cerebellum consists of 300 million functional units arranged in cerebellar nuclei that coordinate movement. It also describes how the brainstem is important as it contains sensory and motor tracts, respiratory centers, and the reticular activating system. Finally, it provides an overview of the 12 cranial nerves, outlining their functions and origins/destinations.
The document summarizes several topics related to the nervous system:
1. The brain and spinal cord are protected by bones, cushioning, and membranes like the meninges and cerebrospinal fluid.
2. The brainstem regulates arousal and sleep through structures like the reticular formation. Sleep involves two types: non-REM and REM.
3. Circadian rhythms are regulated by a biological clock in the hypothalamus synchronized to light/dark cycles.
4. Emotions involve limbic structures like the amygdala interacting with sensory areas, while memory involves the hippocampus and cortex.
The document discusses the structure and function of the human nervous system. It describes that the nervous system consists of the central nervous system (CNS), which includes the brain and spinal cord, and the peripheral nervous system (PNS), which carries information into and out of the CNS. Neurons are the basic functional units of the nervous system that communicate via electrical and chemical signals to integrate sensory input and coordinate motor output.
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.
The document provides information about the autonomic nervous system (ANS). It describes the ANS as having two main divisions - the sympathetic and parasympathetic nervous systems. The sympathetic system prepares the body for "fight or flight" responses, while the parasympathetic system allows for "rest and digest" functions. Key differences between the two divisions are described, including their origins in the spinal cord/brain and targets in the body. The pathways of preganglionic and postganglionic neurons, as well as autonomic ganglia, are outlined. Neurotransmitters and receptors of each division are also detailed.
This document discusses sensory and motor pathways in the human body. It begins by listing the key learning outcomes, which include describing sensory receptors, pathways in the spinal cord and brain, motor neurons and tracts, and the corticospinal tract. It then discusses myelinated and non-myelinated nerve fibers, how they conduct impulses, and their roles. The document proceeds to explain sensory pathways from receptors to the brain, motor pathways from the brain to muscles, and provides diagrams of sensory and motor tracts in the spinal cord. It concludes by describing functions of sensory and motor neurons.
The document provides an overview of neurophysiology, the study of the functioning of the nervous system. It describes the basic structure and components of neurons, including the cell body, dendrites, axon, synapse, and myelin sheath. It discusses the types of neurons, including sensory and motor neurons, and how they differ in structure and function. The document also explains how neurons transmit signals through electrical and chemical processes, including the generation and propagation of action potentials along axons and the transmission of signals across synapses using neurotransmitters.
The nervous system is a highly organized network of billions of nerve cells that functions as the control center of the body. It has two main divisions - the central nervous system comprising the brain and spinal cord, and the peripheral nervous system outside of these. Nerve cells called neurons are specialized to conduct electrical signals called action potentials that allow communication within the nervous system. Neurons have cell bodies and long processes called axons that transmit signals. They communicate with other neurons at junctions called synapses using chemical messenger molecules. The coordinated functions of sensation, integration and response enabled by this neuronal signaling allow the nervous system to monitor and control all bodily functions.
The nervous system has three main functions: sensory, integration, and motor. It is divided into the central nervous system (CNS; brain and spinal cord) and peripheral nervous system (PNS). The CNS contains neurons and neuroglia. Neuroglia provide support and protection for neurons. There are two types of neurons - sensory neurons transmit sensory information to the CNS, and motor neurons transmit signals from the CNS to effectors like muscles. Neurons communicate via electrical or chemical synapses using neurotransmitters like acetylcholine, GABA, glutamate, and catecholamines.
The document summarizes key aspects of neurophysiology, including the motor system, corticospinal system, lower motor neurons, extrapyramidal system, cerebellum, sensory system, reflex activities, and control of micturition. It describes the components and functions of these systems, as well as signs associated with lesions in different parts of the nervous system.
The document summarizes the organization and function of the nervous system. It discusses how the nervous system is divided into the central nervous system (CNS) and peripheral nervous system (PNS). It also describes the basic components of neurons, including the cell body, dendrites, axon, and myelin sheath. It explains how neurons communicate via graded potentials and action potentials in response to stimuli and how synapses facilitate communication between neurons.
The document summarizes the main parts and functions of the human nervous system. It discusses the brain, spinal cord, neurons, and different systems like the somatic and autonomic nervous systems. It also briefly describes several neurological disorders like meningitis, Parkinson's disease, and polio.
The spinal cord or medulla is part of the central nervous system that extends from the foramen magnum to the lower back and has a cervical and lumbar enlargement. It has 31 segments and is surrounded by meninges. Internally, it contains grey matter in an H-shaped column with neuronal groups, and white matter organized into dorsal, lateral, and ventral funiculi containing ascending and descending tracts. The spinal cord transmits information between the brain and body and facilitates reflexes via its grey matter.
The nervous system consists of neurons and neuroglial cells. Neurons transmit nerve impulses through electrical and chemical signals. The neuron has a cell body, dendrites which receive signals, and an axon which transmits signals. Schwann cells wrap around axons and produce myelin sheaths for insulation and faster signal transmission. The nervous system has sensory, inter, and motor neurons and performs functions like receiving information and transmitting instructions. Diseases can disrupt myelin sheaths and impair signaling.
The autonomic nervous system (ANS) controls involuntary body functions through two divisions - the sympathetic and parasympathetic systems. The sympathetic division uses the neurotransmitter norepinephrine to activate the fight or flight response. The parasympathetic division uses acetylcholine primarily to restore and maintain bodily functions at rest. Both systems work in opposition through receptors to precisely control organs like the heart, lungs, and digestive system. Diseases like Horner's syndrome involving the ANS can impact functions like sweating and eye movement. Tests of the ANS evaluate responses like heart rate and blood pressure with activities like breathing and standing.
The document provides an overview of the nervous system, including its general functions of sensation, integration, and motor response. It describes the main cell types of the nervous system as neurons, which perform the major functions, and neuroglia, which play a supporting role. Neurons are classified as afferent, interneurons, or efferent. The central nervous system consists of the brain and spinal cord, which contain gray matter for signal processing and white matter for tract formation. The peripheral nervous system connects to the central nervous system via afferent and efferent tracts in the spinal cord.
The motor system consists of upper motor neurons originating in the motor cortex and lower motor neurons originating in the spinal cord. The motor cortex is located in the frontal lobe and contains a somatotopic map called the motor homunculus. Primary motor areas like the primary motor cortex directly control muscle contraction, while secondary areas like the premotor cortex plan movements. Upper motor neurons descend through tracts like the corticospinal tract to synapse on lower motor neurons, which innervate muscles. Damage to different parts of the motor system can cause muscle weakness or changes in tone like spasticity or flaccidity.
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 central nervous system consists of the brain and spinal cord. The brain is divided into the cerebrum, brain stem, and cerebellum. The cerebrum is made up of two hemispheres and controls functions like reasoning and movement. The brain stem regulates vital functions. The cerebellum coordinates movement and balance. The spinal cord transmits signals between the brain and body. Glial cells support neurons. The blood-brain barrier protects the brain from toxins in blood circulation.
This document discusses sensory receptors and somatic sensation. It covers:
1. The 5 main types of sensory receptors and what they detect.
2. How receptor potentials are generated and transmitted as action potentials.
3. The pathways that somatic signals take in the central nervous system.
4. Areas of the brain involved in processing somatic sensation like the somatosensory cortex.
Dental lecture: brain stem, ascending and descending pathways vajira54
This document provides an overview of neurophysiology lecture topics related to the brainstem and motor control. It discusses the role of the brainstem, including structures like the reticular formation, in functions such as consciousness, motor control, and reflexes. It describes ascending and descending tracts that are involved in sensory and motor pathways. These include dorsal column-medial lemniscus and spinothalamic tracts for somatosensation, as well as corticospinal and extrapyramidal tracts for motor control. The maintenance of posture, equilibrium and muscle tone involves complex integration of sensory inputs and postural reflexes at spinal, brainstem and cortical levels.
This document provides an overview of the nervous system, including its main components and functions. It discusses the central nervous system (CNS), which includes the brain and spinal cord. It also discusses the peripheral nervous system (PNS), which is divided into the somatic and autonomic nervous systems. The autonomic nervous system has two divisions - the sympathetic and parasympathetic nervous systems, which work in opposition to control involuntary body functions. Key cell types and the structures of the brain, spinal cord, and nerves are also summarized.
This document summarizes the key components of the human sensory system. It describes how sensory information is received by receptors, transmitted through neurons in the peripheral and central nervous systems, and integrated and processed in the brain. Specifically, it discusses:
1) The pathways for different sensory modalities from receptors to the spinal cord and brain, including pain/temperature, touch, and proprioception.
2) The ascending tracts that transmit sensory information from the spinal cord to the brain, such as the lateral spinothalamic, anterior spinothalamic, and posterior columns.
3) Common lesions that affect sensory pathways and how they impact sensation, such as hemisection of the spinal cord or damage to
This document provides an overview of the structure and function of the nervous system. It begins with an introduction to the central nervous system (CNS) and peripheral nervous system. It then describes the main divisions and components of the CNS in detail, including the brain stem, cerebellum, diencephalon, and telencephalon. It discusses the protection mechanisms of the CNS, including the skull, meninges, blood-brain barrier, and cerebrospinal fluid. Finally, it provides an overview of neurons, glial cells, and classifications of neurons.
1. There are two main types of somatic motor pathways - direct and indirect. Direct pathways transmit signals from the cerebral cortex to lower motor neurons, while indirect pathways involve additional structures like the basal ganglia and cerebellum.
2. Direct pathways include the corticospinal and corticobulbar tracts. Indirect pathways include the rubrospinal, tectospinal, vestibulospinal, lateral reticulospinal, and medial reticulospinal tracts.
3. Together these pathways coordinate voluntary and involuntary muscle movements through connections with lower motor neurons in the brainstem and spinal cord.
The document provides information about the nervous system. It discusses that the nervous system is divided into the central nervous system (CNS) and peripheral nervous system (PNS). The CNS consists of the brain and spinal cord. The PNS includes the autonomic nervous system and relays information between the CNS and the body. Within the CNS, the brain is the center of neural activity and integration. Neurons are the basic functional units that carry and transmit electrochemical signals throughout the nervous system.
This document discusses sensory and motor pathways in the human body. It begins by listing the key learning outcomes, which include describing sensory receptors, pathways in the spinal cord and brain, motor neurons and tracts, and the corticospinal tract. It then discusses myelinated and non-myelinated nerve fibers, how they conduct impulses, and their roles. The document proceeds to explain sensory pathways from receptors to the brain, motor pathways from the brain to muscles, and provides diagrams of sensory and motor tracts in the spinal cord. It concludes by describing functions of sensory and motor neurons.
The document provides an overview of neurophysiology, the study of the functioning of the nervous system. It describes the basic structure and components of neurons, including the cell body, dendrites, axon, synapse, and myelin sheath. It discusses the types of neurons, including sensory and motor neurons, and how they differ in structure and function. The document also explains how neurons transmit signals through electrical and chemical processes, including the generation and propagation of action potentials along axons and the transmission of signals across synapses using neurotransmitters.
The nervous system is a highly organized network of billions of nerve cells that functions as the control center of the body. It has two main divisions - the central nervous system comprising the brain and spinal cord, and the peripheral nervous system outside of these. Nerve cells called neurons are specialized to conduct electrical signals called action potentials that allow communication within the nervous system. Neurons have cell bodies and long processes called axons that transmit signals. They communicate with other neurons at junctions called synapses using chemical messenger molecules. The coordinated functions of sensation, integration and response enabled by this neuronal signaling allow the nervous system to monitor and control all bodily functions.
The nervous system has three main functions: sensory, integration, and motor. It is divided into the central nervous system (CNS; brain and spinal cord) and peripheral nervous system (PNS). The CNS contains neurons and neuroglia. Neuroglia provide support and protection for neurons. There are two types of neurons - sensory neurons transmit sensory information to the CNS, and motor neurons transmit signals from the CNS to effectors like muscles. Neurons communicate via electrical or chemical synapses using neurotransmitters like acetylcholine, GABA, glutamate, and catecholamines.
The document summarizes key aspects of neurophysiology, including the motor system, corticospinal system, lower motor neurons, extrapyramidal system, cerebellum, sensory system, reflex activities, and control of micturition. It describes the components and functions of these systems, as well as signs associated with lesions in different parts of the nervous system.
The document summarizes the organization and function of the nervous system. It discusses how the nervous system is divided into the central nervous system (CNS) and peripheral nervous system (PNS). It also describes the basic components of neurons, including the cell body, dendrites, axon, and myelin sheath. It explains how neurons communicate via graded potentials and action potentials in response to stimuli and how synapses facilitate communication between neurons.
The document summarizes the main parts and functions of the human nervous system. It discusses the brain, spinal cord, neurons, and different systems like the somatic and autonomic nervous systems. It also briefly describes several neurological disorders like meningitis, Parkinson's disease, and polio.
The spinal cord or medulla is part of the central nervous system that extends from the foramen magnum to the lower back and has a cervical and lumbar enlargement. It has 31 segments and is surrounded by meninges. Internally, it contains grey matter in an H-shaped column with neuronal groups, and white matter organized into dorsal, lateral, and ventral funiculi containing ascending and descending tracts. The spinal cord transmits information between the brain and body and facilitates reflexes via its grey matter.
The nervous system consists of neurons and neuroglial cells. Neurons transmit nerve impulses through electrical and chemical signals. The neuron has a cell body, dendrites which receive signals, and an axon which transmits signals. Schwann cells wrap around axons and produce myelin sheaths for insulation and faster signal transmission. The nervous system has sensory, inter, and motor neurons and performs functions like receiving information and transmitting instructions. Diseases can disrupt myelin sheaths and impair signaling.
The autonomic nervous system (ANS) controls involuntary body functions through two divisions - the sympathetic and parasympathetic systems. The sympathetic division uses the neurotransmitter norepinephrine to activate the fight or flight response. The parasympathetic division uses acetylcholine primarily to restore and maintain bodily functions at rest. Both systems work in opposition through receptors to precisely control organs like the heart, lungs, and digestive system. Diseases like Horner's syndrome involving the ANS can impact functions like sweating and eye movement. Tests of the ANS evaluate responses like heart rate and blood pressure with activities like breathing and standing.
The document provides an overview of the nervous system, including its general functions of sensation, integration, and motor response. It describes the main cell types of the nervous system as neurons, which perform the major functions, and neuroglia, which play a supporting role. Neurons are classified as afferent, interneurons, or efferent. The central nervous system consists of the brain and spinal cord, which contain gray matter for signal processing and white matter for tract formation. The peripheral nervous system connects to the central nervous system via afferent and efferent tracts in the spinal cord.
The motor system consists of upper motor neurons originating in the motor cortex and lower motor neurons originating in the spinal cord. The motor cortex is located in the frontal lobe and contains a somatotopic map called the motor homunculus. Primary motor areas like the primary motor cortex directly control muscle contraction, while secondary areas like the premotor cortex plan movements. Upper motor neurons descend through tracts like the corticospinal tract to synapse on lower motor neurons, which innervate muscles. Damage to different parts of the motor system can cause muscle weakness or changes in tone like spasticity or flaccidity.
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 central nervous system consists of the brain and spinal cord. The brain is divided into the cerebrum, brain stem, and cerebellum. The cerebrum is made up of two hemispheres and controls functions like reasoning and movement. The brain stem regulates vital functions. The cerebellum coordinates movement and balance. The spinal cord transmits signals between the brain and body. Glial cells support neurons. The blood-brain barrier protects the brain from toxins in blood circulation.
This document discusses sensory receptors and somatic sensation. It covers:
1. The 5 main types of sensory receptors and what they detect.
2. How receptor potentials are generated and transmitted as action potentials.
3. The pathways that somatic signals take in the central nervous system.
4. Areas of the brain involved in processing somatic sensation like the somatosensory cortex.
Dental lecture: brain stem, ascending and descending pathways vajira54
This document provides an overview of neurophysiology lecture topics related to the brainstem and motor control. It discusses the role of the brainstem, including structures like the reticular formation, in functions such as consciousness, motor control, and reflexes. It describes ascending and descending tracts that are involved in sensory and motor pathways. These include dorsal column-medial lemniscus and spinothalamic tracts for somatosensation, as well as corticospinal and extrapyramidal tracts for motor control. The maintenance of posture, equilibrium and muscle tone involves complex integration of sensory inputs and postural reflexes at spinal, brainstem and cortical levels.
This document provides an overview of the nervous system, including its main components and functions. It discusses the central nervous system (CNS), which includes the brain and spinal cord. It also discusses the peripheral nervous system (PNS), which is divided into the somatic and autonomic nervous systems. The autonomic nervous system has two divisions - the sympathetic and parasympathetic nervous systems, which work in opposition to control involuntary body functions. Key cell types and the structures of the brain, spinal cord, and nerves are also summarized.
This document summarizes the key components of the human sensory system. It describes how sensory information is received by receptors, transmitted through neurons in the peripheral and central nervous systems, and integrated and processed in the brain. Specifically, it discusses:
1) The pathways for different sensory modalities from receptors to the spinal cord and brain, including pain/temperature, touch, and proprioception.
2) The ascending tracts that transmit sensory information from the spinal cord to the brain, such as the lateral spinothalamic, anterior spinothalamic, and posterior columns.
3) Common lesions that affect sensory pathways and how they impact sensation, such as hemisection of the spinal cord or damage to
This document provides an overview of the structure and function of the nervous system. It begins with an introduction to the central nervous system (CNS) and peripheral nervous system. It then describes the main divisions and components of the CNS in detail, including the brain stem, cerebellum, diencephalon, and telencephalon. It discusses the protection mechanisms of the CNS, including the skull, meninges, blood-brain barrier, and cerebrospinal fluid. Finally, it provides an overview of neurons, glial cells, and classifications of neurons.
1. There are two main types of somatic motor pathways - direct and indirect. Direct pathways transmit signals from the cerebral cortex to lower motor neurons, while indirect pathways involve additional structures like the basal ganglia and cerebellum.
2. Direct pathways include the corticospinal and corticobulbar tracts. Indirect pathways include the rubrospinal, tectospinal, vestibulospinal, lateral reticulospinal, and medial reticulospinal tracts.
3. Together these pathways coordinate voluntary and involuntary muscle movements through connections with lower motor neurons in the brainstem and spinal cord.
The document provides information about the nervous system. It discusses that the nervous system is divided into the central nervous system (CNS) and peripheral nervous system (PNS). The CNS consists of the brain and spinal cord. The PNS includes the autonomic nervous system and relays information between the CNS and the body. Within the CNS, the brain is the center of neural activity and integration. Neurons are the basic functional units that carry and transmit electrochemical signals throughout the nervous system.
The document summarizes the descending motor tracts that transmit signals from the brain to lower motor neurons and muscles. It focuses on the pyramidal tracts, including the corticospinal tract which controls voluntary limb movement, and corticobulbar tract which controls head and neck muscles. The corticospinal tract originates in motor areas of the cortex and projects through the brainstem and spinal cord. The corticobulbar tract projects to motor nuclei controlling cranial nerves.
This document provides an overview of the nervous system. It begins by defining the nervous system and its main functions of receiving sensory input, integrating information, and generating motor output. It then describes the structure and function of the main parts of the human nervous system, including the central nervous system (brain and spinal cord), and peripheral nervous system. Key topics covered include the structure and function of the brain lobes and other brain regions, neurons, nerve impulses, and reflexes.
The spinal cord carries nerve signals throughout the body to control movements and functions as well as report senses to the brain. It has 31 pairs of spinal nerves that branch into dorsal roots carrying sensory fibers and ventral roots carrying motor fibers. The autonomic nervous system, including the sympathetic and parasympathetic systems, regulates involuntary body functions like breathing, digestion and heart rate through pathways from the spinal cord and brain to organs and tissues.
The document summarizes the structure and function of the nervous system. It describes how the nervous system is divided into the central nervous system (brain and spinal cord) and peripheral nervous system. It explains the types of neurons (sensory, motor, interneurons), how impulses are transmitted across synapses, and the functions of major parts of the brain and spinal cord, including processing sensory information and controlling movement. It also outlines how nerves, tracts and cranial nerves connect the CNS to the rest of the body.
The cerebellum and basal ganglia play important roles in motor control and coordination. The cerebellum helps control the timing, smoothness, and intensity of muscle movements. It receives sensory feedback and compares actual movements to planned movements, sending corrections back to the motor system. The basal ganglia help plan and control complex patterns of muscle movement. The cerebellum has distinct input and output pathways and its Purkinje cells provide inhibitory signals that help regulate the output of deep nuclear cells and coordinate movement.
The document provides an overview of the brain and its functions. It discusses that the brain is composed of different parts that work together to control movements, thoughts, emotions and behaviors. It also notes that the brain receives support and protection from other body parts like blood vessels, the skull and membranes. The document then describes the main sections of the brain - the hindbrain, midbrain and forebrain - and provides details on the roles and structures within each section. It also discusses neurons, neurotransmitters and how they facilitate communication within the brain and nervous system.
The document summarizes the motor system, including voluntary and involuntary motor functions. It describes various reflexes like the stretch reflex and their components. The motor cortex and corticospinal tract are discussed. The role of upper motor neurons, lower motor neurons, and extrapyramidal tracts in motor control is explained. Various tests to examine the motor system are also mentioned.
This document discusses the descending tracts of the spinal cord. It begins by describing the lobes of the cerebral cortex and key motor areas like the primary motor cortex, premotor cortex, and frontal eye fields. It then discusses the major descending tracts that originate from these motor areas and other supraspinal structures. The primary tracts discussed are the corticospinal, corticobulbar, rubrospinal, vestibulospinal, reticulospinal, tectospinal, and olivospinal tracts. It concludes by contrasting the signs of upper motor neuron lesions, which affect the descending tracts, versus lower motor neuron lesions, which affect the anterior horn cells.
The somatomotor system is organized in a 3-tier hierarchical system, with the highest level in the cerebral cortex, middle level in subcortical structures like the basal ganglia and cerebellum, and lowest level in the spinal cord and brainstem. The motor cortex plans voluntary movements and issues commands to the spinal cord via pyramidal tracts. Basal ganglia and cerebellum help coordinate skilled movements and maintain posture and tone. Spinal motor neurons innervate skeletal muscles to enable movement. Proprioceptive feedback integrates signals across these levels of the motor system.
The document provides an overview of the nervous system, including:
- The central nervous system (CNS) which includes the brain and spinal cord.
- The peripheral nervous system (PNS) which includes nerves and ganglia outside the CNS.
- How neurons transmit signals via electrical and chemical processes.
- Key parts of the human brain like the cerebrum, cerebellum, and brain stem.
- Common neurological disorders like Alzheimer's, Parkinson's, depression and drug addiction.
The nervous system consists of the brain, spinal cord, sensory organs, and all of the nerves that connect these organs with the rest of the body. Together, these organs are responsible for the control of the body and communication among its parts.
The document provides an overview of the nervous system, including:
- The central nervous system (CNS) which includes the brain and spinal cord.
- The peripheral nervous system (PNS) which includes nerves and ganglia outside the CNS.
- How neurons transmit signals via electrical and chemical processes.
- Key parts of the human brain like the cerebrum, cerebellum, and brain stem.
- Common neurological disorders like Alzheimer's, Parkinson's, depression and drug addiction.
The document provides an overview of the nervous system, including:
- The central nervous system (CNS) which includes the brain and spinal cord.
- The peripheral nervous system (PNS) which includes nerves and ganglia outside the CNS.
- How neurons transmit signals via electrical and chemical processes.
- Key parts of the human brain like the cerebrum, cerebellum, and brain stem.
- Common neurological disorders like Alzheimer's, Parkinson's, depression and drug addiction.
Endocrine system and Nervous system SEE science NepalAnjan Nepal
The nervous system is divided into the central nervous system (brain and spinal cord) and the peripheral nervous system (nerves outside the CNS). The brain is made up of the cerebrum, cerebellum and brain stem. The cerebrum controls higher functions like thought and memory. It is divided into four lobes. The cerebellum coordinates movement and balance. The brain stem connects the brain to the spinal cord and controls involuntary functions. The spinal cord carries signals between the brain and body. It gives rise to 31 pairs of spinal nerves. The peripheral nervous system includes 12 pairs of cranial nerves and spinal nerves that connect the CNS to organs and tissues. The autonomic nervous system controls involuntary functions through the
The document summarizes the development and structure of the spinal cord. It discusses how the spinal cord forms from neuroblasts in the alar and basal plates during embryonic development. It describes the location and functions of the spinal cord, including how it provides communication between the brain and body and contains spinal reflex centers. It also outlines the protection provided by bones, meninges, cerebrospinal fluid, and ligaments.
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The nervous system:part IV
1. The Nervous System/Part IV
Dr. Fawaz A. Mustafa
PhD in Medical Physiology and Pharmacology
Unlimited permission is granted free of charge to print or photocopy all pages of this
work for educational, not for profit use by university staff or students
2. Transmission of sensation to the
brain
• All the sensations go upward in the spinal cord or
they go through trigeminal nerve, then the nerve
fibres ascend to the thalamus, there is crossing of
fibres to the opposite side either in spinal cord or
brainstem
• In each hemisphere, there are sulci and gyri
• The brain has four lobes: frontal, parietal, temporal
and occipital
3.
4. Transmission of sensation to the
brain
• In the middle, there is a central sulcus. Any gyrux
posterior to it is called “postcentral gyrux”, and
any one anterior to it is called “precentral gyrux”
• Anything behind the central sulcux is concerned
with sensory, and in front of, it is concerned with
motor
• The parietal lobe is concerned with the
proprioception, the occipital with vision, temporal
with hearing and some tastes, frontal with motor
5. Transmission of sensation to the
brain
• The postcentral gyrux represents the body as
following:
1. The cerebral cortex of the postcentral gyrux
receives the sensations of the opposite side of the
body
2. The body, in this area, is represented upside down
3. Any part in the body is represented in the gyrux
according to the number of the receptors in that
part
6.
7. Transmission of sensation to the
brain
• The sensations should go to the postcentral gyrux
of the cerebral cortex because this region is the
final centre for:
a. Analysis
b. Sometimes, the sensation is stored or it discarded.
The storage is as memory
c. Localisation of the sensation
d. Production of synthetic sensation, such as
stereognosis or proprioception, which combine
many forms of sensations to produce body image.
8. Transmission of sensation to the
brain
The more complicated sensations, the more need for
well-developed cerebral cortex. But, the question is:
Do we need the cerebral cortex for all sensations?
9. Motor system
• It is concerned with movement
• Human beings can do very skilled movement
(writing, drawing, sewing) with their fingers as
compared with animals which cannot do skilled
movements
• These skilled movements are not occurring
spontaneously (from infancy). They need practice
and experience to learn skilled movements
10. Motor system
• To perform skilled movements, we need the help of
other movements. These other movements are
called “postural movements”
• The postural movement is changeable according to
the skilled movement
• Skilled movement is highly organised, while the
postural movement is not. So, each is
complementary to each other
11. Motor system
• Who is doing the movement? Or by what
we can produce movement?
12. Motor system
• In terms of movements, there are agonist and
antagonist muscle.
• Agonist is a group of muscle trying to produce the
movement
• Antagonist is a group of muscle which opposes the
movement
• In any movement, we should stimulate the agonist
and inhibit the antagonist.
13. Motor system
• Movement to be produced needs 3 points:
1. Movement is produced by a group of muscles, and
this includes stimulation of agonist and inhibition
of antagonist.
2. The postural movement. i.e. proper positioning of
a group of joints.
3. Coordination of movement between agonist and
antagonist. Without coordination, movement can
be too fast or too slow but correction produce the
exact wanted movement.
14. Motor system
• Moreover, to produce movement, 4 elements are
needed:
1. Conception and understanding the stimuli whether
it is external or internal (which is the information
stored in the memory area).
2. Planning for a movement
3. The stimulation of many muscles (either those of
body position, or those of joints or those of doing
movement)
15. Motor system
4. Proper watching of the movement. There is actual
movement and intended movement. Sometimes,
the actual movement is as the intended
movement, and other times it goes too far beyond
what it is intended. If the difference between them
is zero, this is proper movement. This is done by
continuous watching of movement. When
movement goes on, it sends impulses from joints,
muscle spindles,… etc. and these impulses goes
to the cerebellum
16. Motor system
• The movement is so complicated. Therefore, there
is need of centre by which we can do all these
elements
• This centre is present in the frontal lobe in the
precentral gyrux (or primary motor area) where the
body (and not the muscles) is represented.
17. Motor system
• The characteristics of this representation are:
1. The body is represented upside down. the most superior
region of the gyrux is related to foot and lower parts, while
the movement of the head are controlled by the inferior
region the precentral gyrux.
2. The movement of the right side of the body is controlled by
the left precentral gyrux, and that of the left side is
controlled by the right precentral gyrux
3. The area representation of precentral gyrux is related to
the skilled movement. The more skilled movement, the
more surface area in the precentral gyrux
18.
19. Motor system
• One of the area involved in the motor system is the
primary motor area. The cerebral cortex, regarding
the primary motor area, is considered as the top
level
• Its responsibility is the plan and the idea about
movement which are formulated or synthesised in
their regions: the primary motor area, premotor
area (in front of it) and motor association area,
which are the areas that take the information and
got an idea about movement (the plan for
movement)
20.
21. Motor system
• Other two structures of brain involved in motor
system are the basal ganglia and the lateral
hemisphere of the cerebellum
• For movement, there is a need of planning which is
done by the previously mentioned three structures
or areas
• After planning, execution occurs by orders sent
downward for movement to start. Execution (or
performing) the movement is done by a group of
muscles which are supplied by motor nerve fibres
22. Motor system
• Any skeletal muscle below the head is supplied by
motor axons of cells in the anterior horn of the
spinal cord, while any muscle in the head is
supplied by motor axons of cells in the nuclei of the
motor cranial nerves
• These motor axons are always excitatory to the
muscles, and through these axons, action potential
goes to the muscles causing sliding of actin and
myosin on each other (i.e. contraction)
23. Motor system
• The contraction of these muscles does not occur
haphazardly, but there is a control of these motor
nerve by orders from above (i.e. primary motor area
and brainstem)
• The lower level of spinal nerves are not working by
themselves but they work under the control of
higher centre called “upper motor neuron”
24. Motor system
• The lower motor neurons are from the cells of the
anterior horn of the spinal cord or cells of the motor
nuclei of the cranial nerves to the muscles
• The lower motor neurons are always excitatory to
the skeletal muscles under the control of the upper
motor neurons
• The upper motor neurons are of two types: direct
and indirect
• The direct is either corticospinal tract or
corticonuclear tract, both of which are called
“pyramidal tract”
25. Pyramidal tract
• The corticospinal tracts begin at the precentral
gyrus then come down through the pons and
midbrain and when they reach medulla oblongata,
and they cross to the opposite side forming
pyramids of the medulla, then they descend in the
cervical and the thoracic, lumbar and sacral giving
branches ending in the white matter in the lateral
side of the spinal cord, and some continue to end in
the anterior horn cells at each segments
26. Pyramidal tract
• The corticonuclear tracts also begin from the
cerebral cortex to the nuclei of the motor cranial
nerves. Also, crossing to the opposite side occurs
(i.e. the right hemisphere affects the left side, and
vice versa).
• The direct pyramidal corticospinal and
corticonuclear tract are responsible for activity or
movement of the distal muscles of the body
(muscles of hand, foot, .. etc.)
27. Extrapyramidal tracts
• Other tracts are responsible for postural movement by
indirect pathway called “extrapyramidal tracts”
• The origin of these tracts is usually from the brainstem, in
which there are many nuclei that are motor in origin giving
rise to axons which run downward in the form of group or
bundles ending in the median region of the spinal cord, and
they have different names.
• Some of them come from the reticular formation of pons
region and they are called “pontine reticulospinal tracts”
till the reach the median region of the white matter of the
spinal cord. This tract activates the proximal extensor group
of muscles (such as triceps in the upper limbs, and the
quadriceps in the lower limbs).
28. Extrapyramidal tracts
• The other tract is the “medullary reticulospinal
tract” (that originates from red nucleus) which
activates the proximal flexor muscles (such as the
biceps, branchials, … etc. in the upper limbs, and
the hamstring in the lower limbs).
• Another tract is called “reticulospinal tract” which
originates in the superior colliculus in the midbrain,
then it runs downward, and these are responsible
for certain movements (such as turning the head
towards the stimulus).
29. Motor system
• The cell body of the lower motor neuron is present
in the anterior horn. These tracts come from the
above to the spinal cord to influence the lower
motor neurons (anterior horn cells).
• The direct and indirect tracts influence the anterior
horn cells by another called “intermediate neuron”
which is a small neuron that transmits the action
potential to the anterior horn cells.
30. Motor system
• The direct tracts as well as the rubrospinal tract
descend in the white matter in the lateral side of the
spinal cord, while the indirect tract descends in the
white matter at the median region.
• The direct and indirect tracts, some are excitatory
and others are inhibitory. So, the anterior cells
receive many influences, excitatory and inhibitory.
• The summation of these descending tracts, if it is
excitatory, the lower motor neurons are excited, if it
is inhibitory, the lower motor neurons are inhibited.
The lower motor neurons are always excitatory to
the skeletal muscles.
31. Motor system and movement
• The tracts that descend in the lateral portion of the
spinal cord concerned with the skilled movement
affecting the distal muscles of the body, while those
of the median portion is concerned with postural
movement affecting the proximal truncal muscles
• The final element in movement is the muscles
• “Motor unit” may be defined as nerve cell body
giving axon whose branches go to many muscle
fibres. Each muscle consists of many motor units
32. Motor system and movement
• The basic unit of lower motor neuron is the motor
unit. The lower motor unit neuron extends from the
cell body to the muscle, while the upper motor unit
is the tracts above the muscles.
• To make a muscle to contract, excitation of the
muscle with action potential from the cell body is
needed, conducted through axons to the muscle
yielding sliding phenomenon of the actin and
myosin filament (i.e. muscle contraction)
33. Motor system and movement
• There are two types of motor units:
1. Phasic motor units: they are those capable of
producing rapid contraction. They are wide and
myelinated nerve fibres conducting rapid action
potential. Phasic motor units cause rapid
contraction and relaxation (such as in running and
jumping), so they fatigue easily and not last for
long time.
2. Tonic motor units: they are motor units in which
muscle contraction is slow and continuous, thus,
they produce slow movements (such as postural
movements). They don’t fatigue easily.
34. How movement is produced
• First of all, it must be planned in the cerebral cortex
of the precentral gyrus (in the primary motor area,
premotor area and supplementary motor area).
This is the higher centre. The precentral gyrus is
the place where the body is presented in motor
system, this is why the is formed here.
• The plan comes from the higher centre via the
upper motor neuron in tracts that are either direct
(for skilled movements) or indirect (for postural
movements)
35. How movement is produced
• The upper motor neurons control the lower ones.
The anterior horn cells of many levels of the spinal
cord are activated, not only one level. This is
because if we want to produce a movement, a
group of muscle should be activated to contract,
and other should be inhibited to relax.
• To eat, the plan comes from the higher centre and
is conducted through upper motor neurons which
end in the nuclei of the brainstem and not in the
spinal cord. Then, the lower motor neurons send
orders to the superficial muscles to do so and the
muscle of mastication to do so
36. How movement is produced
• Talking involves movement of the muscles of lips,
tongue, jaw, larynx and the respiratory muscles,
which all are supplied by nerve fibres from nerve
cell in the brainstem nuclei. The nuclei don’t work
by themselves by the are controlled by the higher
centre. The relation between the upper motor
neurons and lower motor neurons is that the upper
ones command the lower ones to do so and so,
and lower ones are always supervised or over
checked by the upper motor neurons.
37. How movement is produced
• Whenever there is no check from the higher centre,
dissociation results. Therefore, the movement is
always produced by interaction between upper and
lower motor neurons
• If a nerve is cut, there will be a defect in the muscle
and this may obstruct the movement. But, if there is
something wrong with the cerebral cortex (as in
cerebral infarction), the movement will be affected
despite the fact that there is nothing wrong with the
muscles. So, the upper motor neurons are
concerned with movement while the lower ones are
concerned with the muscles