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.
The detail description about peripheral nervous system, neuron, its covering, types of neuron, synapses, spinal nerves, plexus, and more about cranial nerves at last not the least about somatic and autonomic nervous system. you may also find the information about types of peripheral nervous system in detail.
The detail description about peripheral nervous system, neuron, its covering, types of neuron, synapses, spinal nerves, plexus, and more about cranial nerves at last not the least about somatic and autonomic nervous system. you may also find the information about types of peripheral nervous system in detail.
about nerve fibers
It is the structural and the functional unit of nervous system.
The human nervous system contains approximate 1012 neurons.
A nerve fiber is a thread like extension of a nerve cell and consists of an axon and myelin sheath (if present) in the nervous system.
In peripheral nervous system it is formed by
schwann’s cell. While in case of central nervous system it is formed by oligodendroglia.
The places ,where myelin sheath is absent are called node of ranvier(2-3µm) and these are present once about 1-3 mm distance along the myelin sheath.
IT PREVENTS LEAKAGE OF IONS BY 5000 FOLDS.
IT INCREASES VELOCITY OF CONDUCTION BY 5-50 FOLDS DUE TO
SALTATORY CONDUCTION i.e. ABOUT 100 m/s IN CASE OF
MYELINATED NERVE FIBERS WHILE IN NONMYELINATED
IT IS ABOUT 0.25 m/s.
SALTATORY CONDUCTION CONSERVES ENERGY BECAUSE ONLY NODES OF RANVIER GET DEPOLARISED.
These are α type motor nerve fibers.
The neurotransmitter released at the neuron endings is acetylcholine(Ach).
It always leads to muscles excitation . Inhibition takes place centrally due to participation of interneurons.
they innervate smooth muscles , cardiac muscles and glands.
Their main work is to maintain homeostasis with the help of autonomic nervous system.
they can lead to either excitation or inhibition of effector organs
Erlanger and Grasser studied the action potential of mixed nerve trunk by means of cathode ray oscilloscope and they obtained the compounded spike. So they divided nerve fibers into 3 groups. They observed that the main cause of difference in nerve fibers is diameter
AS Diameter increases
Velocity of conduction increases.
Magnitude of electrical response increases.
Threshold of excitation decreases.
Duration of response decreases.
Refractory period decreases.
about nerve fibers
It is the structural and the functional unit of nervous system.
The human nervous system contains approximate 1012 neurons.
A nerve fiber is a thread like extension of a nerve cell and consists of an axon and myelin sheath (if present) in the nervous system.
In peripheral nervous system it is formed by
schwann’s cell. While in case of central nervous system it is formed by oligodendroglia.
The places ,where myelin sheath is absent are called node of ranvier(2-3µm) and these are present once about 1-3 mm distance along the myelin sheath.
IT PREVENTS LEAKAGE OF IONS BY 5000 FOLDS.
IT INCREASES VELOCITY OF CONDUCTION BY 5-50 FOLDS DUE TO
SALTATORY CONDUCTION i.e. ABOUT 100 m/s IN CASE OF
MYELINATED NERVE FIBERS WHILE IN NONMYELINATED
IT IS ABOUT 0.25 m/s.
SALTATORY CONDUCTION CONSERVES ENERGY BECAUSE ONLY NODES OF RANVIER GET DEPOLARISED.
These are α type motor nerve fibers.
The neurotransmitter released at the neuron endings is acetylcholine(Ach).
It always leads to muscles excitation . Inhibition takes place centrally due to participation of interneurons.
they innervate smooth muscles , cardiac muscles and glands.
Their main work is to maintain homeostasis with the help of autonomic nervous system.
they can lead to either excitation or inhibition of effector organs
Erlanger and Grasser studied the action potential of mixed nerve trunk by means of cathode ray oscilloscope and they obtained the compounded spike. So they divided nerve fibers into 3 groups. They observed that the main cause of difference in nerve fibers is diameter
AS Diameter increases
Velocity of conduction increases.
Magnitude of electrical response increases.
Threshold of excitation decreases.
Duration of response decreases.
Refractory period decreases.
Nervous System -Autonomic Nervous System-Neurons -Ganglia - Nerves Copy.Home
The nervous system is the body's communication network, coordinating and regulating all bodily functions. Comprising the central nervous system (CNS) and peripheral nervous system (PNS), it consists of neurons, specialized cells transmitting electrical and chemical signals. The CNS, consisting of the brain and spinal cord, interprets and processes information. The PNS extends from the CNS, transmitting signals between the brain, spinal cord, and the rest of the body. Sensory neurons detect stimuli, while motor neurons control muscle movement. This intricate system enables sensory perception, voluntary and involuntary actions, and regulates bodily processes, ensuring homeostasis and facilitating responses to the environment.
Nervous System -Autonomic Nervous System-Neurons -Ganglia - Nerves Copy.Home
The nervous system is the body's communication network, coordinating and regulating all bodily functions. Comprising the central nervous system (CNS) and peripheral nervous system (PNS), it consists of neurons, specialized cells transmitting electrical and chemical signals. The CNS, consisting of the brain and spinal cord, interprets and processes information. The PNS extends from the CNS, transmitting signals between the brain, spinal cord, and the rest of the body. Sensory neurons detect stimuli, while motor neurons control muscle movement. This intricate system enables sensory perception, voluntary and involuntary actions, and regulates bodily processes, ensuring homeostasis and facilitating responses to the environment.
Coordinates voluntary and involuntary actions of the body and transmits signals between different parts of the body.
Together with endocrine system controls and integrates activities of the body.
Nervous system allows us to perceive, understand, and respond to our environment.
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
New Drug Discovery and Development .....NEHA GUPTA
The "New Drug Discovery and Development" process involves the identification, design, testing, and manufacturing of novel pharmaceutical compounds with the aim of introducing new and improved treatments for various medical conditions. This comprehensive endeavor encompasses various stages, including target identification, preclinical studies, clinical trials, regulatory approval, and post-market surveillance. It involves multidisciplinary collaboration among scientists, researchers, clinicians, regulatory experts, and pharmaceutical companies to bring innovative therapies to market and address unmet medical needs.
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
2. Outline
Introduction to the structure/function of central
nervous system (CNS)
Protection of CNS
Introduction to peripheral nervous system
(covered in more detail later)
Microanatomy: neurons
2
3. Divisions of the Nervous
System
http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/8679.jpg
Enteric nervous system
3
4. Divisions of the Nervous
System
http://faculty.washington.edu/chudler/nsdivide.html
4
5. CNS: Spinal cord
5
Functions
1. Conducts afferent
stimuli from
sensory receptors
to the brain
2. Conducts efferent
stimuli from brain
to
effectors/muscles
3. Site of reflex
integration and
houses certain
central pattern
6. CNS: Spinal cord input/output
Figure 4-8, B&L
6
Afferent fibre
Efferent fibre
*
* Part of the peripheral nervous system
*
*
*
*
7. CNS: Spinal cord tracts
7
Silverthorn Figure 9-7
Tract: collection of axons that ascend/descend
spinal cord with a specific function
1. dorsal columns: ascending tracts that
transmits tactile and proprioceptive info
2. spinothalamic tract: ascending tract that
transmits info about pain, temp. and itch
3. lateral corticospinal tract: descending tract
that carries motor information to skeletal
1
2
3
8. Divisions of the Nervous
System
http://faculty.washington.edu/chudler/nsdivide.html
8
9. 9
CNS: Brain, three basic units
Illustrative guide to the
basic units of the brain:
Forebrain/midbrain/
hindbrain
10. CNS: Brain, five regions
10
http://www.ruf.rice.edu/~lngbrain/cglidden/middlelabnoline!!yes2use2.jpg
Regions grouped and named as they develop
in the embryo
Figure 10-6, B&B
11. Forebrain part 1:
Telencephalon11
Includes all of the cerebral cortex and the
internal nuclei such as the basal ganglia,
hippocampus, the olfactory bulb and the
amygdala
http://www.3icreative.com/wp-content/uploads/2011/03/telencephalon-limbic-
system-300x251.jpg
12. Telencephalon: Cerebral Cortex
12
Outermost layer of the
cerebrum
Composed of 2-4mm of
gray matter
Up to 6 horizontal
layers with unique
neuronal projections
and functions
Figure 17-6 Kandel
14. Cerebral Cortex: Broadman’s
Areas
Organization based on
physiological function
Important areas we will visit
later:
Area 4 = primary motor
cortex
Area 3,1,2 = primary
somatosensory cortex
Area 17 = primary visual
cortex
Area 41, 42 = primary
auditory cortex
14
15. Telencephalon: Basal Ganglia
15
Functions
1. Motor control;
connections with motor
cortex and thalamus
2. Regulate initiation and
termination of
movements
3. Some role in attention,
memory and planning
16. Telencephalon: Amygdala &
Hippocampus16
Amygdala functions
1. Part of the limbic system
2. Associated with pleasure, fear,
addiction
3. Important in forming and storing
memories of emotional events
Hippocampus functions
1. Part of the limbic system
2. Important in formation of
memories, including spatial and
navigation memories
3. Damage to hippocampus can
result in anterograde amnesia
17. includes the thalamus and
hypothalamus
Telencephalon + diencephalon =
forebrain
Forebrain part 2: Diencephalon
17
Thalamus functions
1. Main integrating centre for
sensory information
2. Receives input from basal
ganglia and cerebellum
Hypothalamus functions
1. Main control centre for the
autonomic nervous system
2. Close association with pituitary
gland, important functions in the
endocrine system (hormone
release)
3. Contains nuclei important in
regulation of circadian clock,
hunger, thirst, heart rate, and
18. Two divisions:
a) tectum
superior colliculi
contain nuclei for visual
reflexes
inferior colliculi
contain nuclei for auditory
reflexes
b) tegmentum
substantia nigra
Release dopamine to basal
ganglia
red nucleus
Connections with cerebellum
for coordination of movement
Midbrain: Mesencephalon
18
19. Hinbrain: Myelencephalon
Two divisions:
a) myelencephalon
medulla oblongata
Contains ascending
and descending
sensory and motor
tracts connecting the
cerebrum to the spinal
cord
Most spinal cord tracts
cross over in the
pyramids
Contains nuclei that
regulate breathing,
blood pressure,
vomiting
19
20. Hinbrain: Metencephalon
b) metencephalon
pons
Contains pneumotaxic centre
which fine tunes breathing rate
Relays information between
cerebellum and cerebrum
cerebellum
Feedback center for execution
of motor movements
Controls posture and balance
reticular formation
Nuclei diffusely located through
the brainstem*
Regulates wakefulness and
muscle tone
20
*the term “brainstem” refers to the medulla oblongata, pons, and the midbrain
21. Divisions of the Nervous
System
http://faculty.washington.edu/chudler/nsdivide.html
21
22. CNS Protection
Against physical
damage
Against chemical
damage
Both
Skull/vertebrae
-hard external
protection
Blood brain barrier
- Tight junctions
form physical
barrier across
capillaries
Cerebrospinal
fluid
-Shock absorption
-Stable ionic
composition
Meninges
-Pia mater
(innermost layer)
-Arachnoid mater
-Dura mater
22
23. Protection: Blood Brain Barrier
23
CNS blood vessels prevent
paracellular diffusion of
macromolecules and ions
Capillary endothelial cells in the
brain are connected by tight
junctions to form a physical
barrier, with contribution from
astrocytes, pericytes & neurons
Specialized transporters required
for movement of most molecules
Small or lipophilic molecules and
gases can diffuse more easily
Caffeine, nicotine, heroin, CO2
24. Protection: Blood Brain Barrier
24
Only a few, small regions of the brain
are without a blood brain barrier
Creates problems for delivering
therapeutic drugs to the brain
Methods for drug targeting include:
Manufacturing low molecular
weight drugs
Tagging the drug with ligand to
assist in receptor mediated
transcellular transport
Injecting drug directly into brain
matter
25. Protection: Cerebrospinal Fluid
25
Fluid synthesized by the
choroid plexuses in each of
the four ventricles
Fills ventricles and
subarachnoid space
Less protein than
plasma with similar
electrolyte composition
(but more Cl-, less Ca2+
and K+)
Acts as a shock absorber
during impact
Removes waste, regulates
pH and maintains ionic
homeostasis of neuronal
microenvironment
27. Peripheral Nervous System
27
Autonomic Somatic
Parasympathet
ic
Sympathetic Sensory Motor
Rest and
digest
Flight or fight Afferent
neurons
carrying
information from
Efferent neurons
carrying
information from
the CNS to
all parts of nervous system outside the dura mater
includes sensory receptors, peripheral portions of
spinal and cranial nerves (including those of the
ANS), and sensory ganglia
sensory ganglia are aggregates of nerve cells located
outside the CNS
28. Microanatomy: Neurons and Glial
cells28
Neurons
Convey electrical signals within
CNS and PNS
Glial cells
regulate neuron environment
& form the myelin sheath
around neurons
a) Astrocytes: regulate
neuron environment
b) Oligodendrocytes: form
myelin sheath in CNS
c) Schwann cells: form myelin
sheath in PNS
d) Ependymal cells: line the
ventricles, synthesize CSF
e) Microglia: monocytes of the
brain
32. Objectives
After this lecture you should be able to:
List the types of neurons (afferent, efferent, sensory,
motor) contained in: dorsal root and ventral root
ganglion, ascending and descending tracts of the spinal
cord
List a major function of: frontal, parietal, temporal and
occipital lobes, reticular formation, medulla, pons,
midbrain, cerebellum, thalamus, hypothalamus, basal
ganglia, limbic system
Describe the modes of protection of the CNS
List the functions of various neurons and their respective
neuroglial cells
32
33. 33
1. The __________________ is the main control centre
for regulating functions of the autonomic nervous
system, secretes a variety of hormones, and contains
nuclei important for regulation of hunger and
temperature regulation.
2. What kind of protection is offered by the cerebrospinal
fluid?
3. ____________________ are referred to as the
monocytes of the brain and become phagocytic cells
when activated in order to removed debris.
Test your knowledge