2. The Rawalpindi Medical University
Dr. Shmyla Hamid
Associate Professor Physiology
CNS MODULE
PHYSIOLOGY LGIS
ORGANIZATION OF THE NERVOUS SYSTEM
&
MECHANISM OF SYNAPTIC TRANSMISSION
Date:05-06-2023
2
3. The Rawalpindi Medical University
Table of contents
3
Sr # Content Slide #
1 Motto, Vision 4
2 Professor Umar Model of Integrated Lecture 5
3 Bloom’s Taxonomy (Domains of learning) 6
4 Diagrammatic representation of Blooms taxonomy 7
5 Learning Objectives 8
6 Horizontal Integration 12, 13 ,14, 28 , 39, 40
7 Core Concept 9,10 & 14 to 24,27,29 to 38, 41, 42
8 Vertical Integration 25, 49
9 Biomedical Ethics (Lesson of the day) 51
10 Suggested research article 50
11 Brainstorming (MCQs relevant with the lecture) 43 to 48
12 Promoting IT and Research culture (Digital library) 52
13 References of this lecture 53
4. The Rawalpindi Medical University
Motto Vision; The Dream/Tomorrow
• To impart evidence based research oriented
medical education
• To provide best possible patient care
• To inculcate the values of mutual respect
and ethical practice of medicine
4
5. The Rawalpindi Medical University
5
ProfessorUmarModel of Integrated Lecture
60%
CORE SUBJECT
20%
HORIZONTAL
INTEGRATION
anatomy
biochemistry
8%
VERTICAL
INTEGRATION
Pathology
pharmacology
7%
VERTICAL
INTEGRATION
Clinical
integration
5%
VERTICAL
INTEGRATION
Research,
professionalism
Ethics
Digital library
6. The Rawalpindi Medical University
BLOOM'S TAXONOMY : DOMAINS OF LEARNING
Sr. # Domain of learning Abbreviation Levels of the
domain
Meaning
1 cognition C C1 Recall / Remembering
2 C2 Understanding
3 C3 Applying / Problem solving
4 Psychomotor P P1 Imitation / copying
5 P2 Manipulation / Follows instructions
6 P3 Precision / Can perform accurately
7 Attitude A A1 Receiving / Learning
8 A2 Respond / Starts responding to the learned
attitude
9 A3 Valuing / starts behaving according to the
learned attitude
8. The Rawalpindi Medical University
LEARNING OBJECTIVES
8
Sr. # Learning Objective Domain of Learning
1 To Illustrate the general design of the nervous system C3
2 To Describe the physiologic anatomy of the synapse C2
3 To Give a brief account of role of synapses in processing
information
C1
4 To Enlist the various types of synapses C1
5 To differentiate the various types of synapses C4
6 To Explain the mechanism of synaptic transmission C2
12. The Rawalpindi Medical University
Central Nervous System Neuron:
The Basic Functional Unit
•more than 100 billion neurons
• a typical neuron of a type found in the brain
motor cortex
• Incoming signals
• output signal
• the signal normally passes only in the
forward direction
HORIZONTAL INTEGRATION
PHYSIOLOGIC ANATOMY
Horizontal
Integration
12
13. The Rawalpindi Medical University
HORIZONTAL INTEGRATION
PHYSIOLOGIC ANATOMY
Horizontal
Integration
13
14. The Rawalpindi Medical University
HORIZONTAL INTEGRATION
PHYSIOLOGIC ANATOMY
Horizontal
Integration
14
15. The Rawalpindi Medical University
A-Sensory Part of the Nervous System—Sensory Receptors
Most activities of the nervous system are initiated by
sensory experience exciting sensory receptors visual
receptors, auditory receptors, tactile receptors, or other
kinds of receptors
Somatic portion of the sensory system, transmits sensory
information( surface & deep)--- receptors– pns--enters the
CNS and is conducted immediately to multiple sensory areas in
1. The spinal cord at all levels;
2. The reticular substance of medulla, pons, mesencephalon
of the brain;
3. The cerebellum;
4. The thalamus;
5. Areas of the cerebral cortex.
CORE
CONCEPTS
15
16. The Rawalpindi Medical University
B-Motor Part of the Nervous System— Effectors
Motor functions of the nervous system
1. Contraction of skeletal muscles throughout the body,
2. Contraction of smooth muscle in the internal organs, and
3. Secretion of active chemical substances by both exocrine and endocrine glands in
many parts of the body.
CORE
CONCEPTS
The muscles and glands are called effectors
because they are the actual anatomical
structures that perform the functions dictated
by the nerve signals.
16
17. The Rawalpindi Medical University
The skeletal muscles can be controlled
from many levels of the central nervous
System, including
1. The spinal cord;
2. The reticular substance of the medulla,
pons, and mesencephalon;
3. The basal ganglia;
4. The cerebellum; and
5. The motor cortex.
CORE
CONCEPTS
17
19. The Rawalpindi Medical University
C- Processing of Information— “Integrative” Function of
the Nervous System
most important function--- to process incoming information appropriate mental
and motor responses will occur.
More than 99 per cent of all sensory information is discarded by the brain as irrelevant and
unimportant. But, when important sensory information excites the mind, it is immediately
channeled into proper integrative and motor regions of the brain to cause desired responses.
the integrative function of the nervous system--- channeling and processing of information
CORE
CONCEPTS
19
20. The Rawalpindi Medical University
Role of Synapses in Processing Information
The synapse : is the junction point from one neuron to the next.
synapses determine the directions that the nervous signals will spread through the nervous
system.
Synaptic transmission is controlled by facilitatory and inhibitory signals from other areas in
the nervous system.
The synapses perform a selective action:
blocking weak signals
allowing strong signals to pass
selecting and amplifying certain weak signals
channeling these signals in many directions rather than only one direction.
Memory-- is a function of the synapses (facilitation)
CORE
CONCEPTS
20
21. The Rawalpindi Medical University
Major Levels of Central Nervous System Function
inherited special functional capabilities
From this heritage, three major levels of the central nervous system have
specific functional characteristics:
1. The spinal cord level,
2. The lower brain or subcortical level, and
3. The higher brain or cortical level.
CORE
CONCEPTS
21
22. The Rawalpindi Medical University
1. Spinal Cord Level
Even after the spinal cord has been cut in the high neck region, many highly organized
spinal cord functions still occur.
neuronal circuits in the cord can cause
1. Walking movements,
2. Reflexes that withdraw portions of the body from painful objects,
3. Reflexes that stiffen the legs to support the body against gravity, and
4. Reflexes that control local blood vessels, gastrointestinal movements, or urinary
excretion.
CORE
CONCEPTS
22
23. The Rawalpindi Medical University
2. Lower Brain or Subcortical Level
• Controls subconscious activities of the body
• in the medulla, pons, mesencephalon, hypothalamus, thalamus, cerebellum, and basal
ganglia
• medulla and pons subconscious control of arterial pressure and respiration
• older portions of the cerebellum and the reticular substance of the medulla, pons, and
mesencephalon Control of equilibrium.
• medulla, pons, mesencephalon, amygdala, and hypothalamus Feeding reflexes.
• Hypothalamus emotional patterns, can still occur after destruction of much of the
cerebral cortex.
CORE
CONCEPTS
23
24. The Rawalpindi Medical University
3. Higher Brain or Cortical Level
• cerebral cortex storehouse.
• The cortex never functions alone but always in association with lower centers of the
nervous system.
• The vast storehouse of cortical information usually converts these functions to
determinative and precise operations.
• the cerebral cortex is essential for most of our thought processes, but it cannot function by
itself.
• Without the cerebral cortex, the functions of the lower brain centers are often imprecise.
• In fact, it is the lower brain centers, not the cortex, that initiate wakefulness in the cerebral
cortex, thus opening its bank of memories to the thinking machinery of the brain.
CORE
CONCEPTS
24
27. The Rawalpindi Medical University
Central Nervous System Synapses
nerve action potentials--- “nerve impulses”
(1) may be blocked in its transmission from one neuron to the next,
(2) may be changed from a single impulse into repetitive impulses, or
(3) may be integrated with impulses from other neurons to cause highly intricate
patterns of impulses in successive neurons.
All these functions can be classified as synaptic functions of neurons.
CORE
CONCEPTS
27
28. The Rawalpindi Medical University
Physiologic Anatomy of the Synapse
Horizontal
Integration
28
29. The Rawalpindi Medical University
Types of Synapses—Chemical and Electrical
CORE
CONCEPTS
29
30. The Rawalpindi Medical University
Types of Synapses—Chemical and Electrical
chemical synapses –
mainly signal transmission in CNS
Almost all of the synapses in the CNS
Presynaptic neuron: the first neuron secretes at its nerve
ending a chemical substance called a neurotransmitter-- this
transmitter in turn acts on receptor proteins in the membrane
of the next neuron—postsynaptic neuron. (excites, inhibits, or
modifies its sensitivity)
“One-Way” Conduction at chemical synapses
40 important transmitter substances
acetylcholine, norepinephrine, epinephrine,histamine,
gamma-aminobutyric acid(GABA), glycine, serotonin, and
glutamate.
CORE
CONCEPTS
30
31. The Rawalpindi Medical University
Electrical synapses, are characterized by direct open
fluid channels that conduct electricity from one cell to
the next.
Most of these consist of small protein tubular structures
called gap junctions that allow free movement of ions
from the interior of one cell to the interior of the next.
Very few in the CNS but are the predominant type in the
periphery of the body (i.e. cardiac muscle and smooth
muscle)
CORE
CONCEPTS
31
34. The Rawalpindi Medical University
presynaptic membrane contains large numbers of voltage-gated calcium channels.
The quantity of transmitter substance that is then released from the terminal into the
synaptic cleft is directly related to the number of calcium ions that enter.
2000 to 10,000 molecules of acetylcholine are present in each vesicle.
CORE
CONCEPTS
34
39. The Rawalpindi Medical University
“Second messenger” system by which a transmitter substance from an initial neuron can
activate a second neuron by first releasing a “G-protein” into the second neuron’s cytoplasm.
HORIZONTAL INTEGRATION
BIOCHEMISTRY
Horizontal
Integration
39
40. The Rawalpindi Medical University
• Second Messenger Systems- the alpha
component of the G protein performs one
of four functions:
a. Opening specific ion channels
through the post-synaptic
membrane
b. Activation of cAMP or cGMP
c. Activation of one or more
cellular enzymes
d. Activation of gene transcription
HORIZONTAL INTEGRATION
BIOCHEMISTRY
Horizontal
Integration
40
41. The Rawalpindi Medical University
• Excitatory Receptors in the Postsynaptic Membrane
a. In excitation: the opening of Na channels to allow
large numbers of + electrical charges to flow to the
interior. This raises the membrane potential toward
threshold (most widely used method of excitation)
b. In excitation: depressed conduction through chloride
or potassium channels or both; decreases the diffusion
of Cl to the inside or K to the outside which makes the
membrane potential more positive
c. Metabolic changes to excite cell activity, increase
excitatory receptors or decrease inhibitory receptors
CORE
CONCEPTS
41
42. The Rawalpindi Medical University
• Inhibitory Receptors in the Postsynaptic Membrane
a. Opening of chloride channels allowing the rapid influx
of ions which causes the membrane potential to become
more negative, and therefore inhibitory
b. Increase in conductance of potassium ions out of the
neuron allowing positive ions to diffuse to the outside
causing increased negativitiy, and therefore inhibitory
c. Activation of receptor enzymes that inhibit metabolic
functions or increase the number of inhibitory receptors
or decrease the number of excitatory receptors
CORE
CONCEPTS
42
43. The Rawalpindi Medical University
1. Following is a characteristic feature of electrical synapse :
a. Unidirectional transmission
b. Bidirectional transmission
c. Neurotransmitter receptors
d. Neurotransmitter vesicles
e. Voltage gated calcium channels
MCQ # 1
Brain
Storming
43
44. The Rawalpindi Medical University
1. Following is a characteristic feature of electrical synapse :
a. Unidirectional transmission
b. Bidirectional transmission*
c. Neurotransmitter receptors
d. Neurotransmitter vesicles
e. Voltage gated calcium channels
KEY # 1
Brain
Storming
44
45. The Rawalpindi Medical University
2. Neurotransmitter receptors that act through second
messenger systems are called:
a. Ionotropic receptors
b. Metabotropic receptors
c. Muscarinic receptors
d. Alpha receptors
e. Nicotinic receptors
MCQ # 2
Brain
Storming
45
46. The Rawalpindi Medical University
2. Neurotransmitter receptors that act through second
messenger systems are called:
a. Ionotropic receptors
b. Metabotropic receptors*
c. Muscarinic receptors
d. Alpha receptors
e. Nicotinic receptors
KEY # 2
Brain
Storming
46
47. The Rawalpindi Medical University
4. The inhibitory synapses mainly:
a. Open chloride channels
b. Close chloride channels
c. Open sodium channels
d. Allow potassium influx
e. Allow bicarbonate efflux
MCQ # 3
Brain
Storming
47
48. The Rawalpindi Medical University
4. The inhibitory synapses mainly:
a. Open chloride channels*
b. Close chloride channels
c. Open sodium channels
d. Allow potassium influx
e. Allow bicarbonate efflux
KEY # 3
Brain
Storming
48
49. The Rawalpindi Medical University
49
VERTICAL INTEGRATION
Seizures and Epilepsy
• Seizures are temporary
disruptions of brain
function caused by
uncontrolled excessive
neuronal activity.
• Cerebral epileptic seizures
occur because of increased
excitability of some or all
of the cerebral neurons.
VERTICAL
INTEGRATION
50. The Rawalpindi Medical University
SUGGESTED RESEARCH ARTICLE
PROMOTING RESEARCH CULTURE
50
WEB LINK: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9313035/
51. The Rawalpindi Medical University
• It is a code of conduct for the members of the medical
profession in order to render the best possible services to
humanity and maintain the honor and dignity of the profession.
BIOMEDICAL ETHICS
Lesson of the day
51
Understanding
biomedical
ethics
52. The Rawalpindi Medical University
• Steps to Access HEC Digital Library
1. Go to the website of HEC National Digital Library.
2. On Home Page, click on the INSTITUTES.
3. A page will appear showing the universities from Public and Private Sector
and other Institutes which have access to HEC National Digital Library HNDL.
4. Select your desired Institute.
5. A page will appear showing the resources of the institution
6. Journals and Researches will appear
7. You can find a Journal by clicking on JOURNALS AND DATABASE and enter a
keyword to search for your desired journal.
How To Access Digital Library
52
PROMOTING IT AND RESEARCH CULTURE
53. The Rawalpindi Medical University
REFERENCES
1. Guyton and Hall text book of medical physiology, 14th edition
2. Human Physiology by Lauralee Sherwood, 9th edition
3. Ganong’s Review of Medical Physiology, 26th Edition
4. Berne and Levy Physiology-7th Edition
5. Costanzo Physiology by Linda S. Costanzo, 7th edition
6. Human Physiology: An Integrated Approach, by Silverthorn-8th edition
7. Best & Taylors Physiological Basis of Medical Practice-13th Edition 53
