This is second part of Nervous system intended to explore just Nerve impulse transmission.

1. Human Nervous
System Part II
Nerve Impulse
Transmission
Dr. Aniket A. Shilwant
Assistant Professor
Dept. of Kriya Sharir
GJP-IASR

2. 22
Role of Synapse
 It is main function of – Synapse
 Nerve impulse transmission – Transmission of AP from one to another Neuron
 Synapses –
 Excitatory synapses – Transmit the impulses (excitatory function)
 Inhibitory synapses – Inhibit the transmission of impulses (inhibitory function)
or Inhibits, decreases the magnitude of excitatory impulses
Dr. Aniket A. Shilwant, GJP-IASR

3. 3
Terminologies
 EPSP
Excitatory Post Synaptic Potential
Excitatory function
 IPSP
Inhibitory Post Synaptic Potential
Inhibitory function
Dr. Aniket A. Shilwant, GJP-IASR

4. 4
Structures involved in Nerve Impulse Transmission
 Presynaptic membrane
 Synaptic cleft
 Postsynaptic membrane
 Presynaptic membrane -
 Axon terminal
 Mitochondria
 Synaptic Knob – Synaptic Vesicles – Neurotransmitters
 Postsynaptic membrane
 Receptor proteins
 Synaptic cleft
 Basal lamina
Dr. Aniket A. Shilwant, GJP-IASR

5. 5
Process involved in Nerve Impulse Transmission
Categorization of All Process involved in Nerve Impulse Transmission
 Process in Axon terminal of Presynaptic Neuron
 Process in Synaptic cleft
 Process in Axon / Dendron / Soma
of Post synaptic Neuron
Dr. Aniket A. Shilwant, GJP-IASR

6. Process in Axon
terminal of
Presynaptic Neuron
6
1
Arrival of Action
Potential at Axon
terminal
2
Opening of Voltage
gated channels
(Calcium channels)
3
Influx of Calcium ions
in Axon terminal
from ECF
4
Depolarization
5
Synaptic vesicles -
Burst
6
Release of
Neurotransmitters
Dr. Aniket A. Shilwant, GJP-IASR

7. 7
Process involved in Nerve Impulse Transmission
Process in Synaptic cleft
Passage of Neurotransmitters through Synaptic cleft
Role of Basal lamina -
Enzymes for reuptake and utilization of NT used and broken down
Dr. Aniket A. Shilwant, GJP-IASR

8. Process in receiver
terminal of
Postsynaptic Neuron
– Excitatory
Function
8
1
Formation of HR
complex
2
Opening of Ligand
gated channels
(Sodium channels) &
Sodium influx
3
Development of
Endplate / Receptor
Potential
4
Opening of Voltage
gated channels (Sodium
channels) & Sodium
influx
5
Development of
Action Potential
6
Spread of AP through
post synaptic neuron
Dr. Aniket A. Shilwant, GJP-IASR

9. Process in receiver
terminal of
Postsynaptic Neuron
– Inhibitory
Function
9
1
Formation of HR
complex
2A
Opening of Ligand
gated channels
(Potassium channels)
& Potassium eflux
2B
Opening of Ligand
gated channels
(Chloride channels) &
Chloride influx
3
More Negativity
within Neuron
4
Hyperpolarization
5
Inhibition of Spread
of AP in post synaptic
neuron
Dr. Aniket A. Shilwant, GJP-IASR A. Direct Inhibition

10. 10
Inhibition of Nerve Impulse Transmission
 Direct Inhibition
 Indirect Inhibition
 Negative Feedback Mechanism
 Feedforward Inhibition
 Reciprocal inhibition
Dr. Aniket A. Shilwant, GJP-IASR

11. 11
Inhibition of Nerve Impulse Transmission
B. Indirect Inhibition
 In spinal cord, Presynaptic inhibition - Axoaxonal synapses.
 Modulatory neuron – Presynaptic inhibitory neuron joins with regular
presynaptic neuron
 Normally, there is always EPSP at Postsynaptic terminal.
 This Modulatory neuron –
• Inhibits the presynaptic neuron
• Decreases intensity and magnitude of action potential in presynaptic neuron
 Thus reduction in calcium influx – ultimately insufficient quantity of NT released
by Presynaptic neuron.
Dr. Aniket A. Shilwant, GJP-IASR

12. 12
Inhibition of Nerve Impulse Transmission
C. Negative Feedback Mechanism
Renshaw cells of Spinal cord.
Dr. Aniket A. Shilwant, GJP-IASR

13. 13
NEURAL CIRCUITS
Dr. Aniket A. Shilwant, GJP-IASR

14. 14
Inhibition of Nerve Impulse Transmission
D. Feedforward Inhibition
 Occurs in Cerebellum
 Controls Neuronal activity in Cerebellum
 Series of stimulation of cells present in Grey
matter of Cerebellum.
 Inhibition of Purkinje cells by releasing
GABA
Dr. Aniket A. Shilwant, GJP-IASR

15. 15
Inhibition of Nerve Impulse Transmission
E. Reciprocal inhibition
 Inhibition of antagonistic muscles when a group of
muscles are activated is called reciprocal inhibition.
 It is because of reciprocal innervation.
Dr. Aniket A. Shilwant, GJP-IASR

16. 16
Significance of Synaptic Inhibition
 Synaptic inhibition in CNS limits number of impulses
 Enables precise, proper and appropriate action.
 Select exact number of impulses required.
 Omit or block the excess ones.
 Renshaw cells. Ex. Clostridium Tetany – Tetanus
 Purkinje cells. Ex. Gluten Ataxia
 Effect of poison destroys inhibitory response. Ex. Strychnine
 Nervous disorders Ex. Parkinsonism
Dr. Aniket A. Shilwant, GJP-IASR

17. Thank You All !!!
Dr. Aniket A. Shilwant
Assistant Professor
Department of Kriya Sharir
GJP-IASR
Email – ayuraniket18@gmail.com
http://ayugjac.edu.in/Staff_CV.aspx?dl=dn3Mja19480dn3Mja19
http://scholar.google.co.in/citations?user=636K2sMAAAAJ&hl=en
https://www.researchgate.net/profile/Aniket_Shilwant