This is the power point for professors associated with neurophysiology lectures. It can be used for medical, dental, nursing, paramedicals and many more associated with medicine.

1. Dr Subodh Yadav
Associate Professor
MBBS.MS.DMUD
Membrane Potentials & Synaptic
Transmission

2. Learning Objectives
At the end of this class, you should be able to understand:
 Define & Identify on a diagram of a neuron – dendrites , axon,
axon hillock ,soma & Synaptic cleft.
 Classification of neuron
 Classification of Neuroglia.
 Neuronal degeneration and regeneration

3. Structure

4. Neurons, neuroglia and organization of the
nervous system

5. Overview of the nervous system

6. Functions of the nervous system
 Sensory- detection of internal and external stimuli (sensory
neurons)
 Integrative- processing of sensory information (interneurons)
 Motor- response to integrated “decision” (motor neurons)

7. Organization of the nervous system

8. Structure and function of neurons
 Act through propagation of
action potentials
 Vary considerably in size
 Dendrites, cell body and axons
 May be myelinated
 Synapse with other neuron or
muscle cell; release
neurotransmitters

9. Neurotransmitter action
 About 100 neurotransmitters
known
 Amino acids, polypeptides,
gases
 Released into synaptic cleft,
bind to membrane of target
cell

10. Structural diversity in neurons
 Multipolar- many dendrites, one axon
 Most neurons in CNS
 Bipolar- one dendrite, one axon
 Sensory organs
 Unipolar- sensory
 Axon termini extend into CNS

14. Neuroglial cells
 Much smaller than neurons and more numerous
 Do not propagate action potentials
 Can replace themselves

15. Four types of neuroglia in CNS
 Oligodendrocytes
 Myelinating cells
 Astrocytes
 Blood-brain barrier (BBB)
 Microglia
 Phagocytes (from bone marrow)
 Ependymal cells
 Line ventricles of brain; produce cerebrospinal fluid
(CSF)

16. Neuroglia of the CNS

17. Neuroglia of the PNS
 Schwann cells
 Myelinating cells
 Help direct axon
regeneration
 Satellite cells
 Support, protection,
regulation of molecular
exchange

18. Why myelin?
 Increases speed of nerve
impulse transmission
 Myelinating cells leave gaps on
axons (nodes of Ranvier)
 Schwann cells can help
regenerate axons
 Demyelination can lead to loss
of function (MS)

21. Gray and white matter

25. 4.Depending upon Function

27. Classification of nerve

30. Ligand gated ion channel…..muscle cells

31. SALTATORY CONDUCTION
31

32. Synaptic transmission

33. Impulses in dendrites
EPSP & IPSP
EPSP-Excitatory post synaptic potential
IPSP-Inhibitory post synaptic potential

34. Events of Synaptic transmission

36. Repair and regeneration of neurons
 Neurons can grow new dendrites or axon termini
 Repair is limited to certain neurons in the PNS
 Growth factors promote formation of new neurons; limited to
specific regions of brain (hippocampus) in human adults
 Growth does occur in fetal and juvenile stages- what turns it
off?

38. Medically significant conditions
 Multiple sclerosis (demyelination)
 Epilepsy (uncontrolled electrical discharges)
 Tumors
 Neuropathies- affect specific nerves
 Infectious disease
 Wallerian degeneration

39. Clinical Considerations
 Lambert – Eaton syndrome – loss of voltage gated
Ca2+ channels,Treatment: Guanidine & calcium
gluconate.
 Cystic fibrosis – impaired Cl- ion channels – inherited
disease affects airways of lungs.
 Myasthenia gravis – autoimmune disease against nAch
in motor end plates.
 Botulism & Tetanus – affect SNARE proteins.

40. MCQ
 Which statement describes the membrane
potential at the peak of an action potential?
A) The membrane potential is slightly less positive than
the Na+ equilibrium potential.
B) The membrane potential is much more positive than
the Na+ equilibrium potential.
C) The membrane potential is slightly more positive than
the Na+ equilibrium potential
D) The membrane potential is the same as the Na+
equilibrium potential.
Key--A

41.  Which of the following neuronal processes
transmits an action potential?
a) Soma
b) Dendrite
c) Glia
d) Axon
Key-D

42.  Which of the following is the correct definition of a
cation?
A) A cation is a positively charged ion.
B) A cation is an ion that can have a positive or
negative charge.
C) A cation is a negatively charged ion.
D) A cation is an ion that cannot have a charge.
Key-A

43. Thank you