Page 72 - Physiology and Pathophysiology MNU 2024-2025 نظرى

Clinical pharmacy 2024/2025 Level 2 Pharm D Physiology and Pathophysiology (MD303)
Conduction in Myelinated Axon Conduction in an Unmyelinated Axon
(Saltatory conduction).
 Depolarization jumps from one Node of  Cable spread of depolarization with
Ranvier to another since current is unable influx of Na  depolarizes the adjacent
+
to flow through myelin. region membrane  propagating the

 Conduction rate is rapid. AP.
 Conduction rate is slow: AP must be
produced at every fraction of
micrometer.
▪ Occurs in nerves that innervate skeletal ▪ Occurs in nerve fibers carrying less
muscle so that movements can be done important information, such as those

rapidly. regulating slow digestive processes

Multiple Sclerosis

 In patients with multiple sclerosis, neurons in the brain, spinal cord & optic nerve are demyelinated.

 The loss of myelin  slows down the conduction of APs  muscle weakness, numbness, fatigue,

difficulty with walking & loss of vision.

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