Page 58 - Physiology and Pathophysiology MNU 2024-2025 نظرى

Clinical pharmacy 2024/2025 Level 2 Pharm D Physiology and Pathophysiology (MD303)
B) Motor nerve tracts (efferent)

Neurons which transmit nerve impulses away from the brain are motor (efferent or descending)
neurons.

Motor neuron stimulation results in:

1. Contraction of skeletal (striated, voluntary muscle).

2. Contraction of smooth (involuntary) muscle, cardiac muscle and the secretion by glands

controlled by nerves of the autonomic nervous system.

Spinal reflexes (Spinal arch reflexes)

Consist of three elements: Sensory neurons - Connector neurons in the spinal cord -Lower motor

neurons.

✓ An immediate motor response to a sensory stimulus.

✓ Reflex action takes place very quickly, in fact, the motor response may have
Character
occurred simultaneously with the perception of the pain in the cerebrum.
of reflex
✓ Reflexes of this type are invariably protective, but they can on occasion be
action
inhibited.

 Ex: if it is a precious plate that is very hot when lifted every effort will made to

overcome the pain to prevent dropping

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