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Peripheral Nervous System
- The peripheral nervous system (PNS) consists of nerves that branch from the CNS (brain and spinal cord)
- Two major sets of nerves: cranial and spinal
- PNS can be subdivided into somatic (control) and autonomic (no control) nervous system
- Somatic nervous system consists of cranial nerves and spinal nerves that connect to the skin and skeletal system
- Autonomic nervous system connect to visceral organs (heart, stomach, glands...)
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Cranial nerves
- Olfactory nerve (I): sense of smell
- Optic nerve (II): sense of vision
- Oculomotor (III): movement of eye muscles
- Trochlear (IV): movemetn of eye muscles
- Trigeminal (V):
- Sensory to face at the anterior scalp and the lacrimal glands, upper teeth, upper lip, behind the ear, and the lower lip
- Motor to muscles for mastication and the floor of the mouth
- Abducens (IV): motor fibers to the eye muscle
- Facial nerve (V):
- Sensory to taste
- Motor to muscles of facial expression
- Vestibulocochlear nerve(VI): sensory for balance and hearing
- Glossopharaneal (IX):
- Sensory to tongue and pharynx
- Motor to pharynx and swallowing
- Vagus nerve (X): sensory and motor to larynx, heart, and viscera
- Accessory nerve(XI): motor to neck and upper muscles
- Hypoglossal nerve(XII): motor fibers to tongue during chewing, speaking, and swallowing
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Spinal nerves
- 31 pares of cranial nerves originate from the spinal cord
- Mixed nerves that allow communication between the spinal cord and various parts of the body
- 5 groups of nerves: cervical (8), thoracic (12), lumbar (5), sacral (5), coccygeal (1)
- Spinal nerves form complex network called plexus
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Cervical plexuses [NECK]
- Lie deep within the neck
- Supply muscles and skin of the neck
- Includes the phrenic [central respiration] nerve which innervates the diagram
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Brachial plexuses [ARM]
- Located deep within the shoulder
- Supply the skin and muscles of the arm, forearm, and the hand
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Lumbosacral plexuses [LEG]
- Extend from the lumbar region of the back into the pelvic cavity
- Supply the muscle and skin of the lower abdominal wall external genitalia, thighs, legs, and feet
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