ANHB3324 Lecture Notes - Lecture 4: Autonomic Nervous System, Dorsal Root Ganglion, Cranial Nerves
3 Jun 2018
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LECTURE FOUR: Functional Components of Cranial Nerves
Spinal Nerve Components:
• Somatic → skin, muscles, mucosa, connective tissue
• Visceral → glands, heart, lungs, gut, blood vessels
General Spinal Nerve Components:
• General somatic sensory → from the body → GSS
• General somatic motor → to the body → GSM
• General visceral sensory → from the viscera → GVS
• General visceral motor → to the viscera → GVM → ANS output
(parasympathetic/sympathetic)
Cranial Nerve Components:
• General → relating to whole body → e.g. skin, pain, touch
• Special → unique to cranial nerves → e.g. smell, sight, taste, hearing,
balance
Spinal Nerve Development:
• Neural tube formed ~ 4 weeks
• Ectodermal origin
• Dorsal half → sensory
• Ventral half → motor
• Underneath → notochord
• Sensory half live in dorsal root ganglion outside tube → derived from
neural crest cells
• Motor half have cell bodies in grey matter of spinal cord → ventral horn
Cranial Nerve Development:
• Cranial nerves come off brain stem
• Dorsal end breaks apart → top part opens up in brain
• Sensory goes to periphery as you move towards brainstem
• Motor remains in middle of brainstem
• Symmetric left and right
• Left with a sleeve over top → roof of 4th ventricle
Cranial Nerve Nuclei:
• Nuclei → cluster of neuronal cell bodies
embedded in brain tissues
• Location in the brain stem of collections
of nerve cells
• Sensory → where first order input
nerves relay
• Motor → where lower motor neurons
lie
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