ANAT 215 Lecture Notes - Lecture 8: Adrenal Gland, Norepinephrine, Cranial Nerves
Document Summary
Autonomic nervous system (ans): motor subdivision of pns, the involuntary nervous system. Visceral motor (smooth muscle, cardiac muscle, glands) : indicates the targets: smooth muscle, cardiac muscle, glands. Pathways for motor output: two-neuron chain, preganglionic neurons with cell bodies in cns: preganglionic, either brain or spinal cord. Will affect the same target with opposite functions. Blood vessels receive sympathetic innervation but no parasympathetic. Preganglionic axons originate from the cell bodies in the spinal cord. Origin: spinal cord segment t1-l2 (also called thoracolumbar division) Widely distributed to many parts of the body: Generally is responsible for situations in which energy needs to be expended (the fight or flight phenomenon) : metabolism increases, become more alert, overall response is to be able to deal with the emergency. Parasympathetic: preganglionic axons are constant from opposite ends of the cns, at the brainstem and s2 to s4. Origin: brain stem and spinal cord 2,3,4 (also called craniosacral division)