IPHY 3410 Final Exam Material

Spinal Cord

Runs from medulla oblongata to level of vertebrae L1 or L2

Spinal cord function

Connects PNS of regions inferior to head with brain

White matter

axons create columns, form sensory/motor pathways

Gray matter

reflex pathways

What structures protect the spinal cord?

Meninges, bone, subarachnoid space, epidural space

Ascending tracts

composed of sensory interneuron axons

Descending tracts

composed of motor interneuron axons

Ventral Horns

neurons associated w/ motor functions leave spinal cord here

Dorsal horns

neurons associated w/ sensory functions enter spinal cord

Lateral Horns

visceral motor neurons (ANS)

Somatic and Visceral sensory

Dorsal root ganglia

Somatic Motor

cell bodies in ventral horns exit thru ventral root.

Visceral motor

cell bodies from lateral horns exit thru ventral root

Reflex arc

automatic and fast motor responses that don’t require input

from brain

Monosynaptic reflex

axon terminals of sensory neurons synapse directly w/ motor neuron within spinal cord

Polysynaptic Reflex arc

axon terminals of sensory neurons connected via one or more interneurons to a motor neuron

Sensory receptors

can be simple (dendrites/free nerves) or complex, classified by functionality

Mechanoreceptors

respond to distortion caused by pressure changes, vibration. Example, Meisner’s corpuscles and root hair plexus

Proprioceptors

also a mechanoreceptor, nerve ending wraps around muscle fibers, tendons, or joints that respond to stretch → allows for awareness of movement

Thermoreceptors

Free nerve endings that respond to temperature changes

Chemoreceptors

respond to different chemicals (taste buds)

Photoreceptors

respond to light (retina)

Nociceptors

pain receptors, free nerve endings that respond to mechanical, thermal or chemical stimuli

What neurotransmitter is released at neuromuscular junction with skeletal muscle

Acetylcholine

What NT is released at synapse w/ smooth

muscle cells

Ach or NE