CNS test 2-Spinal reflexes Flashcards
predictable response to a stimulation that is unconscious, few synapses are involved and does not go up to the cortex
spinal reflex
functional unit of the motor system, and alpha motor neuron with all its branches and muscle fibers it innervates.
motor unit
parts of a motor unit (4)
- NMJ
- axon
- cell body
- muscle fibers
as we age we lose motor neurons centrally and peripherally from the ______ and _____
brain stem, spinal cord
as we age movement becomes less ____
precise (lose motor neurons centrally and peripherally)
enlargement at the end of an axon that fits inside of a groove in the muscle, achetylcholine excites it
motor end plate (sole plate)
sensory innervation of skeletal muscle (2)
extrafusal fibers
muscle spindle
extrafusal fibers
ordinary muscle cells constituting the majority of the muscle, their stimulation results in muscle contraction, alpha motor neurons
Muscle Spindle
composed of intrafusal fibers, dispersed throughout the muscle.
muscle spindle has __-__ fibers
2-12
all nuclei in muscle spindle fibers are located in _______ and ______
central non-contractile region
contractile portion at ends
______ fibers wrap around the nuclear region of spindal fibers
afferent
_____ fibers go to contractile region of
efferent (gamma motor neurons)
primary afferent responds to
The rate of stretch
secondary afferent responds to the
degree of stretch