Sensory receptors Flashcards
What is a muscle spindle?
structure in muscle belly that monitors change in muscle length
Intrafusal muscle fibers are what kind of cell?
specialized skeletal muscle
What are the two types of intrafusal muscle fibers?
“Nuclear bag fibers
Nuclear chain fibers”
What is the difference between Nuclear bag fibers and nuclear chain fibers?
nuclei in bag fibers are able to move, chain fiber nuclei only stretch
T/F Nuclear bag fibers have actin, but no myosin
False, Intrafusal muscle fibers have neither actin nor myosin, only nuclei
T/F Intrafusal muscle fibers are enclosed within oval-shaped connective tissue capsules
False, they are enclosed within spindle-shaped connective tissue capsules
T/F Primary ending (sensory nerve endings type 1a) are wrapped around the center of both nuclear bag fibers and nuclear chain fibers?
TRUE
What type of sensory nerve ending is wrapped around the center of both nuclear bag and nuclear chain fibers?
Type Ia
What type of sensory nerve ending is wrapped around the center of only nuclear chain fibers?
Type II
What are the two types of Gamma motor nerve fibers?
“Gamma-dynamic (gamma-d)
Gamma-static (gamma-s)”
Which motor nerve fiber innervates nuclear bag fibers?
Gamma-d
Which motor nerve fiber innervates nuclear chain fibers?
Gamma-s
