Case 9 - Histology Flashcards
what are the functions of skeletal muscle
moves and stabilises the skeleton
forms sphincters in digestive and urinary tracts
involved in respiration
characteristics of skeletal muscle
long, cylindrical cells
striated
multiple, peripherally located nuclei
innervated by somatic nervous system
what is the endomysium
connective tissue layer surrounding a single muscle fibre
what is a fascicle
bundle of muscle fibres
what is the perimysium
connective tissue layer surrounding a fascicle
what is a muscle
a group of fascicles
what is the epimysium
connective tissue layer surrounding a muscle
what are the features of the type I muscle
it is the slow twitch muscle
involved in aerobic respiration
generate more ATP for continuous extended contraction
fire more slowly
resist fatigue
rich In mitochondria and myoglobin - appear dark red in vivo
what are the features of the type II muscle
it is the last twitch muscle
use for anaerobic respiration
good for short bursts of strength and speed
fatigue more quickly
few mitochondria and little myoglobin
what is type IIa
intermediate fast twitch, use both aerobic and anaerobic respiration
what is type IIb
use only anaerobic
what is the muscle spindle
has sensory stretch receptors - detect fibre length
lies parallel to the muscle fibres
what does the muscle spindle consist of
spindle cells - nuclear bag fibres and nuclear chain fibres surrounded by an internal capsule
Internal capsule within fluid filled space surrounded by external capsule
Sensory nerve ending wrapped around spindle cells - detect stretch
what does the reflex response do
shortens the muscle
where do spindle cells also receive motor innervation from
CNS by gamma neurones - regulates sensitivity of receptor
