muscle 1 Flashcards
voluntary muscles
connected to bones and present in sphincters with some exceptions
skeletal muscles.
striated
elongated cell
multiple peripheral nuclei
parallell musvle fibre (cell)
sarcoplastic reticulum (modified ER) and terminal cristernae contaiing Ca
t tubule
myofibrils
involuntary muscle- cardiac
branching cell
single central nucleus
straited
present within the heart
invountary muscle- smooth muscle
present in visceral organs, blood vessels, eye (vision accomodation pilorecetor)
non striated
spindle shaped cell
single central nucelus
what are coluntary muscles covered by
dense connective tissue
t tubeule
axon like fibre that transmits action potential into muscle
bands of myofibril
alternating dark (A bands) and light bands (i bands) giving appearance of straiations. regular arrangement of thick and think fillaments which slide against each other changing muscle length
functional unit of striated muscle
sarcomere that is found between two Z lines
z lines
connects thin fillaments of two adjoining sarcomeres
a band
made up of thick fillaments along with portions of thin fillaments that overlap on both ends of thick fillaments
i band
constis of remiaing portion of think fillaments that do not project into a band
h zone
lighter area within middle of a band where thin fillaments do not reach
m line
extends vertically down middle of a band within centre of h zone
where do motor neurons project from and thier endings
the spinal chord and the axons divide into multiple endings. each ending synapses with one muscle fibre cell to form one end place per cell
action potentials and what they contract
each action potential transmitted through each motor neuron can contract multiple muscle fibre cells within the muscle bundle
how many types of muscle fibres innervate the same muscle
two
slow twitch- innervated by a2 small diameter low threshold motor neurons
fast twitch- innervated by a1 large diameter high threshold motor neurons