Microscopic Muscle fiber Flashcards
What is a cell at rest, where is more negative
on the inside
what does the sarcolemma do
it is a cell membrane that separates charges
what are transverse tubules
regions of sarcolemma that dip into muscle cell, they transmit APs deep into the cell
what transmit ap deep into cell
transverse tubules
what are the 4 things in sarcoplasm
myofibrils
sarcoplasmic reticulum
mitochondria
glycogen granules
what are myofibirls
bundels of myofilaments, like actin and myosin
they run the length of the cell and anchor to cell membrane location of contraction
what does the sarcoplasmic reticulum do
sequesters Ca ++ and keeps cytoplamic Ca++ low at rest
what are the 2 things in sarcoplasmic reticulum
terminal cisternae
triad
what are terminal cisternaes
part of the sarcoplasmic reticulum that are bloated areas of SR, located adjacent to t. tubules.
what do mitochondria benefit in the sarcoplasm
the breakdown of glucose
rank groupings from largest to smallest
faascicle, fiber, myofibril, myofilament
what is the sarcomere
myofilaments organized into repeating functional units
what is the h zone
part of the a band that is only myosin
what is the a band
region that contains the entire myosin molecule
what cuases striations
arrangement of contractile proteins,
differences in size, density, and distribution of actin and myosin
what is the thin filament
actin
what is the active site of actin
the myosin binding site
nebulin def
holds g actin together
what is tropmyosin
a linear filament protein that at rest, covers all active sites (2 strands of it )
troponin info
a globular protein
what does troponin do
binds ca++ and causes a conformational change.
its task is to pull tropomyosin away from the active site
what is the thick filament
myosin
what are the 3 parts of myosing
tail
head
hinge
tail of myosin vs head and hinge
tail is the linear part, where myosin molecules anchored together
head binds actin if active site is uncovered and forms cross bridge
the hinge is the ability to shift
what binds actin if the active site is uncovered
the myosin head
what is titin
a protein that anchors myosin to z line
what is the fxns of titin
maintains proper alignment between actin and myosin
prevents extrememe stretching
recoil after stretching
what is the sliding filament theory
individual myofilaments do not change length, and the fact that contraction is due to myofilaments sliding past one another.
can filaments pass the z or m line
no
what are the 3 components of the neuromuscular junction
synaptic knob
synaptic cleft
motor end plate
what is the synaptic knob
wider portion of axon that comes up to muscle fiber
what do synaptic vessicles contain
neurotransmitters
what is the synaptic cleft
the physical gap between neuron and muscle fiber
where neurotransmitters diffuse to muscle fiber
what is the motor end plate
region of muscle fiber that has neurotransmitter receptors (folded appearance
