Muscle Contraction Flashcards
Muscle Fiber (myocyte/myofiber) Type I
slower contraction, more mitochondria, does not fatigue as fast
Muscle Fiber (myocyte/myofiber) Type II
faster contraction, less mitochondria, fatigue quickly
Titin
hold myosin in place and connect them to the Z disk
Thick Filaments
Myosin [2 heavy chains, 2 light chains]
Thin Filaments
Actin (F-actin monomers)
Fascicle
group of myofibers surrounded by perimysium
Muscle Fiber/Myofiber/Myocyte
made of myofibrils (chains of sarcomeres linked together) surrounded by endomysium
Muscle
group of fascicles surrounded by epimysium
Sarcomere
contractile unit of muscle made of actin and myosin
What is enclosed by perimysium?
Fascicle: Group of myofibers
What is enclosed by endomysium?
Muscle fibers: a group of myofibrils
What is enclosed by epimysium?
Muscle: Group of fascicles
I-Band
Part of sarcomere from Z-disk to end of Titin (or beginning of myosin)
Space of no myosin
A Band
Length of myosin
H band
space between actin fibers where there is no actin
M line
attachment site for myosin (middle of sarcomere)
Z Disk
Separates sarcomeres
Transverse (T) Tubules
membrane system that conveys electrical impulses from the sarcolemma into the cell (electrical wiring)
Sarcolemma
membrane around each muscle cell
Terminal Cisternae
a flattened sac of SR on each side of transverse T tubule
Tirad
T Tubule + 2 Terminal Cisternae
End feet
Connect T tubules with SR to allow Calcium to be released
Rule for muscle innervation
Muscle fibers are only innervated by a single nerve but a single nerve can innervate multiple fibers
Neuromuscular Spindle Apparatus
System built into muscles to prevent over-stretching
Extrafusal and Intrafusal fibers
Extrafusal fibers
Contract external muscle in response to Ia Fibers
Alpha motor neurons of anterior horn
Intrafusal fibers
Sense rate and length of change inside muscle
Gamma motor neurons of anterior horn
Type Ia Fibers
sense stretch and rate of change in intrafusal fibers
Sensory neurons of dorsal horn
Multipolar neuron
multiple dendrites and one axon (typical neuron)
Bipolar neuron
single dendrite (multiple extensions) and one axon
Pseudounipolar
One cell process with a single dendrite and axon branch (cell body is not in line with rest of neuron)
Myelin wraps what?
Single Axons
