EXAM 3 Flashcards
what is reverse muscle action
when origin moves towards insertion
describe a first class lever
Effort –> Fulcrum –> Load like a teeter totter
example of a first class lever
Neck muscle –> atlas –> skull
describe a second class lever
Fulcrum –> Load –> Effort wheelbarrow
example of a second class lever
metatarsals, body weight, calf muscles
describe a third class lever
Force –> Effort –> Load
example of third class lever
elbow joint –> biceps muscle –> weight in hand
what is the name of the outer covering of the muscle
epimysium
what covers the fascicles of the muscle
perimysium
what covers muscle fibers
endomysium
are skeletal muscles mono or multi nucleate
multinucleate
how do muscles fibers grow by hypertrophy or hyperplasia
hypertrophy
what is the sarcoplasm
cytoplasm of skeletal muscle cell
what is the sarcolemma
cell membrane of muscle cell
what is the sarcoplasmic reticulum
equivalent of smooth er in muscle cell
what is the myofibril
fiber that contains sarcomere
what is the functional unit of a muscle cell
sarcomere
what are t tubules
high ways where the action potential travels through
One sarcomere goes from ___ to ___
z-disk to z-disk
what does the A band comprise of
actin + myosin
what does the I band consist of
z disc to mysosin, only actin
what does the H zone comprise of
only myosin
what is the M line
middle line
what are the two regulatory proteins
tropomyosin and troponin
which regulatory protein binds with calcium
troponin
which regulatory protein moves out of the way to expose the myosin binding site
tropomyosin
what are the five structural proteins in the sarcomere
titin, dystrophin, nebulin, myomesin, alpha actin
describe titin
spans from z disc to m line and stabilizes myosin, gives elasticity
describe dystrophin
links actin to the sarcolemma helps transmit tension to tendons
describe nebulin
spans length of actin, anchors actin to z disc
describe myomesin
found in M- line, hold titin and myosin in position
how does the sarcomere change length during contraction
it shortens
is the I band reduced, lengthened, or stays the same during contraction
shortened
How does the A band change length during contraction
stays the same
define excitation
the events that transmit an electrical signal from a motor neuron to a muscle fiber
when ATP binds to the myosin heads does this make them detatch or attach
detatch
describe relation of a muscle
active Ca transporters remove Ca from sarcoplasm, Ca levels drop and titin brings sarcomere to resting position
what are the 3 sources of energy from muscles
creatine phosphate, anaerobic, aerobic respiration
how long does the body use creatine phosphate for
10-15 seconds
how long does the body use anaerobic respiration
up to 2-3 minutes
how long does the body use aerobic respiration
long long time
describe SO fibers Type I
called slow because contraction cycle is slower, many mitochondria, produce energy by anaerobic respiration, dont fatigue easy, red in color
describe FOG fibers Type IIA
called fast bc contraction cycle is faster, many mitochondria, produce energy by both anaerobic and aerobic respiration,
describe FG Type IIX
called fast bc contraction cycle is faster, little mitochondria, energy only from anaerobic respiration
what is spatial summation
increasing motor unit recruitment
what is temporal summation
increasing the frequency of stimulation
define isometric contraction
generates tension but does not shorten
define concentric contraction
when the tension generated is sufficient enough to move the load, the muscle shorten
define eccentric contraction
as tension decreases, the load exceeds the tension, the muscle lengthens
