Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
16 Cards in this Set
- Front
- Back
|
Explain Ca's action in contraction of skeletal mm
|
Action potential -> Ca released from terminal cisternae of SR -> Ca binds to troponin --> moves blocking action of tropomyosin -> exposes active sites -> myosin cross bridges alternately attach to actin and detach pulling in --> contraction this releases ADP
|
|
|
What ends the contraction of a skeletal mm
|
The Ca is retaken up by the SR and as the concentration decreases Ca releases from the troponin - ATP reattaches to myosin head
|
|
|
What makes up the thin filaments of skeletal mm
|
actin
|
|
|
what makes up the thick filaments of skeletal mm
|
myocin
|
|
|
What band do the thin filaments make in a sarcomere
|
I band
|
|
|
What band do the thick filaments make in a sarcomere
|
A band
|
|
|
What is tropomyosin
|
helical protein that blocks the binding of myosin to actin
|
|
|
What is an isotonic contraction
|
Mm shortens while moving a load maintaining constant tension
|
|
|
What is an isometric contraction
|
Increase in tension in a mm while contracting - so mm does not shorten
|
|
|
What is a force-velocity curve
|
velocity at which a mm fiber shortens dec w/inc loads. Shortening velocity is max when there is no load and 0 when max load = isometric tension.
|
|
|
What is a length-tension curve
|
change in length of fiber b4 contraction can alter the amount of tension developed by a mm fiber, thus its strength. When max cross bridges can be achieved - greatest mm tension.
|
|
|
What are the 3 phases of a twitch
|
Latent period - Ca released, slack removed from mm, no tension detected
Contraction - beginning of shortening to peak tension Relaxation period - Ca pumped back into SR. mm tension dec and mm returns to original shape |
|
|
What are type I/slow twitch fibers (skeletal mm) - slow oxidative
|
color - red, high myoglobin, high mitochondria, high blood supply. Slow acting myocin ATPases, contract slowly. Good for long distance runners. Efficient and high endurance. Thin, not a lot of force.
|
|
|
What are type IIB/fast twitch fibers (skeletal mm) - fast glycolytic
|
Large, pale (white) fibers. Fast acting myocin ATPases, contract rapidly. low mitochondria and myoglobin. Large glycogen reserves. Depend on anaerobic pathway for ATP. Lactic acid accumulates. Fatigue quickly. Powerful contraction. Rapid, intense movements for short spurts.
|
|
|
Type IIA/fast twitch fibers (skeletal mm) - fast glycolytic-oxidative
|
Red to pink. Btw white and red fibers in size. Have fast-acting myocin ATPase and contract quickly like white fibers. They are O2 dependent like red fibers. High myoglobin and more of an aerobic capability than white fibers.
|
|
|
How is contraction typically induced in smooth muscle
|
stretching of the mm and propagation of nerve impulse from cell to cell
|
