Unit 3 - A & P Module - Skeletal Muscle Properties Structure and Function Flashcards
Skeletal muscles with the most endurance (resistance to fatigue) are __________ in color.
red
The latent period is due to the time it takes for __________.
excitation-contraction coupling
Thick filaments have __________.
ATPase activity and actin binding sites
The troponin complex in thin filaments can bind __________.
tropomyosin, calcium, and actin
The A band contains __________.
an area of partial overlap between thick and thin filaments
Muscle relaxation requires __________.
ATP
When the arrival of an action potential at the muscle cell membrane triggers the release of calcium from the sarcoplasmic reticulum, this process does not go on indefinitely because __________.
the rising concentration of cytosolic calcium triggers the closure of calcium channels in the sarcoplasmic reticulum
When an action potential travels along the sarcolemma of a muscle cell __________.
DHP receptors in the T-tubule undergo a conformational change and Ca2+ flows down its concentration gradient through the ryanodine receptors
After the myosin ATPase hydrolyzes ATP into ADP + Pi, __________.
the two products stay attached to the myosin head, the myosin head is cocked and binds to a different G-actin molecule, ready for the power stroke
The functional unit within a muscle fiber is called a sarcomere. Which of the following does not make up part of the sarcomere?
Myofibril
The neurotransmitter that signals the contraction of skeletal muscle fibers is __________.
acetylcholine
During complete tetanus __________.
cytosolic calcium levels are high enough to saturate all the troponin molecules, action potential frequency is higher than the fused muscle twitch frequency, and action potential frequency is higher than the fused muscle twitch frequency
Put the events of the crossbridge cycle in the correct order, starting with the binding of myosin to actin:
a. binding of ATP
b. release of Pi
c. release of ADP
d. power stroke
b, d, c, a
When myosin is bound to actin during the crossbridge cycle __________.
calcium is bound to the troponin complex and myosin is in its high-energy form
