Anatomy of Muscle
What structure is a continuation of the sarcolemma and carries the action potential deep into the muscle fiber?
T-tubule
What molecule is responsible for setting up the large concentration gradients of sodium and potassium across the sarcolemma?
The difference between a channel and a pump is that a pump requires _____________ and a channel does not.
ATP
What is the function of myoglobin?
oxygen storage
The entire action potential fits into which phase of a twitch?
latent phase
What is the name of the connective tissue wrapping around a muscle fascicle?
perimysium
A cell membrane with a voltage of -110 mV would be considered what?
hyperpolarized
Crossbridge cycling requires repeated conformational changes of what protein?
myosin
What is the advantage that oxidative phosphorylation has over anaerobic fermentation?
it is more efficient--creates more ATP
What is the difference between treppe and incomplete tetanus?
Treppe still has complete relaxation in between twitches, incomplete tetanus does not
What is the name of the band of the sarcomere that contains only myosin?
H-zone
What happens when a cell depolarizes to threshold?
voltage-gated channels open
Calcium release is important because it binds to what protein, causing a conformational change?
troponin
The enzymes creatine kinase and myokinase are involved in which pathway of ATP synthesis?
Direct phosphorylation/the phosphagen system
How do you describe an exercise where the muscles are generating tension, but are not changing in length?
Isometric
What is the name of the structure that stores calcium ions when a muscle fiber is at rest?
Sarcoplasmic reticulum
Ligand-gated channels open when _______ binds to its receptors.
Acetylcholine, ACh
Why is it important for the action potential to travel deep into the cell?
it causes the release of calcium
Which ATP synthesis pathway is going to be producing most of the energy 45 seconds into exertion?
fermentation/anaerobic pathway
You are doing a biceps curl and are in the phase where you are lowering the weight (slowly and with control!). What kind of contraction is your biceps doing now?
Eccentric
The contractile organelle, containing many sarcomeres end-to-end, is called what?
What is a circumstance that could create an especially large action potential?
An action potential is always the same size.
Which molecule will re-cover the binding sites on actin to create muscle relaxation?
tropomyosin
What is the name of the glucose storage molecule in humans?
glycogen
A muscle has an indirect attachment at its insertion. This means that it has what structure on that end?
a tendon