In: Anatomy and Physiology
Which off the following does NOT occur during skeletal muscle contraction?
Titin fibers compress
Actin and myosin shorten
Sarcomers shorten
2. Action potential propagated along the sarcolemma stimulate ___________ located on transverse tubules.2.
Nicotinic receptors
Ryanodine receptors
DHP receptors
3. Which of the following does not occur during the "Excitation" of a skeletal muscle?
Group of answer choices
The cell membrane depolarizes
ATPase on myosin heads split ATP
The myosin head binding site on actin is exposed
The passive force of contraction increases
4. What happens as an IMMEDIATE result of Ryanodine receptors on the sarcoplasmic reticulum being stimulate?
Ryanodine receptors simulate DHP receptors on T-tubules
Myosin cross bridges are formed
Calcium ions diffuse out of the saroplasmic reticulum
5. Why does lactic acid produced during anaerobic metabolism cause fatigue?
Because H+ from lactic acid interfers with crossbridge formation
Because lactic acid produced duirng anaerobic metabolism produces only 2 molecules of ATP
Because the myosin head is denature by lactic aci
1. Actin and myosin shorten
Sarcomere shortens but actin and myosin do not shorten bu tslide past each other in muscle contraction.
2. DHP receptors
The influx of extracellular Ca2+ in cardiac muscle takes place either through the dihydropyridine receptors (DHPRs), L-type voltage sensitive Ca2+ channels, located in plasmalemma and T-tubules.
While, ryanodine receptors are located in the sarcoplasmic/endoplasmic reticulum membrane and are responsible for the release of calcium from intracellular stores during excitation-contraction coupling in both cardiac and skeletal muscle
3.The passive force of contraction increases
Passive forces involves structures inside the muscle fiber that elongate elastically when they are pulled apart. Active force of contraction increases in excitation of skeletal muscles.
4.Calcium ions diffuse out of the saroplasmic reticulum
Ryanodine receptors mediate the release of calcium ions from the sarcoplasmic reticulum and endoplasmic reticulum during muscle contraction.
5.Because lactic acid produced duirng anaerobic metabolism produces only 2 molecules of ATP
Hydrogen from lactic acid reduces the pH which can cause muscle fatigue