41.) If a skeletal muscle was bathed in acetylcholine a.) it would contract b.)

Question

41.) If a skeletal muscle was bathed in acetylcholine a.) it would contract b.) action potentials would form in T tubules c.) Ca2" ions would be released into the cytoplasm of muscle cells d.) actin subunits would be available to myosin heads e.) all of the above 42.) Epinephrine and norepinepherine, a.) speed up heart rate b.) slow down digestion c.) are released by sympathetic neurons d.) both a and b e.) a, b, and c 43.) Intercalated disks a.) allow electricity to flow between cardiac muscle cells b.) form cytoplasmic connections between cardiac cells c.) coordinate heartbeats d.) both a and b e.) a, b, and c 43.) This muscle type lacks sarcomeres. a.) cardiac muscles b.) skeletal muscles c.) smooth muscles d.) both a and b e.) none of the above 44.) Voluntary contraction is characteristic of a.) cardiac muscles b.) skeletal muscles c.) smooth muscles d.) both a and b e.) a, b, and c 45.) Slow muscle fibers a.) appear white b.) derive ATP via glycolysis c.) have high myoglobin concentrations d.) both a and b e.) a, b, and c

Explanation / Answer

41. Ans-b) action potentials would form in T tubules

When skeletal muscle was bathed in acetylcholine, then the acetylcholine receptor, a sodium channel opens as bound to acetylcholine. This acetylcholine receptor depolarizes the plasma membrane after opening and result in the opening of voltage-gated sodium channels and initiating an action potential. The action potential become invaginates into the center of the muscle cell to form T-tubules that run parallel to the sarcoplasmic reticulum of muscle cells.

42. Ans-a) speed up heart rate

Explanation:

Epinephrine and norepinephrine cause increasing the heart rate, blood pressure, cardiac output and blood glucose levels.They are secreted by medulla of adrenal glands.

43. Ans- e) a, b and c

Explanation:

Intercalated disks are found in cardiac muscles that contain the gap junction and desmosomes. This gap junction channels form a cytoplasmic bridge between the neighboring cells that allow flowing electrical current between cell-to-cell. and small molecules Intercalated discs are microscopic identifying features of cardiac muscle that required for coordinated muscle contraction and maintenance of circulation.

44. Ans-c. smooth muscles

Explanation:

Smooth muscle cells do not contain sarcomeres. In the smooth muscles, actin filaments are arranged obliquely in the cytoplasm.

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