Question

As actin and myosin filaments slide past each other during muscle contraction, i. actin filaments shorten, while myosin filaments do not ii. myosin filaments shorten, while actin filaments do not iii. both actin and myosin filaments shorten iv. neither actin nor myosin filaments shorten The Ca^2+ required for skeletal muscle contraction i. is released from the sarcoplasmic reticulum. ii. enters the cell due to the opening of voltage regulated Ca^2+ channels from the T tubules. iii. is actively transported into the cell. iv. is released from mitochondria Myocardial cells exhibit a plateau phase instead of quickly repolarizing. This is due to i. inward diffusion of calcium through slow Ca^2+ channels. ii. inward diffusion of sodium through fast Na^2+ channels. iii. inward diffusion of potassium through voltage-gated K^+ channels. iv. outward pumping of sodium by the Na^+/K^+ pump. Cardiac output is equal to i. stroke volume cardiac rate. ii. stroke volume cardiac rate. iii. stroke volume cardiac rate iv. stroke volume x cardiac rate Hydrostatic pressure is _____ and colloid osmotic pressure is _____ at the arterial end of a capillary i. higher, higher ii. higher, lower iii. lower, lower iv. lower, higher Diffusion rate across the respiratory membrane is rapid because i. there are about 760 square feet of alveoli membrane. ii. alveoli are one cell thick. iii. the air-blood barrier is two cells thick. iv. All of the choices are correct. Name the various types of membrane transport mechanisms found in the body. What are the three characteristics of facilitated diffusion?

Answer 1

Ans-6 (i) the actin filament get shorten while myosin remain constant because during contraction actin muscles slide toward myosin.A band remain constant

Ans-7 (i) it is released from sarcoplasmic reticulam from where it binds with troponin.

Ans-8 (i) the l type of calcium ion channel are responsible for plateau effect.

Ans-9 (iv) stroke volume × cardiac rate