Which statement about stroke volume (SV) is false: a. an increases in venous ret

Question

Which statement about stroke volume (SV) is false: a. an increases in venous return to the heart will cause a decreases in action to myosin crossbridging in myocytes b. the release of acetycholine on the heart will cause a decreases in SV c. an increases in a pressure to above 160 mmHg will cause a decreases in SV d. the drug digitalis increases the intracellular concentration of calcium, thereby increasing contractility and SV e. the physical stretching of cardiae myocytes causes myocytes to contract with more force Which statement about the neuronal action potential is true: a.at threshold, the sodium inactivation gate closes and then the sodium activation gate opens b. first there is an outflow of potassium, followed by an inflow of the sodium c. the drug physostigmine blocks the opening of the voltage-gated sodium channel d. the potassium activation gate is slower to move than sodium activation gate e. the movement of sodium into the cell causes a rapid repolarization Which statement about the role of calcium ions in skeletal muscle contraction is false: a. calcium is actively transported out of the muscle cell and out of the sarcoplasmic reticulum b. calcium binds to troponin to cause a conformational change in tropomyosin c. in the motor neuron, calcium causes synaptic vesicles to go through exocytose d, when the dihydropyridine- ryanodine channel opens, calcium leaves the sarcoplamic reticulum e. calcium present in the sarcomere causes myosin-to-actin cross-bridging Which of the following causes depolarization in neurons: a. chemically-gated channels that cause a closing of chloride channels. b. the electrogenic sodium/potassium ATPase pump c. voltage-gated potassium channels d. passive potassium channels e. inhibitory chemically-gated channels Which statement about excitatory chemically-gated channels on dendrites true: a. the depolarization on the dendrite has a greater effect than a similar depolarization to the soma b. there is redused resistance to the flow of sodium ions along the dendrite the resistance to the soma c. the resistance to ion flow inside dendrites is low because dencrites are thin d. excitatory chemically-gated channels on the dendrites allow the inward diffusion of sodium ions e. depolarizations are weakened because the dendrites are very leaky to calcium Which the following will cause a decrease in cardiac stroke volume: a. an increase in venous blood return to the heart b. a stretching of the cardiac myocytes c. an injection of norepinephrine that increases arterial pressure to 180 mmHg d. an increase in sympathetic nerve activity to the heart e. a large caffeine dose following consumption of 5 energy drinks

Explanation / Answer

The answers are as follows:

7.c

8. a

9. b

10. a

11. C - Voltage gated pottasium channels

12. d

13.C

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