The movement of which two ions is responsible for maintaining the plateau phase of the action potential of contractile cardiac muscle cells? Select one: a. Ca2+ and Na+ b. Ca2+ and K+ c. Na+ and Cl- d. Na+ and K+ e. K+ and Cl-

1. In ventricular fibrillation, there is no pattern visible in the EKG. What does this mean in terms of contraction? A. contraction will have no visible pattern either and the ventricles will be unable to eject much blood B. the pattern doesn't matter; contraction of the ventricles will not be affected as long as ventricular myocytes continue to depolarize and depolarize C. the ventricular myocytes will be unable to contract C. contraction will become constant and ventricles will be unable to fill with blood   2. Which structure follows depolarization of the SA Node and atria in the cardiac conduction system? A.ventricular myocytes B.AV Node C.left and right bundle branches D.AV bundle E Purkinje fibers   3. Hypertension increases afterload for the heart which in turn  A. increases Stroke Volume B. decreases Stroke Volume C.increases Cardiac Output D.increases Venous Return

Patient in renal failure develops hyperkalemia so that his extracellular [K+] increases from 4.5 mEq/L (normal) to 6.5 mEq/L. What will happen to the resisting membrane potential (RP) of his cardiac myocytes? a. it will depolarizeb. it will hyperpolarizec. there will be no change since K+ channels are freely permeabled. there will be no change since Na+ channels are closede. it will polarize

Epinephrine is the chief neurotransmitter of the sympathetic nervous system. What effect would you expect it to have on the contractions of cardiac muscle? Explain.

Why does the right ventricle have a bicuspid valve?   a. The low pressure generated by the right ventricle is best suited to bicuspid valve compared with a tricuspid valve b. The high pressure generated by the right ventricle would be better controlled by a bicuspid compared with a tricuspid valve c. Only a short pumping distance to the lungs is required for the bicuspid valve d. The right ventricle does not have a bicuspid valve

Drugs known as calcium channel blockers prevent Ca++ movement through Ca++ channels. Explain two ways that this action can lower blood pressure. Why are neurons and other cells unaffected by these drugs?

cardiac output depend on what two factor  a. stroke volume and stroke power  b. cardiac rate and cardiac rhythm  c. cardiac rate and stroke volume  d. blood density and blood volume    2. which is the following is not matched correctly    a. musclar ( distributing artieres - mainly made up of smooth muscle ( found in tunica medial )  b. vasa vasorum : small blood vessles that helps in nourishing particularly large arteries and veins  c. arterioles - relatively large and thick vessels that controls the flow of blood leaving the heart d. elastic (conducting ) arteries - well supplied with elastin to maintain pressure ) has all 3 tunica

Patients with a history of heart failure often get this history from chronic hypertension. Chronic hypertension leads to a condition called hypertrophic heart disease, or hypertrophic cardiomyopathy. This means that the heart muscle gets bigger, allowing less room for it to fill with blood. If these patients take beta blockers, such as metoprolol, it will benefit them because the heart will not overwork and grow in size. However, if a patient has pulmonary edema, how could the beta blocker make this patient worse?

If heart rate is the independent variable and diastolic blood pressure is the dependent variable, which graph would best describe their relationship? Please thoroughly explain the effect on the dependent variable if the independent variable increases so I can fully understand the concept.

In which of the following situations is calcium moving through a channel in the pacemaker membrane driven by concentration but against charge? O during the repolarization phase of the action potential, just before the channel closes O during the depolarization phase of the action potential, just after the channel opens O never O at all times that sodium is moving through the membrane O during the repolarization phase of the action potential, just after the channel opens O during the depolarization phase of the action potential, just before the channel closes O during the pacemaker potential, just before the funny channel closes