When the doctor listened to Janet's heart, he heard 'lub-hiss, lub-hiss' instead of the normal 'lub-dup' sounds. The hiss is most likely due to _________ . (Explain your answer.)a. a defective atrioventricular (AV) valveb. a damaged pacemaker (SA node)c. a defective semilunar valved. high blood pressure

Which of the following decreases blood pressure?

A mutation that results in a nonfunctioning nitric oxide receptor would cause __________.

Blood pressure is highest in _________ , and blood moves most slowly in _________ .a. veins; capillariesb. arteries; capillariesc. veins; arteriesd. arteries; veins

Pulse is a direct measure ofa. blood pressure.b. stroke volume.c. cardiac output.d. heart rate.

Paul's blood pressure is 150/90. The 150 indicates _________ , and the 90 indicates _________ . a. pressure in the left ventricle; pressure in the right ventricle b. pressure during ventricular contraction; pressure during heart relaxation c. systemic circuit pressure; pulmonary circuit pressure d. pressure in the arteries; pressure in the veins

Which of the following initiates the process of blood clotting? a. damage to the lining of a blood vessel b. conversion of fibrinogen to fibrin c. attraction of white blood cells to a site of infection d. conversion of fibrin to fibrinogen

Blood flows more slowly in the arterioles than in the artery that supplies them because the arterioles a. have thoroughfare channels to venules that are often closed off, slowing the flow of blood. b. have sphincters that restrict flow to capillary beds. c. are narrower than the artery. d. collectively have a larger cross-sectional area than does the artery.

Explain why a person who survives a myocardial infarction might need to have an artificial pacemaker implanted.