ID: A 42. After birth, the ductus venosus closes and: allows blood to flow to th
ID: 3505990 • Letter: I
Question
ID: A 42. After birth, the ductus venosus closes and: allows blood to flow to the lungs. allows blood to flow to the liver. preven a. b. c. d. ts blood from moving from the right to the left atrium. stops blood flow to the placenta. 43, Ifthe AV nod beats per minutes. a. 10 to 30 b. 20 to 40 c. 30 to 50 d. 40 to 60 e were forced to assume pacemaker activity, the resulting pulse rate would be 44. Which of the following most accurately describes what is measured by an electrocardiogram? a. Electrical conductivity b. Number of contractions per minute c. The speed and strength of contractions d. Any abnormal functioning 45. A cause of a heart murmur may be: a. incomplete closing of a valve. b. incomplete contraction of the atria. c. narrowing of a valve (stenosis). d. both A and C. 46. Peripheral resistance is affected primarily by a. the length of myocardial fibers. b. blood viscosity and the diameter of arterioles c. the capacity of the blood reservoirs. d. elasticity of the heart. 47. Which of the following is not a mechanism that increases blood volume and therefore venous return of blood to the heart? a. Antidiuretic hormone b. Aldosterone c. Atrial natriuretic hormone d. Renin-angiotensin mechanism 48. The greatest resistance to blood flow occurs in the a. arteries. b. arterioles. c. venules. d. capillaries.Explanation / Answer
42.B
43.d.40-60 beats per minute.
44.a.electrical conductivity
45.d .both A and C .
46.B.
blood viscosity and the diameter of arterioles.
47.C.
atrial natriuretic hormone.
48.B.
arterioles.