AP Biology : Understanding Heart Anatomy

Study concepts, example questions & explanations for AP Biology

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Example Questions

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Example Question #21 : Circulatory System

The migration of cells is necessary for proper development during fetal life. At around the third week of fetal development, hematopoietic stem cells can be found in the yolk sac as well as in the mesoderm of the aorta, the gonads and in the mesonephros. At around the 3rd month, these stem cells migrate to the liver with some to the spleen and the lymph node. At around the 4thmonth, these cells then migrate to the bone marrow.

When taking a cross section of a bone, one will notice that some bone marrows are red while others are fat. Yellow bone marrows are inactive stem cells with the majority being fat cells. Active bone marrows are red. At birth, all of the bone marrows are red. At around the time of puberty, most are red but the amount decreases to 50% at around 18-25 years of age. Despite the change in bone marrow activity, membranous bones and of the arms of and legs remain active throughout life. However, the activity can be changed during pathological conditions. 

Which scenario(s) will result in the activation of inactive bone marrows? 

I. An injury resulting in minor bleeding of the pinky

II. An injury resulting in a rupture of the abdominal aorta

III. A paper cut of the 4th phalange  

Possible Answers:

II and III

I only

I and II

III only

II only

Correct answer:

I only

Explanation:

The activation of inactive bone marrows occur when the increase production of red blood cells is required. An major injury that result massive bleeding will reactive inactive bone marrows. Of the answer choices, a rupture of the abdominal aorta will result in massive internal bleeding. 

Example Question #31 : Circulatory Anatomy

In the heart, blood is oxygen-rich in the __________, and oxygen-poor in the __________.

Possible Answers:

pulmonary arteries . . . pulmonary veins

left ventricle . . . aorta

right atrium . . . left ventricle

left atrium . . . right atrium and right ventricle

superior vena cava . . . right ventricle 

Correct answer:

left atrium . . . right atrium and right ventricle

Explanation:

Blood is oxygenated in the lungs and pumped through the pulmonary veins to the left atrium of the heart. The blood is then pumped to the left ventricle, which pumps the oxygen-rich blood throughout the body. The oxygen-poor blood returns to the heart by entering the right atrium, and remains oxygen poor as it is pumped into the right ventricle and through the pulmonary arteries until it is oxygenated again in the lungs.

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