High School Biology : Understanding Circulatory Function

Study concepts, example questions & explanations for High School Biology

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Example Questions

Example Question #11 : Understanding Circulatory Function

Given that the walls of the heart are not uniform, which of the walls would one expect to be thicker or thinner?

Possible Answers:

The left ventricle wall is thinnest

The inter-ventricular septum is the thickest

The right atrium is thickest

The left ventricle wall is thicker

The right ventricle wall is thicker

Correct answer:

The left ventricle wall is thicker

Explanation:

Blood flows back to the heart through the pulmonary veins after being oxygenated in the lungs and re-enters the heart through the left atrium. The blood then passes into the left ventricle, which pumps an enormous volume of blood via the aorta to the rest of the body. This chamber of the heart is under a lot of pressure since the heart must pump blood through the many miles of vessels and arteries; therefore, the left ventricle wall must be thicker to withstand the force of these contractions. 

Example Question #225 : Organs And Organ Systems

Which of the following chambers of the heart pumps oxygen-rich blood into the body?

Possible Answers:

Vena cava

Left ventricle

Left atrium

Right atrium

Right ventricle

Correct answer:

Left ventricle

Explanation:

The left ventricle pumps blood into the aorta, through which oxygen-rich blood circulates throughout the body. 

Example Question #12 : Understanding Circulatory Function

Which of the following is not a sympathetic effect?

Possible Answers:

Increase in the heart's force of contraction

Increase in urine production

Increased respiratory rate

Increase in heart rate

Pupils dilate

Correct answer:

Increase in urine production

Explanation:

The sympathetic nervous system is a branch of the autonomic nervous system and provides the "fight or flight" response. For this, muscles will need an increased amount of blood, so the heart increases its force of contraction and rate of contraction (heart rate). Additionally, more oxygen needs to be supplied to the muscles, so the respiratory rate also increases. The increase in cardiac output leads to an increase in blood pressure in the sympathetic response. 

During the sympathetic response, blood flow is shunted from other organs and sent to the heart and muscles instead. Therefore, digestion and urine production is decreased. Less blood to the kidneys means less urine gets produced.

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