Cardiovascular System

What does the sympathetic nervous system do to heart rate?

• Increases

• Decreases

• Keeps it the same

Answer explanation

The sympathetic nervous system activates the body's fight-or-flight response, which leads to an increase in heart rate to supply more oxygen and nutrients to muscles, thus the correct answer is 'Increases'.

What does the parasympathetic nervous system do to heart rate?

• Decreases

• Increases

• Keeps it the same

Answer explanation

The parasympathetic nervous system decreases heart rate by releasing acetylcholine, which acts on the heart's pacemaker cells, leading to a reduction in the rate of contraction. Therefore, the correct answer is 'Decreases'.

Which of the following blood vessels carries oxygenated blood away from the heart?

• Artery

• Capillary

• Venule

• Vein

Answer explanation

The artery is the blood vessel that carries oxygenated blood away from the heart to the tissues. In contrast, veins carry deoxygenated blood back to the heart, while capillaries and venules are involved in the exchange of gases.

The pulmonary artery carries

• Deoxygenated blood to the lungs

• Oxygenated blood to the lungs

• Oxygenated blood to the body

• Deoxygenated blood to the body

Answer explanation

The pulmonary artery is unique as it carries deoxygenated blood from the heart to the lungs for oxygenation, making 'Deoxygenated blood to the lungs' the correct choice.

The cardiac conduction cycle is initiated by the

• SA node

• AV node

• Bundle of His

• Purkinje fibers

Answer explanation

The cardiac conduction cycle is initiated by the SA node, which acts as the primary pacemaker of the heart, generating electrical impulses that trigger heartbeats.

Which of the following factors affects the cardiac conduction cycle?

• All of the following

• Hormones

• Electrolyte levels

• Temperature

Answer explanation

All of the listed factors—hormones, electrolyte levels, and temperature—can influence the cardiac conduction cycle by affecting heart rate and rhythm, making 'All of the following' the correct answer.

Blood pressure is highest in the

• Arteries

• Veins

• Capillaries

• Venules

Answer explanation

Blood pressure is highest in the arteries because they are closest to the heart, where blood is pumped with the greatest force. This pressure decreases as blood moves through the veins and capillaries.

During exercise, blood is redistributed to

• Muscles

• Digestive system

• Skin

Answer explanation

During exercise, blood is primarily redirected to the muscles to meet their increased demand for oxygen and nutrients, enhancing performance. The digestive system receives less blood flow as it is not a priority during physical activity.

Which of the following vessels carries oxygenated blood back to the heart?

• Pulmonary vein

• Pulmonary artery

• Aorta

• Vena cava

Answer explanation

The pulmonary vein is the vessel that carries oxygenated blood from the lungs back to the heart. In contrast, the pulmonary artery carries deoxygenated blood to the lungs, while the aorta and vena cava deal with systemic circulation.

The exchange of nutrients and waste products between blood and tissues occurs primarily in

• Capillaries

• Arteries

• Veins

• Venules

Answer explanation

The exchange of nutrients and waste products primarily occurs in capillaries, which are the smallest blood vessels. They have thin walls that allow for efficient diffusion between blood and surrounding tissues.