Human Anatomy and Physiology : Circulatory and Respiratory Physiology

Study concepts, example questions & explanations for Human Anatomy and Physiology

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Example Questions

Example Question #31 : Circulatory Physiology

Which of the following factors influence cardiac output?

Possible Answers:

Heart rate

All of these factors influence cardiac output

Afterload

Preload

Correct answer:

All of these factors influence cardiac output

Explanation:

Cardiac output is defined as stroke volume times heart rate. Stroke volume (the volume of blood pumped out each heart beat) is influenced by preload (the volume of blood in the ventricles at the end of diastole) and afterload (the pressure that the heart must pump against to eject blood). Therefore, by definition, heart rate influences cardiac output, and so do preload and afterload, due to their influence on stroke volume. 

Example Question #501 : Systems Physiology

Which area does not contain oxygen-rich blood?

Possible Answers:

Left atrium

Aorta

Left ventricle

Pulmonary artery

Brachiocephalic trunk

Correct answer:

Pulmonary artery

Explanation:

The pulmonary artery is the vessel that leaves the right ventricle and enters into the lung tissue to undergo oxygen exchange. The pulmonary artery is known to be the only artery in the body that does not carry oxygen-rich blood. 

An artery is defined as a vessel that leaves the heart and a vein is a vessel that returns to the heart. The pulmonary artery is the vessel carrying deoxygenated blood away from the heart. 

Example Question #502 : Systems Physiology

Which of the following represents a reason why a "p-wave" of an ECG would be increased in duration?

Possible Answers:

Hyperkalemia

Enlarged ventricle

Hypercalcemia

Ventricular hypertrophy

Enlarged atrium

Correct answer:

Enlarged atrium

Explanation:

A "p-wave" in an ECG correlated to depolarization and contraction of the atria of the heart. The duration of the "p-wave" is associated with how low it takes an electrical signal to transfer across an atrium from the sinoatrial node to the atrioventricular node. Therefore, a prolonged "p-wave" can be commonly associated with an enlarged atrium because the electrical signal has further to travel across a dilated chamber.

Example Question #31 : Help With Heart Physiology

The heart contains what type of adrenergic receptor to respond to epinephrine from the sympathetic nervous system?

Possible Answers:

Alpha 2 adrenergic

Alpha 1 adrenergic

Beta 2 adrenergic

Beta 1 adrenergic

Muscarinic cholinergic

Correct answer:

Beta 1 adrenergic

Explanation:

Beta 1 receptors are the adrenergic receptor on the heart muscle that are responsive to epinephrine and norepinephrine released by the sympathetic nervous system.

Beta 2 adrenergic receptors are primarily located within the pulmonary tissue to cause bronchodilation during a sympathetic response.

Muscarinic cholinergic receptors are present on many tissue types, but are the receptors for acetylcholine rather than epinephrine or norepinephrine.

Alpha 1 adrenergic receptors are present on peripheral blood vessels and respond primarily to norepinephrine to cause vasoconstriction during a sympathetic response.

Alpha 2 adrenergic receptors are special receptors present on the preganglionic sympathetic neuron that help to depress a sympathetic response through negative feedback inhibition.

Example Question #31 : Circulatory And Lymphatic Physiology

Which valve allows blood to enter the right ventricle from the right atrium and prevents backflow of blood?

Possible Answers:

Bicuspid valve 

Tricuspid valve

Pectinate valve

Semilunar valve

Correct answer:

Tricuspid valve

Explanation:

The tricuspid (atrioventricular) valve separates the right atrium from the right ventricle and prevents back-flow during systole (heart contraction). The path of blood in the heart goes as follows: right atrium, tricuspid valve, right ventricle, pulmonary valve, pulmonary artery, lungs, pulmonary vein, left atrium, mitral valve, left ventricle, aortic valve, aorta, systemic circulation.

Example Question #32 : Circulatory Physiology

Which limb lead will give the best view of atrial depolarization?

Possible Answers:

Augmented vector left (aVL)

Lead III

Lead I

Lead II

Augmented vector right (aVR)

Correct answer:

Lead II

Explanation:

Lead II is the limb lead that will show the best view of atrial depolarization. Remember, atrial depolarization starts at the sinoatrial node in the right atrium and spreads through the right and left atria. If you were to draw this on a heart, the net vector would be down (inferiorly) and to the left side of the heart. Also remember, lead II is the lead configuration that runs from the right arm to the left leg. aVR would show a good view of atrial depolarization (although it would be a negative deflection), but it is an augmented lead, not a limb lead. aVL is also an augmented lead.

Example Question #32 : Circulatory And Lymphatic Physiology

What is the primary factor responsible for changes in resistance in blood vessels?

Possible Answers:

pH

Viscosity of the blood

Hematocrit

Length of the blood vessels

Diameter of the blood vessels

Correct answer:

Diameter of the blood vessels

Explanation:

The diameter of the vessels is the primary determinant of resistance. Our three factors affecting resistance of a vessel are length, viscosity, and diameter. Length of the vessel and viscosity of the blood are relatively constant, so that just leaves diameter. Hematocrit is percentage of blood as red blood cells and would represent viscosity.

Example Question #31 : Circulatory And Lymphatic Physiology

Cardiac output increases with the all but which of the following. 

Possible Answers:

decreasing end systolic volume

increasing stroke volume

increasing ejection fraction

decrease ejection fraction

Correct answer:

decrease ejection fraction

Explanation:

Cardiac output is directly proportion to both heart rate and stroke volume. Decreasing ejection fraction decreases stroke volume, which would decrease cardiac output, not increase it.

Example Question #1 : Help With Pulmonary Circuit Physiology

The pulmonary veins carry oxygen-rich blood from the __________ to the __________

Possible Answers:

lungs . . . left ventricle 

left atrium . . . lungs 

right ventricle . . . lungs 

lungs . . . left atrium 

lungs . . . right atrium 

Correct answer:

lungs . . . left atrium 

Explanation:

The pulmonary veins carry oxygenated blood form the lungs to the left atrium of the heart. The pulmonary arteries carry deoxygenated blood from the right ventricle to the lungs. 

Example Question #1261 : Human Anatomy And Physiology

What is the name of the blood vessel that carries newly oxygenated blood from the lung back to the heart?

Possible Answers:

Pulmonary trunk

Aorta

Pulmonary vein

Pulmonary artery

Superior vena cava

Correct answer:

Pulmonary vein

Explanation:

When blood needs to leave the heart to become oxygenated, it leaves the right ventricle through the pulmonary trunk, which then splits into the right and left pulmonary arteries. This blood goes to the lungs, becomes oxygenated, and comes back to the heart via the right and left pulmonary veins, which empty into the left atrium. The newly oxygenated blood travels through the left atrium and ventricle of the heart before it exits through the aorta to deliver freshly oxygenated blood to the rest of the body.

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