A & P II Chapter 18 Quiz

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Questions and Answers

How can you visually discern the right and left ventricles of a dissected heart?

Noticing the thickness of the ventricle walls.

Select the correct statement about the heart valves.

The tricuspid valve divides the left atrium from the left ventricle.

The atrioventricular (AV) valves prevent backflow of blood into the atria during ventricular contraction. (correct)

Aortic and pulmonary semilunar valves control the flow of blood into the heart.

The mitral (bicuspid) valve separates the right atrium from the right ventricle.

Select the correct statement about the structure of the heart wall.

The fibrous cardiac skeleton forms the bulk of the heart.

The heart chambers are lined by the endomysium.

The myocardium is the layer of the heart that actually contracts. (correct)

Connective tissue in the heart wall aids in the conduction of the action potential.

What is the explanation for the effect of a calcium channel blocker prescribed to prevent angina?

A drug that inhibits the entry of calcium ions into the cytoplasm of cardiac cells decreases the force of myocardial contractility, thereby decreasing the oxygen demand, relieving the chest pain. Signup and view all the answers

What does hemorrhage with a large loss of blood cause?

A lowering of blood pressure due to change in cardiac output. Signup and view all the answers

What does the P wave of a normal electrocardiogram indicate?

Atrial depolarization. Signup and view all the answers

What might occur if the length of the absolute refractory period in cardiac muscle cells was the same as it is for skeletal muscle cells?

Tetanic contractions might occur, which would stop the heart's pumping action. Signup and view all the answers

When are the atrioventricular (AV) valves closed?

When the ventricles are in systole. Signup and view all the answers

Select the correct statement about the function of myocardial cells.

The presence of gap junctions reflects the activity of the heart's intrinsic conduction system. Signup and view all the answers

Select the correct statement about cardiac output.

A slow heart rate increases end diastolic volume, stroke volume, and force of contraction. Signup and view all the answers

During contraction of heart muscle cells, what happens?

Some calcium enters the cell from the extracellular space and triggers the release of larger amounts of calcium from intracellular stores. Signup and view all the answers

What does isovolumetric contraction refer to?

Refers to the short period during ventricular systole when the ventricles are completely closed chambers. Signup and view all the answers

Study Notes

Heart Anatomy and Function

Right and left ventricles can be differentiated by the thickness of their walls.
Atrioventricular (AV) valves prevent blood backflow into atria during ventricular contraction.
The myocardium is the contractile layer of the heart, while other layers include the endocardium and epicardium.
Cardiac output can be affected by various factors including venous return, stroke volume, and heart rate.

Pharmacology and Heart Response

Calcium channel blockers reduce angina by decreasing myocardial contractility, thereby lowering oxygen demand.
Hemorrhage leading to significant blood loss results in lowered blood pressure due to decreased cardiac output.

Electrical Activity and Cardiac Cycle

The P wave in an electrocardiogram represents atrial depolarization.
The absolute refractory period in cardiac muscle prevents tetanic contractions, ensuring the heart maintains its pumping action.
During isovolumetric contraction, the ventricles are completely closed chambers while blood pressure rises without chamber volume change.

Cardiac Muscle Physiology

Calcium ions enter cardiac cells from extracellular sources and trigger additional calcium release from intracellular stores to facilitate contraction.
Cardiac muscle cells feature gap junctions, allowing synchronized contraction and reflecting the heart's intrinsic conduction system.

Valvular and Chamber Function

AV valves are closed during ventricular systole, preventing backflow into the atria.
A slow heart rate increases end diastolic volume and stroke volume, enhancing cardiac contractility and performance.

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Description

Test your knowledge with flashcards from A & P II Chapter 18, focusing on the anatomy and functions of the heart. This quiz covers important aspects such as the structure of the ventricles and the function of heart valves. Enhance your understanding of cardiovascular anatomy.