Heart Physiology: The Cardiac Cycle

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During diastole in the cardiac cycle, what happens?

Ventricles contract forcing blood up and out of the heart arteries
AV valves shut
Atria contract simultaneously to complete the filling of ventricles
Atria and ventricles fill with blood (correct)

Where is the sinoatrial (SA) node located?

In the wall of the right atrium (correct)
In the right and left bundle branches
In the interventricular septum
In the junction of the R & L atria

What is the function of the atrioventricular (AV) node in the heart's conduction system?

To fill the ventricles with blood
To contract simultaneously with atria
To regulate heart wall contractions via electrical impulses (correct)
To cause AV valves to shut

Which part of the heart acts as a 'pacemaker' due to its role in generating electrical impulses?

Sinoatrial (SA) node (C) Signup and view all the answers

What triggers the semilunar valves to shut during the cardiac cycle?

Backflow in the aorta & pulmonary arteries (B) Signup and view all the answers

What is the main role of the bundle branches in the heart's conduction system?

To carry nerve impulses affecting contractions (C) Signup and view all the answers

Which component of the heart's electrical conduction system is responsible for depolarizing the atria?

SA node (D) Signup and view all the answers

What is the main purpose of an electrocardiogram (ECG or EKG)?

Recording the electrical changes in the myocardium during a cardiac cycle (C) Signup and view all the answers

Which condition results in an irregular and often rapid heart rate, leading to decreased blood flow?

Fibrillation (C) Signup and view all the answers

What is the formula for cardiac output?

(Heart rate) x (Stroke volume) (B) Signup and view all the answers

Which of the following conditions can lead to abnormalities or damage to the heart's structure?

None of the above (D) Signup and view all the answers

What is the term used to describe a heart rate of more than 100 beats per minute?

Tachycardia (C) Signup and view all the answers

What is the formula for calculating cardiac output?

(Heart rate) x (Stroke volume) (A) Signup and view all the answers

How is cardiac output regulated in the body?

By changing the heart rate (C) Signup and view all the answers

What factors can lead to an increase in heart rate?

High blood pressure (A) Signup and view all the answers

How does digitalis work in congestive heart failure?

It provides a slow and steady beat (B) Signup and view all the answers

What is the role of the parasympathetic nervous system in regulating heart rate?

Decreases heart rate (D) Signup and view all the answers

How often does the entire blood supply pass through the body?

Every 60 seconds (C) Signup and view all the answers

Diastole

The phase of the cardiac cycle where the heart chambers fill with blood.

Location of SA node

The sinoatrial (SA) node is located in the upper right chamber of the heart, the right atrium.

AV node function

The atrioventricular (AV) node functions as a gatekeeper, ensuring coordinated contraction of the heart chambers by allowing electrical impulses to pass through only after the atria have contracted.

Heart Pacemaker

The sinoatrial (SA) node acts as the heart's natural pacemaker, generating electrical impulses that trigger the heartbeat.