lab 6 - ECG

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Questions and Answers

What initiates the depolarization of the heart?

Gap Junctions

Sino-atrial Node (correct)

Purkinje Fibers

Atrioventricular Node

The AV Node allows electrical activity from the ventricles to affect the atria.

False

What is the role of Purkinje Fibers in the heart's conduction system?

They are responsible for rapid conduction of the impulse through the ventricular myocardium.

The __________ is a unique property of cardiac muscle allowing it to depolarize without external stimuli.

autorhythmicity Signup and view all the answers

Match the ECG components with their functions:

P-wave = Depolarization from SA Node to atria QT Interval = Time from QRS complex to end of T-wave T-wave = Repolarization of ventricles QRS Complex = Ventricular depolarization Signup and view all the answers

Which structure insulates the ventricles from electrical activity in the atria?

Fibrous Ring Signup and view all the answers

The AV bundle conducts impulses directly from the atria to the lungs.

False Signup and view all the answers

The electrical activity in the heart can be monitored using an __________.

electrocardiogram (ECG) Signup and view all the answers

What is the importance of the fibrous ring in the heart's conduction system?

The fibrous ring insulates the ventricles from electrical activity occurring in the atria, ensuring proper timing of contractions. Signup and view all the answers

How do gap junctions facilitate heart contractions?

Gap junctions allow depolarization to move rapidly from cell to cell within the cardiac muscle, promoting synchronous contractions. Signup and view all the answers

Describe the role of the atrioventricular (AV) node in the heart's conduction system.

The AV node is the only point through which electrical impulses from the atria can pass to the ventricles, allowing for coordinated heart activity. Signup and view all the answers

What does the QT interval on an electrocardiogram (ECG) represent?

The QT interval represents the time from the beginning of the QRS complex to the end of the T-wave, indicating the duration of ventricular depolarization and repolarization. Signup and view all the answers

How do Purkinje fibers contribute to the efficiency of the heart?

Purkinje fibers conduct electrical impulses rapidly throughout the ventricular myocardium, ensuring a swift and coordinated ventricular contraction. Signup and view all the answers

Explain the significance of the P-wave in an ECG.

The P-wave represents the spread of depolarization from the sinoatrial (SA) node to the atria, indicating atrial contraction. Signup and view all the answers

What occurs during the P-Q wave on an ECG?

The P-Q wave indicates a delay in the excitation as the impulse travels through the AV node, allowing the atria to complete their contraction. Signup and view all the answers

How does autorhythmicity affect the heart's function?

Autorhythmicity allows cardiac muscle fibers to self-depolarize at regular intervals without external stimuli, facilitating spontaneous heartbeats. Signup and view all the answers

The __________ is where depolarization of the heart begins and radiates in all directions.

sino-atrial node (SA Node) Signup and view all the answers

The __________ allows the electrical activity from the atria to affect the ventricles.

atrioventricular (AV) node Signup and view all the answers

The __________ connects the atrioventricular node to the ventricles through the bundle branches.

atrioventricular bundle Signup and view all the answers

Electrocardiograms (ECG) detect the __________ and repolarization waves across the heart.

depolarization Signup and view all the answers

During the P-wave, there is a spread of __________ from the SA node to the cardiac muscle of the atria.

depolarization Signup and view all the answers

The __________ is responsible for rapid conduction of electrical impulses to the ventricular myocardium.

Purkinje fibers Signup and view all the answers

The __________ insulates the ventricles from the electrical activity occurring in the atria.

fibrous ring Signup and view all the answers

Gap junctions are housed within __________, allowing depolarization of the heart to move from cell to cell.

intercalated discs Signup and view all the answers

Study Notes

Heart Conduction System

Simultaneous atrial and ventricular contraction is crucial for proper cardiac function.
Cardiac muscle has autorhythmicity, meaning it can self-depolarize and contract without external stimuli.
Sino-atrial (SA) node initiates depolarization, spreading in all directions towards the left side, enabling rapid conduction.
Depolarization spreads through gap junctions between cardiac muscle cells.
Fibrous rings isolate atrial and ventricular electrical activity.
Atrioventricular (AV) node is the only electrical pathway allowing atrial activity to influence ventricles.
Signals from the AV node are then conducted through the AV bundle, right and left bundle branches, and Purkinje fibers.
Purkinje fibers rapidly conduct the signal throughout the ventricular myocardium.

Electrocardiogram (ECG)

ECG measures electrical activity during depolarization and repolarization, detectable at the skin surface.
Body fluids' high conductivity facilitates detection.
Three electrodes (right wrist, left wrist, and left leg) are used for lead I.
Lead I measures the potential difference between two points on the body.
Positive (red) electrode on the left leg, negative (white) on the right wrist.
P wave: atrial depolarization.
PR interval: delay from SA node activity to ventricular excitation.
QRS complex: ventricular depolarization.
T wave: ventricular repolarization.
QT interval: from the start of QRS to end of T, representing ventricular depolarization and repolarization.

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Description

Test your knowledge on the heart conduction system and the electrocardiogram (ECG). This quiz covers the roles of the SA and AV nodes, the conduction pathways, and the significance of ECG in diagnosing cardiac function. Dive into the intricacies of cardiac electrical activity and its importance in heart health.