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Which wave in an electrocardiogram represents depolarization of the atria? a- R

ID: 3513130 • Letter: W

Question

Which wave in an electrocardiogram represents depolarization of the atria?

a- R wave

B- T wave

C- S wave

D- P wave

E- Q wave

Which statement is CORRECT regarding phase 1 of membrane action potential of the contraction or cardiomyocytes cells in the heart?

A- The voltage-gated K+ channels are open

B- The L-type voltage-gated Ca++ channels are open

C- The transient K+ channels are open

D- The membrane potential does not change

This is a network of specialized cardiac muscle fibers that provide a path for each cycle of cardiac excitation to progress through the heart.

A- Systemic circuit

B- Intercalated discs

C- Cardiovascular center

D- Cardiac conduction system

E- Pulmonary circuit

Which of the following structures allows blood to pass from the right atrium to the right ventricle?

A- Bicuspid valve

B— Interventricular septum

C- Tricuspid valve

D- Mitral valve

E- Ascending aorta

Contraction of the ventricles of the heart leads to blood moving directly_________

A- Into arteries.

B- Into capillaries.

C- Into veins.

D- Through an atrioventricular valve.

Blood leaving the left ventricle passes through which of the following structures?

A- Right atrium

B- Bicuspid valve

C- Aortic semilunar valve

D- Pulmonary semilunar valve

In which period during a cardiac cycle contraction of a chamber occurs and pressure within the chamber rises?

A- filling

B- systole

C- repolarization

D-diastole

E- fibrillation

Which of the following chambers of the heart is surrounded by the thickest layer of myocardium?

A- right atrium

B- left atrium

C- right ventricle

D- left ventricle

Which structure in the heart initiates action potentials that stimulate contraction of the heart at a constant rate ?

A- Cardiac accelerator nerves

B- Atrioventricular node

C- Cardiovascular center

D- Sinoatrial node

E- Bundle of His

Which layer of the heart wall consists of cardiac muscle tissue?

A- Epicardium

B- Pericardium

C- Myocardium

D- Endocardium

Explanation / Answer

Answer: P wave.

2. Which statement is CORRECT regarding phase 1 of membrane action potential of the contraction or cardiomyocytes cells in the heart?

Answer: B- The L-type voltage-gated Ca++ channels are open

3. This is a network of specialized cardiac muscle fibers that provide a path for each cycle of cardiac excitation to progress through the heart.

Answer: Intercalated discs.

4. Which of the following structures allows blood to pass from the right atrium to the right ventricle?

Answer: Tricuspid valve.

5. Contraction of the ventricles of the heart leads to blood moving directly-----

Answer: Into arteries.

From ventricles, the blood is transported to different parts of body through arteries.