How it Works
Try Naxlex NCLEX-RN (Free-Trial)

Match the structure to its description.

Description

Structure

A cluster of cells located in the interatrial septum that delays the electrical signal before it passes to the ventricles.

The pacemaker of the heart, located in the right atrium, responsible for initiating the heartbeat.

The valve located between the right atrium and right ventricle.

The layer of the pericardium that covers the heart directly, also known as the epicardium.

Blood vessels carrying oxygenated blood from the lungs to the left atrium.

Answer and Explanation

The Correct Answer is {"dropdown-group-1":"D","dropdown-group-2":"E","dropdown-group-3":"B","dropdown-group-4":"A","dropdown-group-5":"C"}

Correct answer:

  • A cluster of cells located in the interatrial septum that delays the electrical signal before it passes to the ventricles: Atrioventricular node
  • The pacemaker of the heart, located in the right atrium, responsible for initiating the heartbeat: Sinoatrial node
  • The valve located between the right atrium and right ventricle: Tricuspid valve
  • The layer of the pericardium that covers the heart directly, also known as the epicardium: Visceral pericardium
  • Blood vessels carrying oxygenated blood from the lungs to the left atrium: Pulmonary veins

 

• Atrioventricular node: The AV node is located in the interatrial septum and functions to delay the electrical impulse received from the SA node. This delay allows the atria to contract and complete ventricular filling before ventricular contraction. Its position and timing role are crucial for coordinated cardiac conduction.

• Sinoatrial node: The SA node, located in the right atrium near the superior vena cava, acts as the heart’s natural pacemaker. It generates electrical impulses that initiate each heartbeat, setting the rhythm for the entire heart. Proper SA node function is essential for synchronized atrial and ventricular activity.

• Tricuspid valve: The tricuspid valve sits between the right atrium and right ventricle, preventing backflow of blood during ventricular contraction. Its three leaflets open during diastole to allow atrial emptying into the ventricle. Proper valve function maintains unidirectional blood flow and cardiac efficiency.

• Visceral pericardium: Also called the epicardium, this layer of the pericardium lies directly on the heart surface. It provides protection, reduces friction during heartbeats, and contains blood vessels supplying the myocardium. Its anatomical position distinguishes it from the parietal pericardium.

• Pulmonary veins: Pulmonary veins carry oxygen-rich blood from the lungs to the left atrium. They are unique among veins as they transport oxygenated rather than deoxygenated blood. Their flow ensures that systemic circulation receives oxygenated blood.


Get 100+ Naxlex Exit Exams for $79 Try Naxlex NCLEX-RN (14 Day Free-Trial)

Naxlex Comprehensive Predictor Exams

Free Nursing Study Resources

Related Questions

Correct Answer is A

Explanation

A. It marks the boundary of the sarcomere and anchors thin filaments: The Z-line, also called the Z-disc, is a dense protein structure that defines the lateral boundary of each sarcomere in cardiac muscle. It serves as the anchoring site for actin (thin) filaments and plays a critical role in transmitting the force generated during sarcomere shortening across the myocardial tissue, contributing to coordinated contraction.

B. It shortens during contraction to generate force: The Z-line itself does not shorten; rather, the sarcomere shortens as thin and thick filaments slide past each other. The Z-lines move closer together during contraction, but they act as structural anchors, not active generators of force.

C. It houses mitochondria for ATP production: Mitochondria are located in the cytoplasm between myofibrils, not within the Z-line. They provide ATP necessary for cross-bridge cycling, but their presence is independent of the Z-line structure.

D. It serves as a storage site for calcium ions: Calcium ions are primarily stored in the sarcoplasmic reticulum and released during excitation-contraction coupling. The Z-line does not function as a calcium reservoir; its role is structural and mechanical within the sarcomere.

Correct Answer is B

Explanation

Correct answer: False

The relative refractory period occurs during the latter part of the cardiac action potential, specifically during phase 3 (repolarization) of ventricular muscle cells. During this period, the myocardial cell has partially repolarized but has not yet fully returned to its resting membrane potential. While the cell can respond to a stronger-than-normal stimulus, normal stimuli will not trigger a contraction. Anatomically, this period applies to cardiac myocytes throughout the atria and ventricles, ensuring coordinated contractions while preventing premature or tetanic contractions, which could compromise effective cardiac output.

Whether you are a student looking to ace your exams or a practicing nurse seeking to enhance your expertise , our nursing education contents will empower you with the confidence and competence to make a difference in the lives of patients and become a respected leader in the healthcare field.

Visit Naxlex, invest in your future and unlock endless possibilities with our unparalleled nursing education contents today

Register