Anatomy & Physiology Cardiac #2

Question

Which statement is correct regarding the heart, or cardiac cycle?

Answers

  1. “The heart cycle consists of one phase.”
    • Rationale:

      There are two phases of the cardiac cycle, not one phase; therefore, this statement is incorrect.

  2. “The heart cycle consists of two phases.”
    • Rationale:

      This statement is correct in regard to the cardiac cycle. It consists of two phases, diastole (i.e., relaxation) and systole (i.e., contraction).

  3. “The heart cycle consists of three phases.”
    • Rationale:

      There are two phases of the cardiac cycle, not one phase; therefore, this statement is incorrect.

  4. “The heart cycle consists of four phases.”
    • Rationale:

      There are two phases of the cardiac cycle, not four phases; therefore, this statement is incorrect.

Overview

The cardiac (i.e., heart) cycle is defined as the sequence of events in the heart muscle from the beginning of one beat to the beginning of the next beat.

Explanation

Learning Outcomes

The heart cycle is a sequence of alternating contraction and relaxation of the atria and ventricles within the cardiac muscle. The primary function of this process is to pump blood throughout the body. This cycle has two phases, diastole and systole. Diastole is defined as the relaxation phase of the cardiac cycle while systole is the contraction phase of this same cycle.

Test Taking Tip

Remember that a heart beat cycle is the “lub dub” you hear when auscultating the heart sounds. Use this information to help you choose the correct answer

Video Rationale