Chapter 21, Problem 1RFT

Match each numbered item with the most closely related lettered item.

cardiac muscle cells.............................

Summary Introduction

To review:

Match the term cardiac muscle cells with the most closely related descriptions given below:

Vein to the left atrium

Covers outer surface of the heart

Supplies blood to heart muscle

Lines inner surface of fibrous pericardium

Slow heart rate

Functional syncytium

Muscular wall of the heart

Relaxation phase of the cardiac cycle

Vein to the right atrium

Contraction phase of the cardiac cycle

Introduction:

The heart’s wall is known as myocardium, which is made up of cardiac muscle cells. The cardiac muscle cells are made up of myofibrils, which consists of long chains of sarcomeres. These cells show striates similar to those shown in the skeletal muscle cells.

Explanation of Solution

A true syncytium possesses multiple nuclei, like the cells of the skeletal tissues. On the other hand, the cardiac muscles do not consist of multinucleated cells. Instead, they show functional syncytium as they are separated by the gap junctions and here when one cell gets contracted the contraction triggers the contraction of other cells and likewise the contraction carries by the whole myocardium. This property of the cardiac cells allows rapid contraction of the heart muscles without getting fatigued.

Conclusion

Therefore, it can be concluded that the cardiac muscle cells can be correctly matched with option (f) functional syncytium.