NURSING CARE RELATED TO THE CARDIOVASCULAR SYSTEM
Section I. ANATOMY AND PHYSIOLOGY
The circulatory system has two major fluid transportation systems, the
cardiovascular (CV) 00system and the lymphatic system.
a. Cardiovascular System. This system, which contains the heart and blood
vessels, is a closed system, transporting blood to all parts of the body. Blood flowing
through the circuit formed by the heart and blood vessels (see Figure 1-1) brings
oxygen, food, and other chemical elements to tissue cells and removes carbon dioxide
and other waste products resulting from cell activity.
b. Lymphatic System. This system, which provides drainage for tissue fluid, is
an auxiliary part of the circulatory system, returning an important amount of tissue fluid
to the blood stream through its own system of lymphatic vessels.
The heart, designed to be a highly efficient pump, is a four-chambered muscular
organ, lying within the chest, with about 2/3 of its mass to the left of the midline. It lies
in the pericardial space in the thoracic cavity between the two lungs. In size and shape,
it resembles a man's closed fist. Its lower point, the apex, lies just above the left
diaphragm. Refer to Figure 1-2 as you continue to read.
a. Heart Layers. The pericardium is a double walled sac enclosing the heart.
The outer fibrous surface gives support, and the inner lining prevents friction as the
heart moves within its protecting jacket. The lining surfaces of the pericardial sac
produce a small amount of pericardial fluid needed for lubrication to facilitate the normal
movements of the heart.
b. Heart Wall. The walls of the heart is composed of three distinct layers an
outer epicardium- which corresponds to the visceral pericardium it protects the heart by
reducing friction, a middle layer the myocardium consist mostly of cardiac muscle tissue
that pumps blood out of the heart chambers, an inner layer endocardium consist of
epithelium and connective tissue that contains many elastic and collagenous fibers.