Cardiovascular System

Cardiovascular System

Introduction

The cardiovascular system comprises of the heart, as its principal component, and it has relating intricate conduits, including capillaries, arteries, and veins that traverse the whole human body. The chief function of the cardiovascular system is to carry blood, which contains oxygen, essential nutrients, wastes, and other functional cells, facilitating in maintaining homeostasis, as well as, the basic function of cells and organs (Buddiga, 2012).

The heart is an anatomical pump, maintaining a balance between the cardiac output and venous return. Cardiac output (CO) refers to the amount of blood pumped by the heart per minute. It varies according to the demands of the body. Cardiac cycle refers to the series of events that occur in one complete heartbeat. Each cycle consists of a ventricular systoles and diastole and occurs about 72 times/minute. The duration of a complete cardiac cycle is 0.8sec. The heart sounds heard results from the closing of heart valves. Abnormal heart sounds, occurring due to valve abnormalities or incompetency, are known as murmurs (Buddiga, 2012).

Discussion

Gross Anatomy of the Cardiovascular system

The heart

The heart is a muscular organ, which weighs about 250-350 grams. It lies obliquely in the middle mediastinum. It comprises of four chambers, two atria and two ventricles. The left side, atrium and ventricle, supplies blood to the systemic circulation; and, the right side supplies the pulmonary circulation. The chambers are separated by atrio-ventricular valves (AV valves), comprising of mitral and tricuspid. The valvular system inside the heart enforces the unidirectional blood flow (Gray, 1918).

The cardiac muscle cells are unique. These are specialized, striated, branching cells, with one nucleus and multiple myofibrils. Each cardiac cells links with its adjacent via intercalated discs containing gap junctions and desmosomes. This allows the myocardium to function as a single unit as electrical coupling action occurs by gap junctions. Furthermore, there are abundant mitochondria, existing in the cardiac cells, for aerobic respiration by generating ATP (Gray, 1918).

Anatomy of the circulatory system

The systemic circulation originates from the left side of the heart. It functions when oxygen-rich blood enters the left atrium from the lungs. The blood then flows into the left ventricle through the mitral valve, from where it is pumped to the whole body via the aortic valve. The right side comprises the pulmonary circulation and primarily functions for gas exchange. Venous blood reaches the left atrium vie three main veins: SVC, IVC, and coronary ...