Question

describe the location of the cardiovascular system organs using directional terms

Answer 1

Cardiovascular system is the transport system of the body, through which the nutrients are conveyed to places where these are utilized, and the metabolites (waste products) are conveyed to appropriate places from where these are expelled.Cardiovascular system includes heart and blood vessels .

Cardiovascular system is a closed system of tubes made up of the following parts

1. Heart: It is a four-chambered muscular organ which pumps blood to various parts of the body. Each half of the heart has a receiving chamber called atrium, and a pumping chamber called ventricle.
2. Arteries: These are distributing channels which carry blood away from the heart.
(a) They branch like trees on their way to different parts of the body.
(b) The large arteries are rich in elastic tissue, but as branching progresses there is an ever-increasing amount of smooth muscle in their walls.
(c) The minute branches which are just visible to naked eye are called arterioles.
(d) Angeion is a Greek word, meaning a vessel (blood vessel or lymph vessel). Its word derivatives are angiology, angiography, haemangioma, and thromboangitis obliterans.
3. Veins: These are draining channels which carry blood from different parts of the body back to the heart.
(a) Like rivers, the veins are formed by tributaries.
(b) The small veins (venules) join together to form larger veins, which in turn unite to form great veins called venae cavae

Capillaries: These are networks of microscopic vessels which connect arterioles with the venules.
• These come in intimate contact with the tissues for a free exchange of nutrients and metabolites across their walls between the blood and the tissue fluid.
• The metabolites are partly drained by the capillaries and partly by lymphatics.
• Capillaries are replaced by sinusoids in certain organs, like liver and spleen.

Functionally, the blood vessels can be classified into the following five groups.
(a) Distributing vessels, including arteries;
(b) Resistance vessels, including arterioles and precapillary sphincters;
(c) Exchange vessels, including capillaries, sinusoids, and postcapillary venules;
(d) Reservoir (capacitance) vessels, including larger venules and veins; and

(e) Shunts, including various types of anastomoses.

HEART

Heart is a vital organ, pumping blood to the entire body .It is a conical hollow muscular organ situated in the middle mediastinum. It is enclosed within the pericardium . The human heart has four chambers. These are the right
and left atria and the right and left ventricles.

The heart has
. An apex directed downwards, forwards and to the left,
. A base (posterior surface) directedbackwards; and
. Anterior/sternocostal
. Inferior and
. Left lateral surfaces

The surfaces are demarcated by upper, inferior, right and left borders.

APEX OF HEART

Apex of the heart is formed entirely by the left ventricle. It is directed downwards, forwards and to the left and is overlapped by the anterior border of the left lung. It is situated in the left fifth intercostal space 9 cm lateral to the midstemal line just medial to the midclavicular line.

In children below 2 years, apex is situated in the left fourth intercostal space in midclavicular line.

A BASE OF HEART

The base of the heart is also called its posterior surface. It is formed mainly by the left atrium and by a small part of the right atrium. In relation to the base one can see the openings of four pulmonary veins which open into the left atrium; and of the superior and inferior venae cavae which open into the right atrium. It is related to thoracic five to thoracic eight vertebrae in the lying posture, and decends by one vertebra in the erect posture. It is separated from the vertebral column by the pericardium, the right pulmonary veins, the oesophagus and the aorta.

SURFACES OF HEART
The anterior or sternocostal surface is formed mainly by the right atrium and right ventricle, and partly by the left ventricle and left auricle. The left atrium is not seen on the anterior surface as it is covered by the aorta and pulmonary trunk. Most of the sternocostal surface is covered by the lungs, but a part of it that lies behind the cardiac notch of the left lung is uncovered .

The inferior or diaphragmatic surface rests on the central tendon of the diaphragm. It is formed in its left two-thirds by the left ventricle, and in its right one third by the right ventricle. It is traversed by the posterior interventricular groove, and is directed downwards and slightly backwards.

The left surface is formed mostly by the left ventricle, and at the upper end by the left auricle. In its upper part, the surface is crossed by the coronary sulcus. It is related to the left phrenic nerve, the left pericardiacophrenic vessels, and the pericardium