Chapter: 11th 12th std standard Class Nursing Health Care Hospital Hygiene Higher secondary school College Notes
Functions of the Heart and Cardiovascular system
FUNCTIONS OF THE HEART
1.
Heart possesses 4 chambers (2 atria and 2
ventricles) Blood enters the left atrium (LA) and left ventricle (LV) at a
pressure near zero. The left ventricle pumps the blood into systemic
circulation via the main distributing artery the aorta. Aorta divides into
arteries which undergo successive divisions forming arterioles. These subdivide
and lead to capillaries. Capillaries distribute the blood to the veins, which
return the blood to the right atrium (RA) and right ventricle (RV) via great
veins (inferior and superior vena cava).
2.
'RA' and 'RV' receive blood which has returned
from the tissues via the veins. The 'RV' pumps the blood into pulmonary
circulation via the pulmonary artery. The aorta divides into arterioles and
leads to pulmonary capillaries. Pulmonary capillaries facilitate exchange of
gases across them. The oxygenated blood is then collected from the pulmonary
capillaries by pulmonary venules and veins and transported to the 'LA' and
'LV'.
3.
Heart provides the pressure for circulation.
Functions of
cardiovascular system
1.
Distribution of metabolites and oxygen to all
the body cells.
2.
Collection of waste products and CO2
from different body cells and carry them to excretory organs.
3.
Thermoregulation - carrying of heat from active
metabolic sites (where heat is generated) to body surface where it is
dissipated. Blood flow through skin varies to enhance or decrease the heat loss
to the environment.
4.
Distribution of hormones to the target tissues.
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