BLOOD FLOW

Blood is a bodily fluid that delivers necessary substances such as nutrients and oxygen to the cells and transport metabolic waste materials away from cells.

It is composed of blood cells suspended in blood plasma. Plasma consists of 55% of blood fluid and it contains mostly water up to 92%. It carries proteins, glucose, minerals, hormones, carbon dioxide and blood cells.

Albumin is the main protein in plasma and it maintains blood pressure. The blood cells are mainly red blood cells, white blood cells and platelets. The red cells contain hemoglobin, an iron containing protein. It helps in transport of oxygen binding to respiratory gas and increases solubility in the blood.

Vertebrate blood has bright red color when it is oxygenated and dark red when it is deoxygenated. Blood is circulated around the body through blood vessels by pumping action of the heart.

Red blood cells contain blood’s hemoglobin and distribute oxygen. White blood cells form part of body’s immune system. They destroy and remove old cells, cellular debris, infectious agents and foreign substances. Platelets take part in blood clotting. 

Plasma occupies 55% of blood volume. Its normal color is yellow. It contains 92% water and 8% blood plasma proteins. It circulates dissolved nutrients such as glucose, amino acids and fatty acids. It removes waste products such as carbon dioxide, urea and lactic acid.

Diagram of a myocardial infarction (2) of the anterior wall of the heart after blockage (1) of a branch of the left coronary artery (LCA). In the diagram, RCA is the right coronary artery.

Cardiovascular system: Blood is pumped from strong left ventricles through arteries to peripheral tissues. Then it returns to right atrium through veins. It then enters the right ventricles and is pumped through pulmonary artery to the lungs. Then it returns to left atrium by pulmonary veins. Then blood enters the left ventricles to be circulated again.

Heart plays a vital role in blood circulation for the entire body. The heart muscles must be healthy then only they can pump the blood to and fro. Regular blood supply to heart muscles becomes essential.