FUNCTIONS OF BLOOD
1. NUTRITIVE FUNCTION
Nutritive substances like glucose, amino acids, lipids and vitamins derived from digested food are absorbed from gastrointestinal tract and carried by blood to different parts of the body for growth and production of energy.
2. RESPIRATORY FUNCTION
Transport of respiratory gases is done by the blood. It carries oxygen from alveoli of lungs to different tissues and carbon dioxide from tissues to alveoli.
3. EXCRETORY FUNCTION
Waste products formed in the tissues during various metabolic activities are removed by blood and carried to the excretory organs like kidney, skin, liver, etc. for excretion.
4. TRANSPORT OF HORMONES AND ENZYMES
Hormones which are secreted by ductless (endocrine) glands are released directly into the blood. The blood transports these hormones to their target organs/tissues.
Blood also transports enzymes.
5. REGULATION OF WATER BALANCE
Water content of the blood is freely interchangeable with interstitial fluid. This helps in the regulation of water content of the body.
6. REGULATION OF ACID-BASE BALANCE
Plasma proteins and hemoglobin act as buffers and help in the regulation of acid-base balance .
7. REGULATION OF BODY TEMPERATURE
Because of the high specific heat of blood, it is responsible for maintaining the thermoregulatory mechanism in the body, i.e. the balance between heat loss and heat gain in the body.
8. STORAGE FUNCTION
Water and some important substances like proteins, glucose, sodium and potassium are constantly required by the tissues. Blood serves as a readymade source for these substances. And, these substances are taken
from blood during the conditions like starvation, fluid loss, electrolyte loss, etc.
9. DEFENSIVE FUNCTION
Blood plays an important role in the defense of the body. The white blood cells are responsible for this function. Neutrophils and monocytes engulf the bacteria by phagocytosis. Lymphocytes are involved in
development of immunity. Eosinophils are responsible for detoxification, disintegration and removal of foreign proteins