BLOOD Dr. B.L. Mtinangi. Department of Physiology HKMU 26 th November, 2015

WHAT IS SO WONDERFUL ABOUT BLOOD?

BLOOD

BLOOD: Is a liquid connective tissue or viscous fluid that: Circulates in a virtually “CLOSED” system of blood vessels Circulates in a virtually “CLOSED” system of blood vessels Has a specific gravity of about – Has a specific gravity of about – Has a Viscosity of about 5 to 6 more than water Has a Viscosity of about 5 to 6 more than water

Components of Blood

BLOOD CONT. Composition of Blood: 45% cells & 55% plasma A: Solid elements (CELLS): 45% 1. Red blood cells-Rbc (Erythrocytes) 4.5 to 5.5 mill/cmm 2. White blood cells- Wbc (Leucocytes) 4000 to 11000/cmm 3. Platelets (Thrombocytes) 200,000 to 400,000/cmm

RED BLOOD CELLS They are red because they contain a protein called hemoglobin that is red in color. Red blood cells are round and thinner in the middle (biconcave) like a balloon that is partly filled with water. This lets them squeeze through tiny blood vessels without breaking.

The Formed Elements: Red Blood Cells (erythrocytes)

The Structure of Rbc

Haemoglobin molecule

Normal & Abnormal Red Cell

BLOOD CONT. B: Fluid (PLASMA) 55% of the whole blood consist: Water (91 to 92%), Gases 0 2, C0 2 & N 2 dissolved in plasma Water (91 to 92%), Gases 0 2, C0 2 & N 2 dissolved in plasma “Solids” (8 to 9%) these are: ORGANIC (7.1 to 8.1%) - Plasma proteins (albumin, globulin, fibrinogen & prothrombin ). “Solids” (8 to 9%) these are: ORGANIC (7.1 to 8.1%) - Plasma proteins (albumin, globulin, fibrinogen & prothrombin ). - Internal secretions (eg antibodies & enzymes) - Internal secretions (eg antibodies & enzymes) - Non Protein Nitroginous substances (urea, neutral fats, CHO, AA etc) - Non Protein Nitroginous substances (urea, neutral fats, CHO, AA etc)

FUNCTIONS OF BLOOD. FUNCTION OF BLOOD: Transport of: Nutrients: blood carries nutrients of digestion from the GIT to tissues. Nutrients: blood carries nutrients of digestion from the GIT to tissues. Dissolved respiratory gases: carries O 2 from lungs to the tissues & CO 2 from tissues to the lungs Dissolved respiratory gases: carries O 2 from lungs to the tissues & CO 2 from tissues to the lungs Carries waste products of metabolism Carries waste products of metabolism Carries other substances like hormones, antibodies, enzymes, drugs etc. Carries other substances like hormones, antibodies, enzymes, drugs etc.

FUNCTIONS OF BLOOD CONT, Defence function through: WBC by phagocytosis through neutrophils monocytes & macrophages WBC by phagocytosis through neutrophils monocytes & macrophages Lymphocytes are involved in immunity Lymphocytes are involved in immunity Platelets & clotting factors prevent blood loss due to bleeding (haemorrhage) after injury Platelets & clotting factors prevent blood loss due to bleeding (haemorrhage) after injury

FUNCTIONS OF BLOOD CONT, Blood is responsible for homeostasis through: Body temperature Body temperature Water concentration of tissues between ICF & ECF Water concentration of tissues between ICF & ECF Acid – Base balance pH through Haemoglobin proteins and bicarbonate Acid – Base balance pH through Haemoglobin proteins and bicarbonate

Thank you for your attention