Blood blood connective tissue in fluid form

Functions of plasma proteins

• Coagulation of blood – Fibrinogen to fibrin
• Defense mechanism of blood – Immunoglobulins
• Transport mechanism – α Albumin, β globulin transport hormones, gases, enzymes, etc.
• Maintenance of osmotic pressure in blood
• Acid-base balance
• Provides viscosity to blood
• Provides suspension stability of RBC
• Reserve proteins

Formed Elements of Blood

• Red blood cells (R.B.C.)
• White blood cells (W.B.C.)
• granular leukocytes
• neutrophils
• eosinophils
• basophils
• agranular leukocytes
• lymphocytes - T cells, B cells, natural killer cells (N.K.C)
• monocytes
• Platelets (special cell fragments)

Functions of RBC

• Transport oxygen from lungs to the tissues (oxyhemoglobin).
• Transport carbon-di-oxide from tissues to lungs (carboxyhemoglobin)
• Hemoglobin acts as a buffer and regulates the hydrogen ion concentration (acid base balance)
• Carry the blood group antigens and Rh factor

Functions of neutrophils

• First line of defence against invading micro-organisms.
• Powerful and effective killer machine – contains enzymes like protease, elastase, metalloproteinase, NADPH oxidase; antibody like substances called defensins.
• Defensins – antimicrobial peptides active against bacteria and fungi.
• 3.Secrete Platelet Aggregation Factor (PAF) – accelerates the aggregation of platelet during injury to the blood vessels

Functions of eosinophils

• Secrete lethal substances at the time of exposure to foreign proteins/parasites
• Eosinophill peroxidase – detroy worms, bacteria and tumor cells.
• Major basic protein – damage parasites
• Eosinophill cationic protein (ECP)- destroys helminths.
• Eosinophill derived neurotoxin – destroys nerve fibres (myelinated nerve fibres)

Functions of basophils

• Basophill granules release some important substances like –
• Histamine – Acute hypersensitivity reaction- vascular changes, increase capillary permeability
• Heparin – prevents intravascular blood clotting
• Hyaluronic acid – necessary for deposition of ground substances in basement membrane
• Proteases – exaggerate inflammation
• Basophill have IgE receptor – hypersensitivity reaction

Functions of Platelets

• Blood clotting
• Clot retraction
• Defence mechanism
• Homeostasis
• Repair and rupture of blood vessel

Gas transport

• Continuous interchange of CO2 and O2 between lungs and tissues.
• Oxygen –
• major e- acceptor
• indispensable for ATP production.
• CO2
• major by product of energy metabolism

pH maintenance

• Oxygen release helps to maintain pH in tissues
• Lungs:
• HHb + O2 = HbO2 + H+
• Tissues:
• CO2 forms proton and bicarbonate
• Proton is bound to Hb, when O2 is released
• Bicarbonate leaves RBC
• Cl- / HCO3- interchange - Hamburger effect

Hb

• Higher ability of Hb to release O2 but lower ability to bind O2 - Right shift
• Useful at site of O2 release (tissues)
• higher temperature
• higher 2,3 BPG level
• lower pH (Bohr effect)

CO2 transport

• Bicarbonate formation within RBC and Cl interchange
• CO2 dissolved in blood plasma
• Carbaminohemoglobin formation

• Thanx