L1 Intro to blood-converted.pdf.crdownload

MIHS L1- Phy-Blood By Dr Usha Objective: To discuss the composition and functions of blood Topic outcomes At the end of lecture the student should be able to 1.1. Explain the composition & functions of blood 1.2. describe the differences between plasma & serum 1.3. Describe the method to...

MIHS L1- Phy-Blood By Dr Usha Objective: To discuss the composition and functions of blood Topic outcomes At the end of lecture the student should be able to 1.1. Explain the composition & functions of blood 1.2. describe the differences between plasma & serum 1.3. Describe the method to estimate hematocrit & state the normal range. 1.4. Discuss the reference ranges of blood parameters.  Blood is a vital body fluid, Continuously circulating Formed elements remain suspended in it. Liquid part- (55%) plasma, clear straw yellow fluid. Solid - cellular portion 45%, known as formed elements (corpuscles or blood cells- RBC, WBC, Platelets)). All Blood cells develop from one type of cell called “stem cell” found in the red bone marrow inside the bones of long and flat bones. Stem cells differentiate to RBC, WBC & platelets Bone marrow in the skull, ribs, sternum (breast bone), spine and pelvis, head of long bones. Heart and circulation  Arteries carry blood full of oxygen from heart to all parts of the body. As the arteries get further away from the heart, they get smaller. Eventually they turn into capillaries (smallest blood vessels). They go into the tissues gives oxygen to the cells and picks up the waste gas, carbon dioxide, from the cells. The capillaries are connected to smallest veins in the body. The veins get bigger as they carry the blood back towards the heart. A B A: Before & Centrifuged blood 10 B: After centrifugation sample in Wintrobe’s tube Plasma (55%) showing Packed cells & supernatant Plasma 5 Buffy coat Packed red cells (45%) 0  Components of blood Plasma (55%) Formed elements (45%) Water (91%) Red blood cells Solids-9%: (erythrocytes) Proteins; Enzymes White blood cells Lipids, Glucose, AA, FFA (leucocytes) Electrolytes & minerals Platelets Hormones; Vitamins (thrombocytes) Metabolic waste, bilirubin  Major inorganic molecules are: Na+, Ca2+,Cl-,HCO3- K+,Mg2+,Cu2+,PO43-,protein Fe2+,Fe3+. Organic molecules 7% are plasma proteins 1% are non protein nitrogenous substances (NPN), sugar, fats, enzymes, and hormones. Important solute of plasma that contribute to osmolarity Constituent Concentration *Sodium 150 mmol/l Chloride 100 mmol/L Bicarbonate 24 mmol/L Potassium 3.5-5.0 mmol/L *Glucose 3.4-5.6 mmol/L (60-100 mg/dL) *Blood urea nitrogen 10-20 mg/dL (BUN) ERYTHROCYTES  RBC (Erythrocytes) Attach to oxygen to carry it within the circulation to the tissues. When they get to an area where the oxygen is needed, they give it up and pick up carbon dioxide which they carry back to the lungs. A shortage of red blood cells is called anaemia. The role of the red blood cell in carrying oxygen explains why very anemic people usually feel breathless.  LEUCOCYTES Granulocytes Agranulocytes lymphocytes monocytes neutrophils eosinophils basophils  WBC (Leucocytes) ❖Different types of white cells in the blood in differing amounts. ❖Play a part in the immune response. ❖Response of the body to infection, or anything the body recognizes as 'foreign'. ❖ ❖ Generally have a short life. ❖ Some only live for a few hours, others for days. Cellular elements of blood- Normal values on an avergae Total RBC count 4.5-5.5 millions/c.mm of blood Total Leucocyte count (TLC) 4000-11000/c.mm Neutrophils 50-70% (means per 100WBC’s) Eosinophils 1-4% DLC Basophils 0-1% Lymphocytes 20-40% Monocytes 2-8% Platelet count 150,000-400,000/c.mm differences between plasma & serum SERUM: ❖ Fluid part oozes out or separated from the clot, when the whole blood is allowed to clot. ❖ It is straw- yellow colored ❖ Composition same as that of plasma except, the clotting factors- fibrinogen, and prothrombin and other coagulation factors. ❖ Plasma minus clotting factors=serum.  Functions of blood 1. Respiratory: Transport of respiratory gases (O2, from lungs to tissues; CO2 from tissues to lungs) 2. Nutritive: Transport of nutrients to tissues 3. Excretory: Transport of metabolites from tissues to the sites of elimination through excretory channels of kidney, skin, and lungs. 4. Transport: of hormones, vitamins, enzymes form the source to target tissues 5. Storage: readymade source for water and certain electrolytes, such as glucose, Na+, K+ etc., 5. Regulation of body temperature (high specific heat; high conductivity; high latent heat of evaporation) 6. Defense against microbial infection (has leucocytes, antibodies etc.) 7. Has inbuilt hemostatic mechanism to prevent its own loss (to prevent blood loss after injury) 8. Has buffers to keep pH normal 9. Maintenance of ECF water content of tissues and its homogeneity- plasma is freely interchangeable with interstitial fluid thus helping to maintain composition and tonicity of ECF  Characteristic of RBC's Circular biconcave disk shape 7.5 μm in diameter 2.0 μm thickness ≤ 1.0 μm in the center Advantages of biconcave shape It exhibits remarkable deformability because of its typical shape. This is especially important while the cells are passing through the small capillaries. Has greater surface area , exchange of O2 and CO2 occurs easily because of greater surface area.  RBC’s Have cytoplasmic enzymes Capable of metabolizing glucose Maintains membrane transport of ions Carry Hemoglobin - Hemoglobin is a protein containing haem, is a iron containing pigment red in color, thus gives red color to blood, function is to transport oxygen and carbon dioxide. In an adult, RBCs are produced in the bone marrow Average life span is around 120 days, old RBC’s are self-destructed in the spleen when squeezed through the red pulp of the spleen  MCV (fL) = Mean cell volume or Mean corpuscular volume MCH (pg) = Mean cell hemoglobin MCHC (g/dL) = Mean cell hemoglobin concentration  Disclaimer The texts, tables, figures and images contained in this course presentation are not my own, they can be found on the references supplied or The Web