Hematocrit Ratio PDF - Physiology Practical 2

Hematocrit Ratio Faculty of Physical Therapy Physiology Practical 2 Dr. Marwa Taha Composition of Blood Blood is composed of two parts: 1. Plasma: It constitutes 55% of blood. This is the fluid part of blood. 2. Cellular comp...

Hematocrit Ratio Faculty of Physical Therapy Physiology Practical 2 Dr. Marwa Taha Composition of Blood Blood is composed of two parts: 1. Plasma: It constitutes 55% of blood. This is the fluid part of blood. 2. Cellular components: It constitutes 45% of blood. Red Blood Cells (RBCs, Erythrocytes). White blood cells ( WBCs, leucocytes) Platelets (Thrombocytes).Platelets (Thrombocytes)  RED BLOOD CORPUSCLES (RBCs) ERYTHROCYTES ₋ Shape: Non-nucleated Biconcave discs provide a larger surface area for diffusion of O2 and CO2 across the membrane, and no mitochondria. ₋ RBCs Count: - In adult males: 5.4 million/mm3. - In adult females: 4.8 million/mm3. - It is higher in hypoxia (newborn infants, athletes, and high altitudes). - It is decreased in old age. ₋ Life Span: 120 days.  Packed cell volume ( PCV ) Hematocrit value ( Hct) Definition: the volume occupied by erythrocytes in a certain volume of blood, expressed as a percentage of the volume of erythrocytes to the whole blood. Principle: when the blood is centrifuged in a heparinized capillary tube at high speed, the erythrocytes will be sedimented at the bottom. The red cell column is called as packed cell volume or hematocrit (cell volume%). 𝑉𝑂𝐿𝑈𝑀𝐸 𝑂𝐹 𝑅𝐵𝐶𝑠 PCV= × 100. 𝑉𝑜𝑙𝑚𝑒 𝑜𝑓 𝑤ℎ𝑜𝑙𝑒 𝑏𝑙𝑜𝑜𝑑  Packed cell volume ( PCV ) After centrifugation, three layers will appear in the capillary tube. 1. Clear plasma at the top (lighter , 90% water). 2. Whitish buffy coat layer at the bottom (WBCs & platelets).. 3. Column of red at the bottom (heavier). Normal values: Male ≈ 46% (38 - 48%). Female ≈ 42% (35 - 45%). Steps of the experiment - Sterile the finger with alcohol. - Puncture the finger with a sterile lancet. - Heparinized capillary tube filled with blood. - Plasticine. - Microcentrifuge for 5 mins at 15000 RPM. - Put on the hematocrit reading scale (chart). Steps of the experiment Micro-hematocrit scale  Clinical significance Increased Hct is due to: Polycythemia (increase volume of RBCs). Hypoxia (high altitude, heart failure & lung disease). Dehydration e.g., diarrhea and vomiting (decrease volume of the blood). Venous blood (CL shift phenomenon, Swelling of RBCs)  Clinical significance Decreased Hct is due to : Anemia (decrease in number or size of RBCs). Hydration (increase volume of the blood). Pregnancy (increase volume of the blood).  Quiz What does a hematocrit reveal? A. The ability of the body to fight infection B. The ability of the blood to clot C. How much oxygen the blood can carry D. The count of platelets in the blood  Quiz Which substance allows RBCs to transport oxygen? A. Erythropoietin B. Thrombin C. Fibrin D. Hemoglobin  Quiz Hematocrit is increased in: A. Dehydration B. Pregnancy C. Anemia D. Thalassemia  Quiz One molecule of hemoglobin A. Contains two alpha globin proteins and two beta globin proteins B. Contains one heme group C. Contains 2 atoms of iron D. Can carry 12 molecules of oxygen  Quiz In a red blood cell, carbon dioxide is attached to the A. Iron of the Hemoglobin B. Amino acids of the Globin C. Plasma membrane D. Heme of the hemoglobin  Quiz Each hemoglobin molecule; A. Has four heme groups B. Has four polypeptide chains C. Transports four oxygen molecules D. All of the above are true