Lecture 13 & 14 : Blood Flashcards
Why is the blood called the fluid of Life, growth & health?
- life : transports oxygen
- growth : transports nourishment
- health : transports disease fighting substances
What is blood?
- a liquid tissue & transport medium
What are the functions of blood?
- Transports cells, antibodies, and other humoral factors
- Aids in maintaining water balance and pH
- Helps regulate body temp.
- carries platelets and factors that ensure clotting and prevent blood loss
What is the pH, density & quantity of human blood?
- pH : slightly alkaline (7.40 +.05)
- density: heavier than water ( 1.057 +.009)
- Quantity: average of 5 liters of blood
What is the main composition of blood in humans?
- Plasma :
- liquid portion containing molecules, nutrients, wastes, salts and proteins.
- Formed (cellular) elements :
- RBCs (erythrocytes) + WBCs (leukocytes) and platelets (thrombocytes)
How can blood be separated?
- By spinning the blood in a centrifuge with an anticoagulant added to prevent clotting.
How is the composition of blood divided?
- formed cellular elements : occupy 45%, and settle at the bottom of the tube as a dense red pellet, containing red blood cells
- Buffy coat of leukocytes and platelets ( less than 1%)
- plasma : occupies 55% as a yellow colored liquid at the top of the test tube.
What will happen if an anticoagulant is not added?
- the RBCs and WBCs will clot up and the plasma is called a serum.
What is the percentage, function and source of water in plasma?
- 90% to 92%
- maintains blood volume & transports molecules
- absorbed from intestine
What is the percentage, function and source of plasma proteins in plasma?
- 7% to 8%
- maintains blood osmotic pressure and pH
- liver
- albumin : transports bilirubin
- globulin : transports cholesterol and fights infection
- fibrinogen : cloys blood
What is the percentage, function and source of salts and ions in plasma?
- less than 1%
- maintains blood osmotic pressure and pH, aids metabolism, regulates membrane permeability
- absorbed from intestine
What is the function and source of gases in plasma?
Oxygen : cellular respiration & lungs
Carbon dioxide : end product of metabolism & tissue
What is the function and source of nutrients in plasma?
- food for cells & Absorbed from intestine
What is the function and source of nitrogenous waste in plasma?
End product of metabolism & excreted by kidneys, the liver is the source.
What is the function and source of hormones and vitamins in plasma?
aids metabolism & variety of sources.
Describe Red Blood Cells:
- small ( 7-8 um diameter )
- bright red to dark purple
- mature RBCs lack nucleus
- 4-6 10^6 mm ul
- 25 trillion RBCs exist per adult
- each RBC contains 250 million hemoglobin molecules ( bright red protein )
Describe hemoglobin in red blood cells
- contain 4 globin protein chains, each with a heme ( iron containing group )
- iron combines with oxygen and is carried in the blood
- lack of RBCs causes anemia
How does Hemoglobin function?
- as blood passes the lungs, oxygen attaches to the hemoglobin
- as blood passes tissue, the hemoglobin releases the oxygen ‘
- the empty hemoglobin then bond with CO2 and other waste gases in the tissue and carry it away
How are RBCs made? What is their life span and how are they destroyed?
- made in the red bone marrow (skull,ribs,vertebrae and ends of long bones)
- before a RBC leaves the bone marrow, it loses its nuclear and synthesize hemoglobin.
- 120 days
- destroyed mainly in the liver and spleen by phagocytes
How are blood groups determined?
- by the absence or presence of specific glycoproteins on the cell membranes of RBCs
- classified by ABO and Rhesus factor
What happens with an incompatible donor?
- incompatible donors cause transfusion reaction, resulting in hemolytic anemia, renal failure, shock and death.
How do you determine compatability?
- Blood typing
Place a drop of anti A,B and Rh antibodies on a slide
Add a drop of the persons blood
If agglutination occurs, this is the person’s antigen on his RBCs
What is agglutination?
The binding of an incompatible blood type, causing antigens and antibodies to combine
What is Rhesus (Rh) factor ?
- antigen D, Rh-positive people are 85% while Rh-negative are 15%
- during pregnancy, if the baby is rh-positive and the mother is rh-negative, the mom’s anti-Rh antibodies may leak and destroy the child’s RBC’s
- leading to brain damage, mental retardation and death of fetus.
