BLOOD What is blood Functions of blood What
BLOOD • What is blood? • Functions of blood? • What is it made of? • What blood types are there?
What is BLOOD? How much blood do we have in our body? 5 L which varies by age, sex, water balance • Liquid Connective Tissue • Made up of 2 parts • 45% Formed Elements [RBC, WBC, Platelets] • 55% Plasma [ Intercellular fluid]
Functions of Blood • Transport- nutrients, electrolytes, water gases [O 2, CO 2], waste, hormones • Protection- defense against foreign agents [WBCs- remove pathogens, platelets- clot ] • Regulation- chemical buffers [p. H 7. 4, acid/base balance], temp-conduct heat from core to exterior via lungs/skin
What is Blood made of? • Plasma- [55%] 3. 5 L of adult body wt – 92% water – 8% protein, nutrients, electrolytes, gases, hormones, enzymes, vitamins, waste • Formed Elements- [45%] cells – WBCs, RBCs, platelets
• Hematocrit- packed cell volume of solids [RBCs] in a given amount of blood • RBCs increase with dehydration • • Expressed as a % Males= ave. 47% Females= ave. 42& Children= 38 -49%
Hematopoesis-Blood Cell Formation • 30 Trillion cells which is a constant # • Location- Stem Cells in Bone Marrow 4 TYPES: 1. RBCs 2. Platelets 3. WBC [mono/granulocytes] 4. WBC [lymphocytes- T & B]
• Erythropoesis- RBC formation • Leukopoesis- WBC formation • What is platelet formation called? • THROMBOPOESIS
RBC aka Erythrocytes • • • Make up 95% of formed elements Biconcave discs Transport respiratory gases (O 2 and CO 2) No mitochondria, no nucleus b/f birth – formed in the liver, spleen, yolk sac after birth – formed in the bone marrow B vitamins, Iron (Fe) needed in diet to make Hemoglobin – iron-based protein compound Live for 120 days
Erythropoesis- RBC formation • Erythropoetin- [EPO] hormone released from the liver and kidney to stimulate red bone marrow to create RBCs. • High Altitudes? What happens? • Air thins= decrease O 2
Pathologies • Anemia- decrease in the # RBCs or ability to carry O 2
Sickle Cell Anemia • Shape of RBC is sickleshaped • Genetic • Mediteranian and Af. American • Decrease amt O 2 carried • Joint pain/swelling • B vitamin needed for Fe production
WBCs aka Leukocytes • • Effective in fighting disease Agranulocytes Granulocytes Specific to certain infections
Platelets aka Thrombocytes • Fragments of megakaryocytes • No nucleus • Play a role in hemostasis (stopping blood loss)
Hemostasis-Prevent Blood Loss • Step 1 – Smooth muscle spasm of blood vessel wall • Step 2 – Platelet plug formation • Step 3 – Coagulation
Coagulation • Tissue damage causes the release of – Thromboplastin (from vessel wall and platelets) converts, with the help of calcium) Prothrombin Thrombin (an enzyme, helps) (a protein in to convert) the plasma) Fibrinogen Fibrin (a protein in (Long strands the plasma) of protein)
Clotting Conditions • Hemophilia- inability to clot, missing a clotting factor # 8 • Thrombus-unwanted clots • Embolus- thrombus that breaks away – Lead to stroke or heart attack
Blood Types [A, B, AB, O] • Antigen: Protein found on SURFACE of RBC – Two types: Antigen A and Antigen B – Antigen present gives blood type • Antibody: Protein found IN PLASMA – Two types : Anti A and Anti B
• Agglutination- process during transfusion when the antibody [plasma] of the donor and the antigen [RBC] of recipient are NOT compatable. • RBCs clump
Blood Compatability
AB + = Universal Recipient O- = Universal Donor
Rh System • Based on the Rhesus Monkey • Antigen on RBC surface [D Antigen] – D is present = Rh + – D absent = Rh – • Rh+ CAN ONLY GIVE to Rh+ • Rh- CAN GIVE TO BOTH + and - ** Antibodies in plasma are NOT automatically present…. . so exposure of Rh+ person to a Rhblood will produce Anti-Rh [D] antibodies. Sensitization: Rh- builds up antibodies [anti-Rh] against Rh+.
Erythroblastosis Fetalis- damage to organs[brain] in fetus; goes after RBCs 1. First child born Rh+ = okay 2. Mom builds up antibodies against Rh+ --blood crosses the placenta to mom 3. Rh. OGam is given to mom after 1 st Rh+ child to prevent Rh+ antibody build up 4. Second child born Rh+ = okay if mom given Rh. OGam --not okay if no Rh. OGam, antibodies cross placenta and attack RBCs of fetus
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