Blood 1 Flashcards
Body weight percentage of blood
8%
Average volume of blood in F/M
F - 5L
M - 5.5L
What does blood consist of ?
Consists of 3 types of specialized cellular elements
suspended in plasma
What are the three types of cells in blood?
- Erythrocytes
- Leukocytes
- Platelets
What are erythrocytes?
Red blood cells
What are erythrocytes important for?
Important for O2 transport
What are leukocytes
White blood cells
What is the function of leukocytes?
Immune system’s mobile defense units
What are platelets?
Cell fragments
What are platelets important in?
Important in hemostasis
Percentage of blood that is plasma
55%
What percentage of plasmas total weight do plasma proteins compose?
6% to 8%
What are the three groups of plasma proteins?
- Albumins
- Globulins
- Fibrinogen
What are the most abundant plasma proteins?
Albumins
What are the three subclasses of globulins?
- Alpha (α) –
- Beta (β) –
- Gamma (γ)
Alpha (α) globulins function
Transport molecules eg. a1 antitrypsin
Beta (β) globulins function
Inactive precursor proteins eg proteases
Gamma (γ) globulins function
Immunoglobulins (antibodies)
What is the function of fibrinogen?
A key factor in blood clotting
What are the only solutes which do not pass freely
between plasma and interstitial fluid?
Proteins
What can proteins exert across capillary walls?
Exert a significant osmotic effect across capillary walls
What is the osmotic effect of proteins important for?
In distribution of ECF between vascular and interstitial compartments so important in the maintenance of circulatory volume
How much of plasma is composed of water?
90%
What is the function of water in plasma?
Transport medium, carries heat
What is the function of electrolytes in plasma?
Membrane excitability; osmotic distribution of fluid between ECF and ICF; buffer pH changes
What is the function of nutrients, wastes, gases and hormone in plasma?
Transported in blood; blood gas CO2 plays role in acidbase balance
What is the function of plasma proteins in plasma?
In general, exert an osmotic effect important in distribution of ECF between vascular and interstitial compartments; buffer pH changes
What is the function of albumins in plasma?
Transport many substances; contribute most to colloid osmotic pressure
What is the function of Alpha and beta globulins in plasma?
Transport many water-insoluble substances; clotting
factors; inactive precursor molecules
What is the function of gamma globulins in plasma?
Antibodies
What is the funciton of fibrinogen in plasma?
Inactive precursor for the fibrin meshwork of a clot
What is the function of neutrophils?
Phagocytize bacteria
What is the function of eosinophils?
Kills parasitic worms; destroy antigen-antibody complexes; inactivate some inflammatory chemicals of allergy
What is the function of basophils?
Release histamine and other mediators of inflammation; contain heparin , an anticoagulant.
What is the function of lymphocytes?
Mount immune response by direct cell attack or via antibodies
What is the function of monocytes?
Phagocytosis; develop into macrophage in tissues.
What is the function of erythrocytes?
Transport oxygen and carbon dioxide.
What is the function of platelets?
Seal small tears in blood vessels; instrumental in blood clotting.
What is the anatomy of RBCs?
- No nucleus, organelles or ribosomes
- Biconcave discs
What does the biconcave shape of RBCs function for?
Efficient diffusion - Large surface area for diffusion of O2 across the membrane
– Very thin enabling rapid diffusion of O2 between exterior and innermost regions of the cell.
– Very flexible shape allows RBC’s to travel through narrow capillaries without rupturing in the process.
What do RBCs have in their membranes?
Glycoproteins
How is blood classified?
According to what glycoproteins are present on that person’s RBCs
What are glycoproteins also called? x 2
- Antigens
- Agglutinogens
Why are glycoproteins also called antigens?
They can cause immune system to generate antibodies
Why are glycoproteins also called agglutinogens?
They can cause agglutination, or clumping up of cells
What are the three most important antigens on RBCs?
A,B and Rh
Type A
Have A and not B
Type B
Have B and not A
Type AB
Have both A and B
Type O
Have neither A nor B (think zero or
null)
Principles of blood matching
- The immune system of the recipient will attack and destroy RBCs with “foreign” antigens.
- The immune system will not notice and will not be bothered by the absence of an antigen.
- The immune system will not attack “self” antigens.
What is the universal recipient?
AB
What is the universal donor?
O
What tests are used to determine a persons blood type?
Aggluntination test
What is seen on petri dish with no match
clumping is seen and hemolysis occurs
Rh positive or negative
Blood called “positive” if RBCs have Rh D antigen, “negative” if RBCs do not
When does Rh- make antibodies to Rh factor?
Rh- (Rh negative) person does not make antibodies to Rh factor until exposed to it (unlike A,B antigens & antibodies).
Name a haemolytic disease of the newborn
Erythroblastosis fetalis
Details of erythroblastosis fetalis
– Haemolysis of RBCs of fetus which can cause anemia or worse
– May occur when an Rh negative mother & Rh positive father have an Rh positive fetus
Give a treatment for Rh disease
Rho(D) immune globulin
What type of treatment is Rho(D) immune globulin?
Prophylactic treatment (antibiotics to prevent infection)
What does Rho(D) immune globulin do?
Removes Rh positive RBCs from maternal blood before her immune system becomes sensitised to it
When is Rho(D) injected?
Injected within 72 hours after birth of Rh positive baby
NB! Give details of structure/ function of haemoglobin
– Hb red-pigmented protein
– key factor in carrying O2
– an erythrocyte has ~ 280 million Hb molecules
– each Hb molecule has four iron ions which bind four O2 molecules
– each RBC can carry 1 Billion O2 molecules!
– O2 binding is weak to ensure rapid exchange
– O2 binds to Hb when RBCs in lungs
– O2 leaves Hb when RBCs in tissues
– Hb also bind CO2 (from tissue to lungs)
– This buffers the pH of the blood
– CO has higher affinity for Hb than O2 (CO poisoning)
– NO in lungs binds to Hb, which induces dilatation of local arterioles.
Name 2 key erythorocyte enzymes.
- Glycolytic enzymes
- Carbonic anhydrase
Function of glycolytic enzymes.
– Generates energy to fuel active transport involved in maintaining ionic concentrations in cell
– Rely on glycolysis for ATP formation
Function of carbonic anhydrase
– Critical for CO2 transport
– Converts metabolically produced CO2 into bicarbonate ion (HCO3-) - primary form in which CO2 is transported in blood
What is erythropoeis?
Synthesis of new RBCs
Is nuclear DNA present in normoblast?
Yes
Is nuclear DNA present in reticulocyte?
No
Is nuclear DNA present in Mature RBC?
NO
What has RNA in cytoplasm of normoblast, reticulocyte, mature RBC?
Normoblast, reticulocyte
What is in marrow? - Normoblast, reticulocyte, Mature RBC?
All
What is in blood? - Normoblast, reticulocyte, mature RBC?
Reticulocyte and mature RBC
What is erythropoesis stimulated by?
Erythropoietin
Synthesis of RBC
Hemocytoblast (stem cell) -> Proerythroblast -> Erythroblast -> Normoblast -> Reticulocyte (nucleus expelled) -> erythrocytes
Where do erythrocytes form?
In red bone marrow
How long do erythrocytes survive for?
120 days
How are erythrocytes removed?
By macrophages in spleen and bone marrow
What happens to erythrocyte iron once removed?
Recycled back into haemoglobin production
Life cycle of erythrocyte
- Erythrocytes form in red bone marrow.
- Erythrocytes circulate in bloodstream for 120 days.
- Aged erythrocytes are phagocytized in the liver and spleen.
- Heme components of blood are recycled.
- Membrane proteins and globin proteins are broken down into amino acids, some of which are used to make new erythrocytes.
What happens to heme components recycled?
- Heme is converted into biliverdin and then to bilirubin which is secreted in bile from the liver.
- Iron is transported in the blood by the protein transferrin and stored by the protein ferritin in the liver.
How does erythropoetin from kidney stimulate erythropoiesis?
- Kidneys detect reducted O2 carrying capacity of blood.
- When less O2 is delivered to the kidneys, they secrete erythropoetin into blood.
- Erythropoietin stimulates erythropoiesis by bone marrow.
- Additional circulating erythrocytes increase O2-carrying capacity of blood.
- Increased O2-carrying capacity relieves initial stimulates that triggered erythropoietin secretion.
What are the two causes of anaemia and ‘mechanism’?
- reduced Hb in RBCs
- Iron deficiency - Reduced RBC Number
- Reduced cell production
- Increased cell loss
- Haemolysis (membrane changes)
What are the six types of anaemia?
HHARPN
- Hemorrhagic
- Hemolytic
- Aplastic
- Renal
- Pernicious
- Nutritional
Cause of nutritional anaemia?
Iron deficiency (can’t make sufficient haemoglobin)
Cause of pernicious anaemia?
Can’t absorb Vit B12 in GIT (deficient intrinsic factor)
Cause of aplastic anaemia?
Bone marrow cannot produce enough RBCs (Cancer, chemotherapy, radiation)
Cause of renal of anaemia?
Impaired erythopoietin synthesis due to Kidney disease
Cause of hemorrhagic anaemia?
Loosing a lot of blood
Cause of hemolytic anaemia>?
rupture of RBCs
- Malaria (parasite) invades RBCs and causes rupture
- Sickle cell disease (genetic mutation in b-chain of Hb)
Structure of sickle cell anaemia and how?
Defective Haemoglobin molecules join together to make the RBCs stiff and unnaturally shaped
– Crescent or sickle shaped
What occurs in polycythemia?
- Too many circulating RBCs resulting in elevated haematocrit
- Increased blood viscosity
What are the types of polycythemia?
- Primary
- Secondary
What is involved in primary polycythemia?
Tumor of bone marrow; uncontrolled erythropoiesis
What is involved in secondary polycythemia?
- Erythropoietin-induced in response to prolonged reduced oxygen (adaptive mechanism)
- High altitudes, chronic lung disease, cardiac failure
Normal hematocrit level?
45%
Anaemia hematocrit level?
30%
Polycythemia hematocrit level?
70%
Dehydration hematocrit level?
70%
Function of hemostasis?
Prevents blood loss from a broken blood vessel.
3 steps in Hemostasis
- Vascular spasm
- Formation of a platelet plug
- Blood coagulation (clotting)
Vascular spasm function
Reduces blood flow through a damaged vessel
Formation of a platelet plug details
- Platelets aggregate on contact with exposed collagen in damaged wall of the vessel
- Platelets release ADP which causes surface of nearby circulating platelets to become sticky in order to adhere to first layer of aggregated platelets
What is blood coagulation (clotting)?
Transformation of blood from liquid into a solid gel
NB! Platelets (thrombocytes) details
- smallest elements in blood
- lack nucleus
- fragments of megakaryocytes
- make most of mass of blood clots
- release serotonin (vasoconstrict, reduce blood flow to clot)
- secrete growth factors (maintain integrity of blood vessel wall)
- survive 5-9 days (removed by tissue macrophages)
What is Thrombopoeitein and function?
Hormone produced by liver increases number of megakaryocytes and therefore increases platelet production
