TOPIC: 5 - BLOOD

what is haematocrit

percentage of blood volumn that is made up of erythocytes - 47% in men 42% in women

what happens with haematocrit with anaemia and polycythaomia

anaemia - fall to 15%

polycythaemia - rise to 75%

what are red blood cells

erythocyte 7.5cm diametre

97% content is hemoglobin gas - transporting protein

anucular and no mitrocondira

describe haemoglibin

consists of four polypeptide chains - 2 beta 2 alpha - each chain holds one haeme group

each can hold 4 oxygen which bind with iron

one RBC has 250million HB molecules

• oxyhaemoglobin - saturated with oxygen

• deoxyhaemoglobin - no oxygen returning to lungs

what are the three functions of blood

1. transporting materials and gasses between body tissue, lungs, kidney, gl tract, hormones

2. regulation: buffering changes in PH, heat ditribution, fluid distribution

3. protection: prevent blood lossand destroy antibodies and WBIs to tissue

components of blood

plasma 55%

buffy coat: leukolytes and paletes 1 %

erythocytes 45%

what is plasma

straw coloured, sticky, 90% water, electrolytes, amino acids, plasma proteins , antibodies, lipids, co2, nitrogenous waste, hormones

what is plasma protein

albumin 60% - buffer, carry protein

globulins 35% - carry protein

fibrinogen 5 % - inactive precursur to fibrin - important for blood clotting

formed elements in blood

plalletes - fragments of cells

leukocytes - white blood cells

erthocytes - red blood cells

what is haematocrit

percentage of blood vollumn made up of RBC - 47 in men and 42 in women

what conditions see a change is haematocrit

anaemia - fall to 15%

polycythamia - rise to 75%

how are red blood cells formed

occurs in bone marrow and circulates for 120 days

how are red blood cells destroyed

age with time and worn cell surface - glycocalyx stimulate phagocytes by macrophages in the spleen and liver

what does rapid cell division require

vitb12 aand folic acid - anaemia occurs if vitamines are deficient

diatary requirements of erythropoisesis

amino acids, lipids, carbohydrates, iron, vitB, folic acid

where does body store iron

65 percent in HB, the rest in liver and bone marrow

what happens to Hb from RBC

RBC breakdown in spleen and liver followed by HB degradation -

globin portion is lysed - releasing amino acids which are reused

heme units are lysed releasing bilirubin and iron

bilirubin is picked up by liver and secreted into intestines in bile where is is metabolised to stercoblin

iron is bound to transferrin and released to blood from liver as needed for erythropoisis

what is anaemias

insufficent O2 carrying capacity in blood due to low RBC or HB: fatigue, breathless, chills, pale

aneamia too few RBC formed

iron deficency aneamia - erythocytes are called microcytes - small and pale

permicious aneamia - autoimmune disease - vitB deficency - lack of intrinsic factor in stomach

aplastic anaemia - radiation and chemicals

renal anaemia - kidney damage - EPO formed in kidney

abnormal blood loss aneamia

hemorrhagic anaemia -

anaemia from too many RBC destroyed

haemolytic anaemia: hemoglobin abdormalities, mismatched blood, parastitic infections

thalassemias: typically occur in mediteranian anncestery - globin chain abdormalities, electrolytes are thin, delicate and deficient in hemoglobin

sickle cell anaemia: hemoglobin S - change in 1 of 147 amino acids - beta chains link together under low oxygen conditions forming stiff rods - african people

what is polycythemia

abnormal amount of ethryocytes which increase blood viscosity

what is blood doping -

atheletes competing in arearobic events - athletes blood in drawn and stored for later injection - risk of stroke and heart failure

what are anticoaluglants

reduce blood clotting

vitamin k - essential for production of several procoaguants by the liver

warfarin - interfers with action of vit k

asprin - used to prevent unwanted blood clotting, reduces myocardial infection by 80%

what is mismatched blood transfusion

transfusion reaction: donars RBC will be bound by recipiant plasma antibodies

what are agglutinogens

antigens - located on surface of RBC

what are agglutinins

antibodies - distributed in the plasma

blood types

a = a antigens b antibodies

b = oppositve

O = no antigens both antibodies

ab = both antigens no antibodies

RH blood groups

abcence RH negative - has = RH positive

which plasma protein is most common

albumin 60% - buffer, important carrier protein, maintains vascular COP

what is oxyhaemoglobin

saturated in oxygen

changes into 3d shape and becomes ruby red

what is deoxyhaemoglobin

oxygen detaches from iron and returns to original shape - ‘reduced’ hemoglobin

what is carboxyhaemoglobin

20% of CO2 transported in the blood combines with haemoglobin - binds with aminoacids

6 events of red blood cell life

1. low O2 levels in blood stimulate kidneys to produce erythropoietin

2. erthryopoiten levels in blood rise

3. erythropoietin and necessary raw materials in blood promote erythropoiesis in red bone marrow

4. new erythrocytes enter blood stream

5. aged and damaged red blood are englufed by macrophages if spleen, liver and bone marrow, hemoglobin is broken down

6. raw materials are made available in blood for erythrocyte synthesis

what is clot retraction

within 30-60 minutes - actin and myosin filaments contraction

what is clot resolution

coagulation — clot — fibrinolysis — removes unwanted clots

what occurs during DVT

embolus travels becomes lodged in pulmonary arteries preventing gas exchange

what is varicose valves

when valves fail causing dilated and tortuous veins

• great saphenous - typical

which veins drain into hepatic portal vein

gastric, splenic, inferior mesenteric, superior mesenteric