IC2 Flashcards
what is the function of blood
1) transport
2) regulation
- temperature by redistributing heat
- ion and pH composition in the interstitial fluids
3) protection
- blood loss
- infections
what is hematocrit and what are the percentages for males and females
relative vol of RBCs out of the total blood volume.
M= 44-46%
F=40-42%
appx
what are the 4 layers of blood and what are their percentages
1) plasma 55%
2) leukocytes
3) platelets
both form the buffy coat. this is <1%
4) rbc or erythrocytes 45%
what is the % composition of plasma
water 92%
protein 7
solutes <1
what are the proteins in plasma and their functions?
albumin,
- trnasport of lipid solube substacnes like drugs, hormones
- maintain osmotic pressure due to negative charge that pull water back into the blood vessels
globulins,
- clotting and immune function
fibrinogen
- clotting
function of erythrocytes (and what they contain)
contain
hemoglobin to transport o2
carbonic anhydrase to transport co2
shape and size of erythrocytes
7.5um diameter
1-2um thickness
flexible
biconcave disk with large surface area to volume ratio and easy diffusion of o2
appx >97% hemoglobin.
how much o2 can 1 erythrocyte transport
10^9
what is the lifespan of RBC
100-120 days or 3-4months
describe hemoglobin
4 chain = 2 alpha 2 beta
each binded to 1 heme pigment
= contains Fe which binds to oxygen,
therefore one hemoglobin = transport 4 molecules of oxygen.
how much o2 can water transport in blood (free o2) and how much increase with hemoglobin?
around 5ml/L
increase 40 fold with hemoglobin
what is the rate of RBC replacement (erythropoiesis)
2-3 x 10^6 RBC/second
what is the place of erythropoiesis according to age
fetus = yolk sac, then liver, spleen, lymph node.
<5 = all of bone marrow
5-20 = bone marrow of the sternum, vertebrae, ribs, proximal ends of long bones
>20 = bone marrow of the sternum, vertebrae, ribs.
how is erythropoiesis controlled (include pathology)
controlled by release of erythropoietin by the kidneys.
triggered by
- hypoxia
- less o2 avail
- anemia
- increase tissue demand for o2
- reduced blood flow to kidney
- blood donation.
describe erythropoesis and the rbeakdown of rbc
phase 1: ribosome synthesis in early erythroblasts
2: hb accumulate in late erythroblasts and normoblasts
3: ejection of nucleus from normoblasts and formation of reticulocytes.
aged rbc get engulfed by macrophages of liver, spleen, bone marrow. haemoglobin is broken down into:
1) heme
(i) iron = stored as ferritin (released to blood from liver), hemosiderin
(ii) bilirubin (yellow) = blood from liver = bile = intestines = stercobilin = faeces. (related to jaundice)
2) globin> amino acids
what is anemia and what are the symptoms
reduction of RBC or reduction in the o2 carrying capacity of hb.
usually presents with low metabolism, = fatigue, paleness, SOB, chills
explain:
nutritional anemia
dietary deficiency = iron, folic acid, needed for erythropoiesis
explain:
aplastic anemia
failure of bone marrow to make sufficient rbc
explain:
renal anemia
kidney disease = lack of erythropoietin
explain:
anemia caused by malaria
plaasmodium falciparum amplify in RBC = rupture.
explain:
haemorrhagic anemia
loss of blood
explain:
sickle cell anemia
mutation in beta globin gene = hemoglobin aggregate in low o2 conditions = present = rupture RBC membrane.