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.
explain:
thalessemia
thalessemia = low production of hemoglobin (hereditary)
explain
pernicious anemia
lack of vitb12 or intrinsic factor
what is polycythemia/erythremia and what are the side effects
too much rbc, too high hematocrit
primary - : caused by tumor/tumor like condition in the bone marrow = overproduction = 7-7x10^9 rbc/ml
others: altitude training, cancer.
may also be caused by dehydration
causes blood to become viscous = plug capillaries = poor o2 delivery
explain erythroblastosis fetalis
in erythroblastosis fetalis = rhesus factor positive rbc of fetus destroyed by anti-rh antibodies of rh- mother.
what is normal reticulocyte count in percent
0.8-1 percent
what is MCV
mean corpuscle volume
refers to avg vol or size of your rbc
what is MCH
mean corpuscular hemoglobin
refers to avg amt of hemoglobin in rbc
what is MCHC
mean corpuscular hemoglobin concentration
refers to avg conc of hemoglobin in rbc (amt/vol)
what is RCW
red cell distribution width
refers to how the rbc size varies
if high == early indicator of anemia
leukopenia vs leukocytosis?
leukopenia = too few WBC. may cause by opportunistic infections. may be result of radiation, chemotherapy, chemicals, viral infections…
leukocytosis = WBC > 1.1 X 10^7/ml
what are leukemia and lymphomas?
cancer of the white blood cells,
wbc up to 5x10^8/ml (normal is 4-11 x 10^6)
what are the three phases of hemostasis (and time taken)
1) vasoconstriction or vasospasm: IMMEDIATE
2) platelet plug: seconds
3) fibrin clot: minutes
how long for clot retraction AND repair (and what happens)
20min to 1h
1-2 weeks
clot retraction: clot stabilised by squeezing serum from fibrin clot.
repair: PDGF stimulates vascular smooth muscle cells to build new vessel walls.
VEGF stimulates endothelial cells to multiply and restore inner endothelial lining
what happens during the vasoconstriction phase?
endothelial cells of opposite sides may stick together. endothelial cells contract to expose basal lamina. reduces blood loss, but not sufficient.
vasoconstriction initiated by sympathetic nerves. mediated by vascular smooth muscle cells.
last for 30mins to sometimes hours
providing time for platelet and coagulation phase.
what happens during the platelet phase
go in detail
damaged endothelial wall exposes collagen, causing platelets to bind to the collagen (through von willebrand factor produced by platelets) = activates platelet = morphological change = release of platelet factors (platelet agonists: ADP, thromboxane A2) = ADP attracts and activates more platelets, while tbx a2 promotes aggregation and further vasoconstriction=fibrinogen links platelets through glycoprotein receptors.
properties of platelets
including organelles and other cell content
fragmenets of megakaryocytes (1 megakaryocytic = 2000-3000 platelets).
platelets lack nuclei, contain contractile proteins (actin, myosin), and organelles (mitochondria = release ADP, ER/golgi = storage of ca2+ and synthesis of enzymes), enzyme systems (for prostaglandins), growth fators (PDGF, VEGF for endothelial cells to mend and grow and platelets to clot), factor xiii (fibrin stabilising factor).
detail the coagulation cascade
all three pathways
intrinsic pathway:
exposure to collagen fibres/exposure to foreign surface:
- platelet phospholipids = 12 to 12a = 11 to 11a = in the presence of ca2+, 9 to 9a
(4, 9, 11, 12 and 8 )
extrinsic:
damaged tissues release tissue factor/thromboplastin(factor 3) = 7 to 7a
(3, 7)
in the presence of ca2+ and 8a (intrinsic) or ca2+ and 7a (extrinsic), 10 to 10a = in the presence of ca2+ and 5a, prothrombin = thrombin, which causes conversion of fibrinogen to fibrin AND fibrin to fibrin meshwork (stabilise fibrin mesh) (in the presence of 13a)
what is factor 4, 3, 2, and 1
4 = calcium ion
3 = tissue factor or thromboplastin
2 = prothrombin
1 = fibrinogen
which clotting factors require vitamin k
2, 7, 9, 10
what are the clotting factors form 1 to 13
foolish people try climbing long slopes after Christmas some people have fallen
1 = fibrinogen
2 = prothrombin
3 = tissue factor
4 = calcium
5 = labile factor
(6 no longer used_
7 = stable factor
8 = antihemophilic
9 = Christmas factor
10 = stuart prower
11 = plasma thromboplastin
12 = hageman factor
13 = fibrin stabilising
which factors are not made in the liver
3 = dmaaged tissue or activated platelets
4 = diet, bone, platelet
8 = platelets, endothelial cells
what are the other moa of thrombin
enhances its own generation from prothrombin via positive feedback
activates factor 13 to stabilise fibrin mesh
enhances platelet activation and aggregation = stimulating release of pf3 from platelets to activate intrinsic pathway
stimulate conversion of fibrinogen to fibrin
how fast does intrinsic pathway occur and what are the triggers
VS extrinsic pathway
intrinsic= internal damage causing exposure to collagen OR exposure to foreign surface like glass
(internal damage)
occurs in minutes
vs
extrinisic = tissue exposed secondary to external trauma; damaged tissue releases tissue factor.
(external damage)
occurs in seconds
how is blood clotting regulated describe the two molecules
prostacyclin: released by intact endothelial cells thus inhibiting platelet activation and limiting the spread of clotting.
serotonin = high concentrations inhibit ADP
blood clot itself alsolimits sprea dof thrombin and other procoagulants
what are endogenous anticoagulants
antithrombin 3, heparin, thrombomodulin, tissue plasminogen activator, smooth surface of endothelial
what are artificial anticoagulants
chelators (citrate, edta), VKA, DOAC
how does fibrinolysis occur
plasminogen trapped inside the clot is inactive
tissue and vascular endothelial cells release tissue plasminogen activator to cleave the inactive plasminogen to the protease plasmin = digest fibrin = dissolve clot = removed by macrophages.
what factors cause the different types of hemophilia
A: 8
B: 9
C: 11
what are some blood clotting disorders
hemophilia, thrombocytopenia, vit k deficiency (required to produced factors 2,7,9,10), liver disease (required to produce most clotting factors and also produce bile to absorb vitK)
what are the blood coauglation tests
PTT, PT, INR
what does PTT measure, indication, normal range, uses what
intrinsic and common pathway (1,2,5) (8,9,10,11,12)
for monitoring heparin therapy
normal range 25-39
uses: citrated plasma, ca2+, phospholipid, kaolin clay(stimulate foreign surface)
what does PT measure, indication, normal range, uses what
extrinsic and common pathway (1,2,5) (7, 10)
for monitoring warfarin therapy
normal range 12-15
uses citrated plasma, ca2+, tissue factor
what is inr and what is normal range
pt of patient to pt of healthy person
normal 0.9-1.3
