Blood Flashcards
Total blood volume is ~ ___% of total body weight
7-8%
hematocrit
RBCs; 40-45%
Buffy coat
WBCs and platelets; 1%
Plasma
white solution of electrolytes, plasma proteins, carbs, and lipids
hematopoiesis
production of blood cells; 75% WBC, 25% RBC
Which have a longer lifespan….WBC or RBC?
red blood cells (4months)
cytokines
proteins or peptides released from one cell that affect growth of activity in another cell
cytokines involved in hematopoiesis
erythropoiesis, leukopoiesis, thrombopoiesis
Distinctive shape of RBCs…
increase surface to volume ratio
RBCs major tasks
- carrying O2 from lungs to tissue
- carrying CO2 from tissues to lungs
- assisting in buffering of acids and bases
~96% of dry weight in RBCs consists of….
hemoglobin
A hemoglobin molecule is composed of 4 ________, each entered around a _____ group.
global chains, heme
Each heme group consists of…
a porphyria ring with an iron atom in the centre
Hemoglobin synthesis requires…
iron
2 major groups of WBCs
granulocytes and non-granule containing lymphocytes and monocytes
ganulocytes
contain cytoplasmic granules visualized under microscope
-brief lifespan
3 types of granulocytes
neutrophil, eosinophil, basophil
neutrophil
most abundant leukocyte, contain granules with lysosomal enzymes capable of phagocytosis
eosinophil
granules containing Major Basic Protein (MBP), which is toxic to parasites and other enzymes
-important in response to viruses and in allergic rxns
basophil
least common granulocyte, granules contain histamine, heparin, and peroxidase and play a role in allergic rxns
2 types of non-granule containing WBCs
lymphocytes, monocytes
2 types of lymphocytes
T-cells and B-cells
T-cells
70-80% of all lymphocytes
-responsible for cell mediated immunity, does not involve antibodies
B-cells
responsible for humeral immunity; make antibodies to antigens
monocytes
spend life in peripheral tissues developing into macrophages
monocytes purpose
- phagocytosis of pathogen or cellular debris
- present antigens to lymphocytes
2 special types of granules in platelets
- dense core granules
- alpha granules
dense core granules
contain ATP, ADP, serotonin, and calcium
alpha granules
store con Willebrand factor, platelet fibrinogen, and clotting factor V
Platelets are essential for..
hemostasis (blood clotting)
3 step process of hemostasis
- vasoconstriction
- platelets aggregate into loose platelet plug
- clot: reinforced platelet plug
What triggers vasoconstriction?
- injury to vascular smooth muscle
- release of paracrine signals from damaged endothelial cells or platelets
Describe platelet plug formation
- breach of endothelium exposes interns to collagen, fibronectin, and laminin, causing platelets to bind
- intact endothelium release substances to prevent platelets from binding
von willebrand factor
causes platelets to form molecular bridges between one another
coagulation/clot
a fibrin protein mesh stabilizes the platelet plug into a clot
After coagulation cascade, clot is a…
semisolid mass of platelets and fibrin with RBCs, WBCs, and serum
Intrinsic pathway
surface contact pathway; factor XII converted to XIIa (activated form) to factor Xa through proteolysis
extrinsic pathway
cell injury pathway; factor VII becomes activated VIIa to Xa; protease rxns accusing outside the vascular system
common pathway
factor Xa produced from intrinsic and extrinsic pathway join together with factor Va and calcium to create prothrombinase
prothrombinase converts prothrombin to ..
thrombin
thrombin
a central protease of the coagulation cascade
-also activates factor XIII to XIIIa which assists in forming fibrin polymers into fibrin mesh
fibrinogen
cleaved by thrombin to fibrin monomers
fibrin monomers
spontaneously polymerize to form a gel of fibrin polymers that weaves through plug and traps blood cells
hemophilia
Several diseases in which one of the factors in the coagulation cascade is defective or lacking
Hemophilia A
a factor VIII deficiency
-most common, 80%
Mehophilia B
factor IX deficiency
prostacyclin and NO prevent ..
platelet binding
anticoagulants
antithrombin II, thrombomodulin, protein S and C
fibrinolysis
- breakdown of blood clots
- conversion of fibrinogen into fibrin, and subsequent fibrinolysis
