Lecture 12 - Blood Flashcards
What is the typical pH range of blood?
7.35-7.45
What is blood plasma?
-blood minus the formed elements
What is blood serum?
-plasma without blood clotting-proteins
What are the different layers of centrifugated blood and what do they contain?
- supernatant (plasma)
- buffy coat (leukocytes)
- precipitate (sedimented red blood cells
What is the average blood volume, % of formed elements, and hematocrit of males and females?
Blood volume:
- males: 5-6
- females: 4-5
Formed elements:
- males: 44-54%
- females: 38-48%
Hematocrit:
- males: 47%
- females: 42%
What are the different types of blood proteins?
Fibrinogen:
- made in liver
- function in blood clotting
- target for thrombin
Albumins:
- made in liver
- exert osmotic pressure on blood vessel walls
Globulins:
-immunoglobulins
What are the characteristics of an erythrocyte?
Red blood cells
- biconcave shape
- devoid of granules and organelles
- contains: lipids, ATP, carbonic anhydrate, and hemoglobin
- protein contents: ~50% integral membrane proteins; spectrin, ankyrin, and actin
What is the average concentration of erythrocytes in males and females?
Males:
-4.3-5 x 10^3 / μL
Females:
-3.5-5 x 10^3 / μL
What is responsible for the biconcave shape of erythrocytes?
- spectrin tetramers (two dimers of α and β spectrin) bind actin
- actin-spectrin network is bound to cell membrane by ankyrin which is connected to transmembrane protein band 3
- protein 4.1 binds at actin-spectrin junctions and also binds to transmembrane glycophorin
What are characteristics of neutrophils?
-polymorphonuclear leukocytes (PMNs)
- 7-9μm
- 3-5 nuclear lobes
- amoeboid phagocytes
- small, numerous granules (lysozymes and protease)
- larger, less numerous azurophilic granules (elastase and myleoperoxidase)
- circulate for 10-12 hours
- 1-2 day life span after circulation
- release enzymes which destroy bacteria such as lysozyme, lactoferrin, and free radical forming enzymes
What are characteristics of basophils?
- 7-9μm
- loculated nucleus (bilobed)
- large, basophils granules: contains serotonin, heparin, and kallikerin (attracts eosinophils)
- can produce leukotreines which increase vascular permeability and slow contraction of smooth muscle
What are characteristics of eosinophil?
- 9-10μm
- BILOBED nucleus
- GRANULES containing major basic protein (MBP)(disrupts parasite membranes), peroxidase, and cationic protein (neutralizes heparin)
- respond in ALLERGIC and PARASITIC infections
- PHAGOCYTIZE antibody-antigen complexes and parasites
What are characteristics of lymphocytes?
- large round, indented nucleus
- small (6-8μm), medium (10-12 μm), and large (up to 18 μm)
- B lymphocytes: precursor of plasma cells
- T lymphocyte
What are characteristics of monocytes?
- 9-12 μm
- largest leukocyte
- eccentrically located, kidney-shaped nucleus
- granular cytoplasm due to small lysosomes
- precursor of macrophages
What are characteristics of platelets?
- derived from megakaryocytes
- 2 μm
- 200,000-400,000 per microliter of blood
- enhance aggregation (secretion of thromboxane),
- promote clot formation, retraction, and dissolution
What is hemostasis? What is the sequence of events that results in hemostasis?
-elimination of bleeding
- constriction of smooth muscles around vessels
- constriction of vessels
- slowing of blood
- promotion of platelet plug
- blood coagulation
Describe the process of platelet plug formation.
- injury of endothelium exposes collagen fibers
- platelets bind to collagen; secrete ADP and convert arachidonic acid to thromboxane (stimulates further aggregation)
- aggregation causes plug formation
- Von Willebrand factor is secreted from Wiesel-Palade bodies in endothelium which facilitates adherence of platelets to wall
What are the steps of the common pathway?
- PROTHROMBIN is activated by FACTOR X, FACTOR V, and C++
- activated prothrombin is converted into THROMBIN
- thrombin and Ca++ activate FIBRINOGEN and FACTOR XIII
- activated fibrinogen converts into FIBRIN
- fibrin forms a MESH in the presence of activated factor XIII
- erythrocytes and other cells are TRAPPED by mesh
What is the intrinsic pathway?
- clotting initiated by injury to the endothelium and exposure of collagen fibers
- all components for clotting are present in the blood
What is the extrinsic pathway?
- blood clotting initiated by release of thromboplastin (factor III) entering the bloodstream
- thromboplastin produced in cell membranes or organelle membranes of damaged tissue
What are the steps of the intrinsic pathway?
- factor XII is activated by collagen and kallikrein
- factor XII activates factor XI along with thrombin factor II
- factor XI activates factor IX
- thrombin factor II additionally activates factor VIII
- factor X is activated by factor IX and factor VIII in the presence of calcium
- factor X activates the common pathway
What are the steps of the extrinsic pathway?
- TISSUE INJURY occurs and tissue release THROMBOPLASTIN
- thromboplastin activates FACTOR VII
- activated factor VII and Ca++ activate FACTOR X
- factor X activates common pathway
How does the formation of a blood clot regulate the dissolution of the blood clot?
- tissue plasminogen activator (t-PA) activity is strengthened by fibrin and converts PLASMINOGEN to plasmin
- PLASMIN dissolves clot
What is leukocyte extravasation and what are the two main steps through which it occurs?
-leukocytes leave the laminar flow of a blood vessels and undergo transendothelial migration
Phases:
- selectin phase
- integrin phase
What occurs during the selectin phase of extravasation?
- P-selectin is expressed on the surface of endothelial cells when inflammatory signals are present
- Sialyl Lewis-x antigens are oligosaccharides present on the leukocyte membrane which bind P-selectin
- binding of antigens to carbohydrate recognition (CRDs) domain on P-selectin causes the leukocyte to roll
What happens during the integrin phase of extravasation?
- occurs after integrin phase
- integrin receptors are activated on leukocyte membrane and bind to ICAM-1 and ICAM-2 (Ig superfamily) on endothelial cell
- integrin receptors are activated on leukocyte membrane and bind VCAM and ICAM on endothelial cell
- binding of integrins with ligand promotes transendothelial migration
What is erythroblastosis fetalis?
- antibody induced hemolytic disease
- occurs when fetal blood type (ABO/Rh) varies from the mothers and the mother develops antibodies to the fetal blood
- occurs after first pregnancy as IgG is produced which can cross the placenta
