Blood Composition & Function Flashcards
dont drop out
what is the function of blood
- body’s long distance transport
- regulation
- hemostasis
- immunity
what does blood transport (Hint: N E V H L W)
- respiratory gases: O2 CO2
- Nutrients
- Electrolytes
- Vitamins
- Hormones
- Lipids
- Waste
what does blood regulate?
- body temperature, re-distribution of heat
- pH, ion concentration, Osmolality
- hormones, from gland to target organ
what is hemostasis
complex and efficient pathway to prevent blood loss from a damaged blood vessel and tissue repair
what is blood made up of
- RBC
- WBC
- platelets
- plasma
what is the proteins present in plasma (in order of most to least)
- Albumin (60%)
- Globulin (35%)
- Fibrinogen (4%)
- Regulatory proteins (<1%)
what is the normal hematocrit and hemoglobin levels in male and females respectively
40%-54% and 37% to 47%
14-17 and 12-16
how does blood transport gases
Hemoglobin binds up to 4 oxygen molecules (4 folded polypeptide chains, 2 a + 2 b chains, each with a heme molecule)
Carbonic anhydrase converts CO2 into bicarbonate (HCO3), primary form of CO2 in blood
what is the replacement RBC production process called
erythropoiesis
3 development steps of erythroblasts from proerythroblasts (erythropoiesis)
what is required for this process
- ribosome synthesis in early erythrocytes
- hemoglobin accumulation in late erythroblasts and normoblasts
- eject nucleus from normoblasts and formation of reticulocytes
proteins, lipids, carbohydrates, folic acid, iron, vitamin b12
what two nutrients are required for healthy RBC production
vitamin b12 and folate (folic acid)
they are necessary for the synthesis of thymidylate, which is the nucleotide of thymine which is require for DNA
regulation of erythropoiesis
- lack of oxygen due to various reasons
- kidney (abit of liver, around 90-10)release erythropoietin
- erythropoietin stimulates red bone marrow
- enhanced erythropoiesis increases RBC count
- RBC has increase oxygen carrying capacity
recycling of RBCs
- healthy RBC functions for 100-120 days
- aged or damaged RBCs are eaten by macrophages in the spleen, liver, bone marrow
- hemoglobin is broken down
- globin > amino acid
- iron binds to transferrin and released into blood
- food nutrients absorbed by intestine and released into blood
- all these raw materials into blood is for erythrocyte synthesis
Anemic, Polycythemia definition
Anemic means lower O2 carrying capacity in blood either through excessive bleeding or low Hb levels
Polycythemia means excess blood or low plasma volumes, both resulting in high hematocrit numbers
Everything about types of blood and compatibility
Type A blood - type A antigen, type B antibody
Type B Blood - vice versa
Thus, A cannot give B, as A will view type B antigen on type B blood as a foreign object and will attack it, causing clumping (agglutination) and the hemolysis
type AB blood got both A and B antigen
type O blood got no antigen
blood transfusion reaction? (A F H)
allergic - rashes/hives, facial flushing
febrile - fever, chills, anxiety, headache, tachycardia, tachypnea
hemolytic - chest pains, low back pains, low BP, high Resp rate, tachycardia
how does vasoconstriction occur, and its purpose
Adenosine Diphosphate and thromboxane A2 to help stimulate smooth muscle contraction and vasoconstriction
slows down blood flow and reduces blood loss, allowing time for platelets and coagulation
Platelets structure and lifecycle
no nuclei, contains contractile proteins actin and myosin, contains granules ADP, calcium, and growth factors PDGF and VEGF, contains factor VIII
PDGF - platelet derived growth factor
VEGF - vascular endothelial growth factor
Hemocytoblast > megakaryoblast > promegakaryocyte > megakaryocyte > platelets
formation of platelet plug
- exposed collagen at the vessel’s injury attracts circulating platelets (vWF forms bridge between collagen and platelets)
- activated platelets release ADP and thromboxane A2, attracting more platelets
- newly attracted platelets release even more ADP and thromboxane A2
- Fibrin forms a mesh that traps RBCs and platelets, forming the clot
- undamaged endothelium releases prostacyclin and nitric oxide to prevent platelets from aggregating, keeping it on the site of injury
Intrinsic vs Extrinsic pathway differences
Intrinsic is
- for internal vessel damage
- takes longer
- require factors XII, XI, IX, VIII and calcium
Extrinsic is
- external vessel damage
- shorter time
- require factor VII and tissue factor (III) and calcium
What is the common pathway
Factor X > Xa
Factor V > Va
with calcium and platelet factor 3
- become a prothrombin activator
Prothrombin (II) into thrombin (IIa)
Activated fibrinogen (I) into fibrin and factor XIII into factor XIIIa with calcium
together they make a cross-linked fibrin polymer
What coagulation factors are affected by Vitamin K (or Warfarin)
Factors X, IX, VII, II
Remember year 1972 to help
Thrombin (IIa) function in hemostasis
Converts fibrinogen to fibrin
Activated Factor XIII (helps stabilise fibrin mesh)
release PF3 from platelets
release tissue factor
enhances platelet aggregation
enhances own generation
Name for the process of clot dissolution
fibrinolysis
Fibrinolysis order of operation
- plasminogen is made from the liver, trapped within the clot during coagulation
- surrounding tissue and undamaged endothelial cells release the tPA
- plasminogen is cleaved into plasmin by proteases such as tPA (tissue plasminogen activator), thrombin, Factor XII
- plasmin digests fibrin, dissolving the clot.
Phagocytic WBC remove the remains
Different blood clotting disorders
thromboembolism - inappropriate clotting
Thrombocytopenia - too little platelets in the blood
Hemophilia - lack of blood clotting factors
tests for the 2 different pathways and purpose
Prothrombin time (extrinsic)
normal timing would be 11-13 seconds
activated partial thrombinplastin time (intrinsic)
normal range is 25-40 seconds
both tests can help identify any issue or deficiency with any of the clotting factors required for the specific pathway and narrow it down to a cause
what is INR
international normalised ratio
Prothrombin test time divided by the normal Prothrombin test time
Higher the value, the slower your clotting time
types of blood cells
platelets
granulocytes
erythocytes
monocytes
lymphocytes
types of WBC (N E B M M D)
macrophages
dendritic cell
neutrophil
eosinophil
basophil
mast cell
