Hematology Flashcards
Main components of blood
- Red Blood Cells (Gas transport)
- Leukocytes (Immune functions)
- Platelets (Hemostasis)
- Plasma (Contains hormones and other nutrients)
Granulocytes & Agranulocytes
Granulocytes:
- Neutrophils
- Basophils
- Eosinophils
Agranulocytes:
- Lymphocytes
- Monocytes
Composition of blood plasma and the functions of plasma proteins
Blood plasma is mostly water, acting as a transport medium.
Also contains
- Electrolytes
- Nutrients
- Waste
- Gases
- Hormones
Plasma proteins:
- Contribute to osmotic pressure
- pH buffers
- Transport certain substances
- Clotting factors (fibrinogen)
Terms related to blood cell formation (5)
Hemopoiesis:
Blood cell formation
Leukopoiesis:
Formation of WBC’s
Erythropoiesis: Formation of RBC’s
Colony stimulating factor: Regulator of which types of blood cells are created from stem cells. Many different types, which affect different cell production.
Pluripotent stem cells: Precursor to all different types of blood cells.
Myeloid stem cells V Lymphoid stem cells
Myeloid stem cells produce Platelets, Granulocytes, Erythrocytes and Monocytes.
Lymphoid stem cells produce lymphocytes
Evolution of an Erythrocyte
Pluripotent stem cell -> Myeloid stem cell -> proerythroblast -> early, intermediate, late erythroblasts -> reticulocyte (released into blood stream/ loss of nuclei) -> mature erythrocyte
Why are Folate and Vit. B12 and iron imperative for erythropoiesis?
Folate and Vitamin B12 are needed for the synthesis of DNA and cell division.
Iron is required for formation of hemoglobin.
How does EPO regulate erythropoiesis?
Erythropoiesis is stimulated by low blood O2 levels. This is sense by the liver and kidneys which stimulate red bone marrow to produce more erythrocytes.
More erythrocytes in the blood now means a higher blood O2 level and EPO release is decreased.
Erythrocyte degradation
Because RBC’s contain no nucleus, they cannot divide or repair themselves so eventually they die and release all their contents into the blood stream.
- Heme is separated into iron and biliverdin
- Globin is broken down into amino acids
Amino acids are used to synthesize other proteins
Iron is used to make new RBC’s
Biliverdin goes to the liver to make bilirubin. Partly for bile and the remainder is waste.
What is Jaundice and how does it occur?
Jaundice is a yellowing of the skin that occurs from the build up of bilirubin. This is from RBC’s dying and not being expelled in waste.
Excess amount of bilirubin can be toxic to the nervous system.
What is the goal of hemostasis?
To stop bleeding.
The 3 phases of hemostasis
Vascular Phase:
- Temp. constriction of vessel in response to nervous system reflexes.
- This is to slow flood flow through injury to minimize blood loss.
Platelet Phase:
- Platelet adhesion: sticks to exposed collagen at injury site, which activates them
- Platelet aggregation:
Platelets stick together
- Degranulation:
Activated platelets release many factors
Coagulation Phase:
- Forms a blood clot to close large tears and cuts.
The Common pathway (and intrinsic and extrinsic) for Coagulation
Factor X produces Prothrombinase which converts prothrombin to thrombin. Thrombin then converts fibrinogen to fibrin which seals the vessel.
The Intrinsic pathway starts when a factor in the PLASMA contacts exposed collagen
The extrinsic pathway starts when the DAMAGED TISSUE releases factors.
Both ultimately result in the activation of Factor X.
Why is Ca2+ and Vitamin K important in Coagulation?
Ca2+ is required in both the Extrinsic and Intrinsic pathways which both eventually lead to the common pathway and coagulation occurring.
Vitamin K is used to make 4 of the proteins needed to coagulate blood including Prothrombin
Chemicals released by Platelets (4)
ADP: Promotes Platelet aggregation and degranulation
Serotonin: Promotes vasoconstriction
Calcium: aids in efficient coagulation
PDGF: promotes vessel repair
