Week 1 Flashcards
What are the components of blood?
Erythrocytes, leukocytes + platelets
What are the main functions of blood?
Transportation of nutrients, gases + immune reponse cells, regulation of homeostasis
What is the function of albumin?
Regulation of osmotic pressure + has a buffering capacity
What is the function of alobulin (globulin)?
Liver function, blood clotting + fighting infection
What is the function of fibrinogen?
Main viscosity composition, major role in blood clot formation (coagulation)
What is thrombocytosis + what are some key clinical features of thrombocytosis?
Increased platelet count
Dizziness/lightheadedness, weakness, numbness
What is thrombocytopenia + what are some key clinical features?
Low platelet count
Easy bruising, superficial bleeding, prolonged bleeding time, bleeding from gums/nose, blood in urine/stools
What is the mechanism of action for platelets?
Adhesion, aggregation + aggulation
Platelets become activated and are sticky, they aggregate together and aggulate to form clumps - platelet plug
What is the importance of the structure of RBCs?
No nucleus + shape increases surface area to carry more oxygen
Strong + flexible membrane to allow them to move through small capillaries
Describe the function of RBCs
Main function - use haemoglobin to carry oxygen molecules from the lungs to tissues and remove CO2 from tissues and take them to the lungs to be expired
Describe the stages of erythropoiesis
Pluripoptent stem cell -> CFU(GEMM) -> BFU(E) -> hemocytoblast (deeply basophilic, largest in size) -> proerythroblast (scanty) -> basophilic erythroblast -> polychromatic erythroblast (nucleus becomes condense, Hb appears, slightly acidophilic)-> orthochromatic erythroblast (increased Hb, nucleus is small, completely acidophilic) -> reticulocyte (no nucleus, immature RBC)
Describe the role of neutrophils + key features
Phagocytose bacteria + debris
Nuclear lobe number increases with age
Describe the role of eosinophils
They react to foreign proteins that have been marked by precursor cells
Outline the function of basophils
Ability to detect aand destroy early cancer cells
Release histamine during an allergic reaction
Also release heparin + hyaluronic acid
What is the role of monocytes?
Mononucleated
Play a role in inflammatory + antiinflammatory responses
What is the function of lymphocytes? What is the difference between T lymphocytes + B lymphocytes?
Humoral + cell-mediated immunity
T cells - kill infected host cells, activate other immune cells, produce cytokines, regulate immune cells
B cells - antigen presentation, costimulation, cytokine production
Outline the steps in leukopoiesis
Myeoloblast -> myelomonoblast -> promonocytes -> monocytes (blood) -> macrophage (tissue)
Myeloblast -> promyelocyte -> band neutrophil (immature) -> neutrophil
What are the important functions of platelets?
Platelets are the first clotting line
They form a platelet plug and cause the clotting cascade
What activates platets?
Subendothelial collagen of blood vessels
ThromboxaneA2 binds to rece[tors to trigger aggregation + clot formation
Where are blood cells formed in a foetus?
Thymus (mediastinum)
Where are blood cells formed in adults?
Red bone marrow
What is the role of erythropoietin in erythropoiesis
Erythropoietin is a glycoprotein - acts directly on the pluripotent stem cells to encourage differentiation + promotes Hb synthesis by increasing globin synthesis
List four factors which affect haematopoiesis
Erythropoietin
Cytokines
Growth factors
PTH
What is the location of haematopoiesis in weeks 3-10 of gestation?
Yolk sac
