introduction to haematology Flashcards
composition of blood
red blood cells, white blood cells, platelets, plasma
what is haematopoiesis
generation of blood cells
what is haemostasis
control of clot formation
what are platelets
cell fragments found in bloodstream, has receptors to bind to factors that help clotting
what is plasma
fluid part of blood
amount of blood a person has depends on
size, concentration of ions, amount of adipose tissue, females usually have less
another name for red blood cells
erthrocytes
another name for white blood cells
leukocytes
what is hematocrit
percentage of red blood cells
what do blood cells do
transport oxygen around the body
shape of red blood cells
biconcave shape, no nucleus
what is haemoglobin and what are the 3 types and what they do
pigment in rbc
oxyhaemoglobin- carries oxygen, bright red
deoxyhaemoglobin- doesnt carry oxygen, darker red
carboxyhaemoglobin- carries carbon dioxide
what causes anemia
low rbc count
what regulates production of red blood cells
erythropoietin (EPO)
types of white blood cells
granulocytes, agranulocytes
composition of granulocytes and their functions
neutrophils- destory bacteria, virus and toxins in bloodstream
eosinophils- gets rid of parasitic infections
basophils- controls inflammation and allergic reactions
what do basophils do
controls inflammation and allergic reactions
what do neutrophils do
destroy bacteria, viruses and toxins in the blood
what do eosinophils do
get rid of parasitic infections
composition of agranulocytes and what they do
monocytes- destroy bacteria, viruses and toxins in the blood
lymphocytes- provide immunity for the body (production of antibodies, cell killing etc.)
what do monocytes do
destroy bacteria, viruses and toxins that enter the blood
what do lymphocytes do
provide immunity for the body like producing antibodies and killing cells
difference between granulocytes and agranulocytes
granulocytes exist in the cytoplasm in forms of granules and have 4 lobes and agranulocytes have no granules and are single lobed
what is caused when a patient has elevated wbc count
leukocytosis
what is caused when someone has low wbc count
leukopenia
what is leukocytosis and what can cause it
elevated white blood cell count, due to infection
what is leukopenia and what can cause it
low white blood cell count, due to viral infections
another name for platelets
thrombocytes
composition of plasma and some examples
water
proteins- albumin, globulin
fibrinogen- blood clotting
nutrients- amino acids, glucose, nucleotides, lipid
gas- oxygen, carbon dioxide, nitrogen
electrolytes
waste products
what do the protein in blood plasma do
bind/transport hormones and drugs, involved in volume regulation
what is haematopoiesis
generation of blood cells from a common stem cell,
where does haematopoiesis occur in adults and fetuses
bone marrow of adults
liver and spleen in fetus
what regulates haematopoiesis
hormones and cytokines
-erythropoietin, granulocyte
what is haemostasis
physiological control of bleeding
why must an injured blood vessel clot
prevent blood loss and allow healing
why must clot formation remain localised
prevent widespread clotting with intact vessels
what are the stages of haemostasis
primary- platelet plug formation
secondary- clotting cascade
what happens before primary haemostasis occurs
localised vasoconstriction
process of haemostasis
- constriction of blood vessel (vasoconstriction)
- formation of temporary platelet plug
- clotting cascade
- formation of fibrin plug
role of platelets in haemostasis
-adhere to exposed sub endothelial matric
-activation of platelets involve change in shape and releasing secretory granule contents
-secreted granule substance recruit other more platelets to adhere to site of injury
what is platelet adhesion mediated by
vWF (von willebrand factor)- large protein secreted by activated platelets and injured endothelium and binds both to surface receptors on platelets and exposed collagen
platelet glycoprotein VI (GPVI)- interacts with collagen in exposed vessel wall
what is required for the initiation of primary haemostasis
GPIV and vWF and collagen interaction
how are more platelets activated
activated platelets change shape and release granules to activate more platelets
what regulates platelet recruitment and aggregation
the release of soluble platelet factors like ADP and thromboxane
ADP- makes platelets become sticky and adhere to each other
thromboxane- vasoconstrictor
another name for secondary heamostasis
coagulation cascade
what initiates coagulation cascade
tissue factor complexes with coagulation factors
what is the result of coagulation cascade
activation of thrombin
function of thrombin in haemostasis
-converts soluble fibrinogen to insoluble fibrin polymer that forms matrix of the clot
-induces more platelet recruitment and activation
mechanisms the endothelium around the injured area participates in to stop haemostasis
prostacyclin - blocks platelet aggregation and adhesion
heparin and antithrombin- inhibits thrombin
protein C and S- blocks activation factors in clotting cascade
tissue factor pathway inhibitor- blocks/limits tissue factor action
tissue type plasminogen activator- converts plasminogen to plasmin which brakes down fibrin
what is hypercoagulability
increased tendency of blood to thrombose, abnormally heightened coagulation response to vascular injury
causes of thrombosis
endothelial injury, abnormal blood flow, hypercoagulability
possible causes of endothelial injury
changes in shear stress associated with hypertension, hyperlipidaemia, elevated blood glucose, traumatic vascular injury
what is thrombosis
local coagulation/clotting of blood, pathological extension of haemostasis
what can cause hypercaogulability
genetic or acquired disorders
name the 3 type of drugs that prevent/reverse thrombus formation and give examples
antiplatelet agents- ADP receptor inhibitors, cyclooxygenase inhibitors, antagonists of GP
anticoagulants- warfarin, heparin
thrombolytic agents- streptokinase, recombinant tissue plasminogen activator
how are blood types differenciated
distinguished by the antigens on surface of red blood cells and antibodies in plasma
what is agglutination and how does it work
clumping of red blood cells, antigens on rbc surface bind to antibodies in plasma
why is it important to know blood type
transfusions
name the 4 blood groups
A, B, AB, O
precise grouping of blood type depends on
-presence/absence of 2 antigens (A or B on the surface)
-respective antibodies in the plasma (anti-A or anti-B)
different combinations of these give different groups
why are transfusions done
patient suffered significant blood loss or has conditions like anaemia
what happens to donated blood
its separated into red blood cells and plasma
