intro to haematology

Question 1

what is blood?

Answer 1

connective tissue

Question 2

how much blood does an average adult have?

Answer 2

4-6 litres

Question 3

what does the amount of blood in a person depend on?

Answer 3

the size of the person
concentration of ions
gender
amount of adipose tissue

Question 4

what is Erythrocytes?

Answer 4

for transport of oxygen
no nucleus
biconcave shape
has pigment called haemoglobin
contains Erythropoietin which regulates production of red blood cells

Question 5

what are the types of white blood cells-leucocytes?

Answer 5

Granulocytes
Agranulocytes

Question 6

what is Leukocytosis?

Answer 6

high white blood cell count because of infection

Question 7

what is Leukopenia?

Answer 7

low WBC because of viral infection and other infections

Question 8

what are platalets?

Answer 8

fragments of cell called thrombocytes
used in clotting of blood
have receptors to bind to collagen
have ADP and other that trigger blood clotting

Question 9

what is plasma?

Answer 9

liquid part of blood, mostly water

Question 10

what does plasma contain?

Answer 10

nutrients
proteins
gases
electrolytes
waste products

Question 11

what are the role of proteins in plasma?

Answer 11

bind to hormones and drugs and control volume regulation

Question 12

what type of proteins are in plasma?

Answer 12

Albumins
Globulins-for transportation and immune defense
Fibrinogen-for blood clotting

Question 13

what is Haematopoiesis?

Answer 13

generates blood cells from same stem cell
found in bone marrow of adults
regulated by hormones and cytokines

Question 14

what is Haemostasis?

Answer 14

‘the physiological control of bleeding’
localized vasoconstriction happens at site of injury

Question 15

blood clot?

Answer 15

prevent blood loss, allows healing
clotting remains localized

Question 16

how is blood clot formed?

Answer 16

forms at site of injury by several, temporally overlapping stages

Question 17

what are the stages of blood clot?

Answer 17

primary and secondary haemostasis

Question 18

what is Primary haemostasis?

Answer 18

platelet plug formation

Question 19

what is secondary haemostasis?

Answer 19

clotting cascade

Question 20

what occurs after vasoconstriction?

Answer 20

primary haemostasis

Question 21

what happens during primary haemostasis?

Answer 21

formation of a primary haemostatic plug that contain aggregated platelets

Question 22

how does a primary haemostatic plug form?

Answer 22

platelets are activated and the site of action is the subendothelial matrix, this happens by having activated platelets to change shape and releasing secretory granule contents
the secretory granules cause other platelets to become involved

Question 23

what is platelet adhesion mediated by?

Answer 23

von Willebrand factor (vWF)
Platelet glycoprotein VI (GPVI)
GPIb:vWF:collagen and GPVI:collagen needed for initiation of primary haemostasis

Question 24

what happens during platelet aggregation/

Answer 24

fibrinogen cross-links platelets to each other

Question 25

what is platelet recruitments and aggregation medicated by?

Answer 25

ADP and TxA2

Question 26

what happens during secondary haemostasis?

Answer 26

tissue factor initiates coagulation cascade which is a sequence of enzymatic activity then thrombin activated

Question 27

what are the two functions of thrombin?

Answer 27

converts soluble fibrinogen to an insoluble fibrin polymer causes more platelet recruitment and activation

Question 28

why is haemostasis highly regulated at the site of injury?

Answer 28

to keep the lumen patent

Question 29

what are the five mechanisms of the endothelium around the injury and what do they do?

Answer 29

Prostacyclin- stop platelet aggregation and adhesion Heparin and antithrombin III- inhibitors of thrombin Proteins C and S-'limits activation factors of factors V and VIII in clotting cascade' Tissue factor pathway inhibitor- reduces action of tissue factor Tissue-type plasminogen activator-converts plasminogen to plasmin which breaks down fibrin

Question 30

what is thrombosis?

Answer 30

extension of haemostasis but less controlled pathologic clot called thrombus

Question 31

what are the three major properties of thrombosis?

Answer 31

endothelial injury, abnormal blood flow, and hypercoagulability known as Virchow’s triad

Question 32

what is endothelial injury?

Answer 32

thrombus formation in heart and the arterial circulation

Question 33

what are the three classes of thrombus formation prevention?

Answer 33

antiplatelet agents anticoagulants thrombolytic agents also surgical inventions like stents

Question 34

how are blood types told apart?

Answer 34

antigens on the surface of the blood cells and antibodies in plasma

Question 35

why is it dangerous for a Rh-negative person to receive Rh-positive blood?

Answer 35

antibodies bind to cells and agglutination occurs