Blood

Question 1

what are anticoagulants?

Answer 1

compounds that prevent blood clotting

Question 2

what is a clotting factor?

Answer 2

enzymes/proteins that are required for clot formation

Question 3

coagulation

Answer 3

the conversion of liquid blood to a gel like solid

Question 4

homeostasis

Answer 4

the stopping of bleeding, blood clotting is only a part of homeostasis

Question 5

platelets

Answer 5

very small acellular particles, small pieces budded from special cells, found in whole blood which when activated play an important role in clotting

Question 6

proteases

Answer 6

an enzyme which cleaves peptide bonds in their substrates

Question 7

proteolysis

Answer 7

cleavage of peptide bonds in proteins

Question 8

thrombin

Answer 8

an enzyme (clotting factor) which forms clots

Question 9

thrombosis

Answer 9

formation of dangerous clots

Question 10

thrombus

Answer 10

a blood clot (generally in medicine a clot which occurs in a disease process eg formation of a clot where it is not wanted)

Question 11

what are the 3 phases of haemostasis

Answer 11

vasoconstriction, formation of a platelet plug, coagulation

Question 12

what is used to prevent coagulation when blood is stored?

Answer 12

sodium citrate

Question 13

what initiates the extrinsic pathway

Answer 13

tissue factor released by damaged cell (can be tested by PT)

Question 14

what initiates the intrinsic pathway?

Answer 14

activated platelets (can be tested by APPT)

Question 15

what is fibrinolysis?

Answer 15

the process by which the clot is removed, done by a protein called plasmin

Question 16

where is plasminogen synthesised

Answer 16

in the liver and then circulates in the plasma

Question 17

how does plasminogen work?

Answer 17

it becomes trapped in a clot as it forms, it is activated by a serine protease called tissue plasminogen activator (tPA). tPA converts plasminogen to plasmin which then breaks down the fibrin mesh

Question 18

what does thrombin do?

Answer 18

after being turned from inactive thrombin to active prothrombin it facilitates the formation of insoluble fibrin from soluble fibrinogen which leads to the gel like consistency of the clot

Question 19

how does the clot form?

Answer 19

a lattice of fibrin strands forms which traps blood cells to create a soft clot then crosslinks form which creates a more stable hard clot

Question 20

what gets rid of the clot?

Answer 20

plasmin

Question 21

what does APTT stand for?

Answer 21

activated partial thromboplastin clotting time

Question 22

what is APTT?

Answer 22

A clinical test used to measure and evaluate all the clotting factors in the intrinsic and extrinsic pathways of the clotting cascade

Question 23

how is the extrinsic pathway tested for?

Answer 23

PT (prothrombin time)

Question 24

how is the intrinsic pathway tested for?

Answer 24

APTT (activated partial thromboplastin clotting time)

Question 25

where do the pathways converge?

Answer 25

at coagulation factor X to Xa. (clotting factor 10) prothrombin to thrombin

Question 26

where in the coagulation cascade is there a positive feedback system?

Answer 26

at thrombin as thrombin stimulates its own formation.

Question 27

what is normal plasma?

Answer 27

plasma prepared from a bulk sample of plasmas obtained from at least 100 donors.

Question 28

what is EDTA?

Answer 28

an effective calcium ion chelator

Question 29

when does clotting occur?

Answer 29

when soluble fibrinogen is converted to insoluble fibrin

Question 29

what cell releases heparin?

Answer 29

mast cells. it is also an anticoagulant that has Many clinical uses.

Question 30

what is fibrinolysis?

Answer 30

process by which a clot is removed.

Question 31

where is plasminogen synthesised?

Answer 31

in the liver and then circulates in the plasma

Question 32

what factor is released in the extrinsic pathway when there is damage to the vessel wall?

Answer 32

endothelial cells will release factor III

Question 33

what happens when the intrinsic pathway is initiated?

Answer 33

blood is exposed to collagen

Question 34

where do the platelets stick to?

Answer 34

the collagen, they swell up, become irregular in shape and release granules

Question 35

how is plasminogen activated?

Answer 35

by a serine protease called tissue plasminogen activator (tPA). tPA converts plasminogen to plasmin

Question 36

What does the liver need to produce some clotting factors?

Answer 36

Vitamin K

Question 37

What does warfarin do?

Answer 37

Blocks some of the enzymes that produce vitamin K to produce clotting factos. Therefor works as a vitamin K antagonist

Question 38

What type of cell would be found in the buffy coat?

Answer 38

Platelets

Question 39

What is in the buffy coat?

Answer 39

Lymphocytes, monocytes, granulocytes, platelets