Hubs - Blood System

Front 1

describe structure of platelets and there other name

Back 1

also called thrombocytes; they are an irregular spindle shaped that will assume other shapes on contact.

-about 2-4um

Front 2

Platelet formation

Back 2

formed by process called Thrombopoietin. originate from one cell but as the differnetiate more they get larger, as stimulated by hormones they then break off to form smaller parts called platelets.

Front 3

stages of blood coagulation..

Back 3

Stage 1:

a) constriction of blood vessels, immediate response to reduce blood flow.

b)formation of platelet plug (trigger for later coagulation process).

stage 2 and 3:

formation of plug which requires platelets. clotting cascade.

Front 4

stage 1 part a) of coagulation process:

Back 4

-exposure of underlying collagen layer, stimulates activation for platelets to adhere to one another.

-this triggers release of mediators (ADP and Thromboaxne A2 ) from epithelium; this stimulates more aggregation of platelets and vasoconstriction of blood vessels.

Front 5

stage 1 part b) of coagulation process:

Back 5

-chemical reactions take place on surface of platelet to activate prothrombin; can follow Intrinsic pathway (everything in the blood) or the extrinsic pathway (cellular element- in the tissue).

Front 6

Intrinsic activation pathway of prothrombin

Back 6

activation due to contact with broken endothelium layer. factor xii --> factor x

Front 7

Extrinsic activation pathway of prothrombin

Back 7

activation due to detection of tissue damage. tissue factor--> factor vii --> factor x

Front 8

once factor x is activated then...

Back 8

factor x will activate prothrombin activator, this will bind with calcium to active prothrombin.

-prothrombin activates thrombin that activates fibrinogen, which will activate fibrin .

Front 9

components opposing clot formation:

Back 9

-endothelium is smooth and secrets prostacyclin which prevent platelet aggregation from occurring all the time.

-Nitric acid is also secreted that causes vasodialtion

-tissue factor pathway inhibitor released from endothelium stops extrinsic pathway.

-antithrombins (Heparin) inhibit thrombin.

-Coumadin impairs liver use of Vit K

-Asprin also impairs platelet aggregation.

Front 10

What is Fibronolysis?

Back 10

process of breaking down blood clot, occurs at the same time as clot formation.

-clot is made using Plasminogen. this is the pre-enzyme for plasmin which will breakdown the fibre of the blood clot so that blood will flow again. (plasminogen is activated by tissue plasminogen activator).

Front 11

Blood Groups:

Group A;

Group B;

Group AB;

Group O;

Back 11

A; antigen A, Antibody B

B; antigen B, Antibody B

AB; antigen A and B, no antibody

O; no antigen, antibody A and B

Front 12

blood group AB is a?

Back 12

universal receiver

Front 13

Blood group O is a ?

Back 13

universal donor

Front 14

Rhesus Positive means ...?

Back 14

you have an D antigen, about 85% of the population are positive.

Front 15

why does the Rhesus system cause problems with pregnancy?

Back 15

it involves igG antibodies that are able to cross the placenta. if the mother is -ve and baby +ve then the D antigen will move across the placenta and the mother will start to produce (at first) igM antibodies, so the baby will not be harmed. however for the second pregnancy if baby is once again +ve , antibodies are already present so igG will develop that is able to cross the placenta and cause the baby to develop anaemia.