Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

pathology > hemostasis > Flashcards

hemostasis Flashcards

1
Q

define hemostasis

A

normal state of balance maintained in the blood to control hemorrhage and inhibit thrombosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the temporary hemostatic plug made by?

A

platelets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What do platelets do in controlling hemorrhage?

A
  1. adhere to side of vessel
  2. activated
  3. aggregation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what does protein expressed is required for adherence?

A

von Willebrand factor (vWF)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what receptor do platelets bind to vWF on the surface?

A

glycoprotein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

how do platelets get activated?

A

by exposure to subendothelial collagen and thrombin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

how do activated platelets assume a different shape to better clump and interact with one another?

A

pseudopods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

when platelets are activated, what receptor on the surface forms and why?

A

GPIIb:GPIIIa, and it forms the essential ligand to hold platelets together, with the help of fibrin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is aggregation?

A

When proteins found in the blood (especially fibrinogen), contact the glycoprotein receptor (GPIIb:GPIIIa), they get sticky

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what two hormones get released to activate more platelet activation?

A

Prostaglandin H2 and Thromboxane A2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what fuels the platelet activation/aggregation fire when platelet contents are released?

A

ADP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

____________ is facilitated through the platelet membrane exposure of certain enzymes and cofactors essential for the clotting cascade

A

coagulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what starts contracting to solidify the temporary plug?

A

platelet actinomysin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

when is the permanent hemostatic plug formed?

A

when the clotting cascade gets activated and the platelet plug gets made more permanent by the glue known as fibrin. This fibrin clot forms the needed bulk and anchoring mechanism.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

go in order of what happens to form the permanent hemostatic plug

A

clotting cascade -> formation of thrombin -> fibrinogen -> fibrin -> permanent hemostatic plug

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are the two pathways of the clotting cascade?

A

intrinsic and extrinsic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

how does the intrinsic factor start?

A

Hageman factor (factor XII) contacts endothelial surface

18
Q

how does the extrinsic factor start?

A

when substances contact factor VII

19
Q

which pathway is faster and gets put into action when damage is deeper?

A

extrinsic

20
Q

An anticoagulant used for collecting blood for CBC (complete blood count) is EDTA. How does this substance keep the clotting cascade from occurring?

A

Calcium ions are needed in many parts of the cascade. EDTA binds calcium, making it unavailable. No calcium, no clot.

21
Q

When clotting is measured in the laboratory, is it the extrinsic or intrinsic system that is being measured, and why?

A

intrinsic

The intrinsic system is activated by exposure to collagen or any negatively charged surface whereas the extrinsic system requires tissue factor, which is not present in a glass tube.

22
Q

Surgical trauma acts via which pathway predominantly?

A

Tissue factor binds rapidly to Factor VII, starting the extrinsic pathway on a tear.

23
Q

Many rodenticides act by tying up Vitamin K so that the rodents bleed to death. Which factors are involved?

A

Vitamin K is a necessary cofactor in the carboxylation of glutamate residues which are necessary for functional activity in Factors VII, IX, X and prothrombin. Without Vitamin K, there is massive hemorrhage because none of these factors are functional. Unfortunately, when dogs get into rat poison, their Vit K gets tied up also, and the result is death due to hemorrhage

24
Q

true or false: factors present in blood are usually active

A

false: inactive

25
Q

true or false: in order for clotting to occur, each factor must be active

A

true

26
Q

What keeps clotting from happening all the time?

A
  1. Activated clotting factors get removed from the circulation as they pass through the liver.
  2. There are quite a few inhibitors present in the plasma.
26
Q

how does the extrinsic pathway inhibitor (EPI) or TFPI prevent coagulation from happening?

A

binds with Xa and then this complex binds to VIIa/tissue factor and inactivates so the extrinsic pathway can’t go nowhere

27
Q

what does antithrombin III inhibit the action of?

A

thrombin, Xa, and IXa

28
Q

how does heparin prevent clotting?

A

it converts antithrombin III from a slow to an instantaneous inhibitor of thrombin, Xa and IXa

29
Q

thrombin binds to thrombomodulin on endothelial cells and so activates Protein C. How does that inhibit coagulation?

A

Protein C inactivates Va and VIIIa and speeds up fibrinolysis.

30
Q

what is the most important molecule in fibrinolysis?

A

plasmin

31
Q

what does plasmin do?

A

break down fibrin

32
Q

how is plasmin formed?

A

from activation of plasminogen

33
Q

the amount of plasmin there is depends on what?

A
  • plasminogen activators, many come from endothelium
  • streptokinase, made by bacteria, is a powerful plasminogen activator and used to therapeutically break up clots
34
Q

what categories are hemostatic disorders broken into?

A
  • failure of primary hemostasis, which means something wrong with the platelets
  • failure of secondary hemostasis, which means something wrong with clotting factors
35
Q

true or false: conditions can be both inherited or acquired

A

true

36
Q

dog has recurrent mucosal surface bleeds. we see ecchymotic hemorrhages on the conjunctiva. What is the most common inherited bleeding disorder in dogs?

A

Von Willebrand’s disease.

need VWF to bind the platelet to the damaged endothelium. Without this, platelets don’t stick. That makes it a primary hemostatic defect

37
Q

hemophilia is an example of what category of hemostatic disorder?

A

secondary hemostasis

38
Q

what pathway do we want to measure to test hemophilia? and what test can be ran?

A

intrinsic pathway

partial thromboplastin time (PTT)
- partial because does not contain tissue factor

39
Q

what test measures the extrinsic pathway of hemophilia?

A

Prothrombin Time (PT), which measures the EXTRINSIC pathway.

40
Q

what is consumptive coagulopathy?

A

all of the platelets and clotting factors get used up so fast that the animal cannot control bleeding.

41
Q

dog had amyloidosis, in the kidney, amyloid affects the glomeruli and makes them excessively leaky. How does that impact hemostasis?

A

If the glomerulus becomes leaky, protein is lost to the outside of the body as it traverses the capillaries in the glomerular filtration apparatus.

Antithrombin III is one of the first proteins to be lost.

Without antithrombin III, there is too much thrombin around and fibrinogen is readily converted to fibrin in many places where it shoulda just stayed as fibrinogen. Instant clots and way too many of them

pathology (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions