Brainscape's Knowledge GenomeTM

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


See full index

Phase 1 Medicine > Week 3 - Blood and Haemostasis > Flashcards

Week 3 - Blood and Haemostasis Flashcards

1
Q

What is another word for red blood cells

A

Erythrocytes

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

Shape of RBCs

A

Biconcave discs

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

What is different about erythrocyte cell structure

A

Lacking organelle such as nucleus, mitochondria, ribosomes etc

They do have a cell membrane however

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

What does blood typing categorise individuals based on

A

Antigens found on the surface of red blood cells

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

3 components of red blood cell antigens

A

Proteins

Glycoproteins

Glycolipids

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

Describe the structure of haemoglobin

A

Tetrameric heterodimer composed of 2 alpha globin chains and 2 beta globin chains which each contain a haem group
(A1+B1) (A2,B2)

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

How is haem connected to the globulin chain

A

Histidine

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

Reversible binding occurs between oxygen and which atom, that composes haem?

A

Fe2+

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

Which secondary protein structures support the haem group?

A

Alpha helices

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

During oxygenation and deoxygenation of haemoglobin what structural change occurs?

A

Allosteric conformational change (change in protein structure due to binding of a molecule at an allosteric site)

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

Describe how cooperative binding affects oxygenation of haemoglobin

A

As oxygen binds to one of the haem groups, the affinity that haem has for bonding of subsequent oxygen molecules increases

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

Haemoglobin develops where 2-6 weeks after fertilisation?

A

Yolk sac of embryo

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

Haemoglobin develops where 6-30 weeks after fertilisation?

A

In the liver/spleen/(lymph nodes)

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

Haemoglobin develops where 30 weeks after fertilisation?

A

Bone marrow

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

Describe the composition of haemoglobin

A

97% HbA (adult haemoglobin)
1% HbF (fetal haemoglobin)
2% HbA2 (minor adult haemoglobin)

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

How many molecules of oxygen bind to each molecule of haemoglobin

A

4

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

2 roles of haemoglobin

A

Carries oxygen from the lungs to the peripheral tissues AND carries carbon dioxide back from peripheral tissues to the lungs

Has a buffering function (i.e keeps pH within erythrocyte stable)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the approximate lifespan of erythrocytes

A

120 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What happens to erythrocytes at the end of their lifespan

A

They are targeted for phagocytosis by the macrophages of the reticuloendothelial system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the reaction that occurs when erythrocytes catalyse reaction between water and carbon dixoide

A

Carbon dioxide + water –> carbonic acid

CO2 + H2O –> H2CO3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the hormone that triggers erythrocyte production

A

Erythropoietin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Describe the composition of the blood and give percentages

A

Plasmin (55%) -
* Amino acids
* Electrocytes
* Gases
* Nitrogenous waste
* Nutrients – fat and glucose particles
* Proteins – albumin, globulins, enzymes, clotting factors like fibrinogen

Buffy coat (<1%) -
* Leukocytes
* Thrombocytes

Erythrocytes (45%)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

5 stages to blood clotting mechanism

A
  1. Vasoconstriction
  2. Formation of platelet plug
  3. Formation of blood clot
  4. Eventual growth of fibrous tissue in the blood clot to close the hole permanently
  5. Clot lysis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Describe the mechanism of platelet plug formation

A

Platelets contact exposed collagen on vascular wall, swell and produce pseudopodial projections

Swelling causes release of active factors causing them to become sticky and adhere to collagen and Von Willebrand factor

Willebrand factor leaves circulation and enters tissue causing production of ADP and activated thromboxane

ADP and activated thromboxane attact and activate nearby platelets which adhere to the original activated platelets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Where is thromboxane produced

A

In enzymes found in the platelets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Is the intrinsic or extrinsic pathway faster?

A

Extrinsic is faster

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What initiates the extrinsic pathway

A

Blood vessel tissue trauma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What initiates the intrinsic pathway

A

Activated blood platelets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the common product of the intrinsic and extrinsic pathway

A

Prothrombin activator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

How long until blood clotting starts after major trauma

A

15-20 seconds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How long until blood clotting starts after minor trauma

A

1-2 minutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Where is prothrombin produced

A

Continually in the liver

33
Q

Which vitamin is required for production of prothrombin

A

Vitamin K

34
Q

What is the first structural change thrombin makes to fibrinogen

A

It removes 4 low molecular weight peptides forming a fibrin monomer

35
Q

What does fibrin-stabilising factor do

A

It creates covalent bonds between the fibrin monomers as well as cross linkages between adjacent fibrin fibres

36
Q

Which factors cause the cross linking of adjacent fibrin strands

A

Factor VIIIa

37
Q

Once the blood clot is formed what molecules does it trap

A

Red blood cells

Plasma

Platelets

38
Q

Other than to other fibrin polymers, where else do fibrin fibres adhere to

A

Damaged surfaces of blood vessels

39
Q

Which factor causes the conversion of plasminogen to plasmin

A

tPA

40
Q

What causes clot lysis

A

Plasmin

41
Q

Once clot has been produced, what further tightens the damaged perforation

A

The blood clot expresses most of its fluid within 20-60 minutes

42
Q

What is the name of the fluid that is expressed from the blood clot and how does this differ from plasma

A

Serum - lacks fibrinogen and other clotting factors

43
Q

Describe the positive feedback action of thrombin

A

Further breaks down prothrombin to produce more thrombin

Intrinsic and extrinsic pathways are further stimulated

This positive feedback continues until blood leakage seizes

44
Q

Describe the action of heparin

A

ANTICOAGULANT
Enhances the natural effect of antithrombin

45
Q

Describe the action of antithrombin

A

ANTICOAGULANT

Natural anticoagulant found in the liver that inhibits thrombin, Xa and IXa.

46
Q

Describe the action of low-molecular-weight-heparin

A

Chemically splits heparin into pieces about 1/3 of original size. There are fewer side effects and more predicable results when compared to heparin

47
Q

Describe the mechanism of warfarin

A

A vitamin K antagonist. Works since vitamin K is required to produce a lot of clotting factors. Takes a few days to work since residual factors must be cleared first.

48
Q

What are drugs that target specific factors called

A

Direct oral anticoagulants

49
Q

Name 2 drugs that prevent the breaking up of blood clots

A

Transexamic acid

Aprotinin

50
Q

How does transexamic acid work

A

It inhibits the activation of plasminogen to plasmin as a non-competitive inhibitor

51
Q

How does aprotinin work

A

Inhibits plasmin alongside. other enzymes such as trypsin and chemotrypsin

52
Q

What is the name for drugs that prevent the breaking down of blood clots

A

Antifibrinolytic drugs

53
Q

Which test is a measure of the time it takes for fibrin to form via the extrinsic pathway

A

Prothrombin time (PT)

54
Q

Which test is a measure of time it takes for fibrin to form via the intrinsic pathway

A

Activated partial thromboplastin time

55
Q

What is a normal PT

A

9-12 seconds

56
Q

What is a normal APTT

A

23-38 seconds

57
Q

Which factor is affected in haemophilia A

A

VIII

58
Q

Which factor is affected in haemophilia B

A

IX

59
Q

Why do patients with Von Willebrand disease have lots of bruises/excessive bleeding

A

Von Willebrand factor is required for platelets to stick together - patients with the disease have low levels of VW factor

60
Q

Which cell do platelets originate from

A

Megakaryocytes

61
Q

Which cells eliminate platelets

A

Macrophage

62
Q

Which molecules in platelets are required for formation of projections

A

Actin and myosin

63
Q

What causes platelets to adhere to damaged sections of vessel walls and not normal endothelium

A

Glycoprotein

64
Q

What do you call the process of blood cell formation

A

Haematopoiesis

65
Q
A
66
Q

What is extra-medullary haematopoiesis

A

production of blood cells in the liver, lymph node and spleen

67
Q

What are progenitor cells called that are involved in extra-medullary haematopoiesis

A

Common lymphoid progenitor

68
Q

What are the progenitor cells called that are involved in medullary haematopoiesis

A

Common myeloid progenitor

69
Q

Where does the majority of haematopoiesis happen during fetal development

A

In the liver and spleen

70
Q
A
71
Q

What causes an increase in blood cells in the liver/spleen after birth?

A

Infection or onset of a disease since they have to work extra hard to produce immune cells for example

72
Q

What is a clinical sign of infection relating to extra medullary haematopoesis

A

Swelling of liver/spleen/lymph nodes

73
Q

Haematopoiesis is regulated by which what, and what are two examples of these?

A

Cytokines
- interleukins (IL)
- stimulating factors

74
Q

What do cytokines control in the context of haematopoiesis

A

Proliferation

Differentiation

Death

(of progenitor cells)

75
Q

What initiates the production of blood cells

A

Progenitor cells develop surface receptors for a specific stimulating factor and when stimulating factors bind, they lose their potency and remain committed to producing that certain cell type

76
Q

3 examples of cytokines that influence haematopoiesis

A

Erythropoietin (EP) - erythrocyte production

Colony-stimulating factors (CSFs) - granulocyte and macrophage production

Thrombopoietin (TPO) - megakaryocyte production which produce platelets

77
Q

Why is sodium citrate used in blood transfusion

A

Chelates calcium ions, preventing blood clot formation for some time. Sodium citrate is easily metabolised by the body as well, so calcium ions are made available in vivo

78
Q

What is an example of a Zymogen

A

Fibrinogen

79
Q
A

Phase 1 Medicine (37 decks)

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