Blood Flashcards

1
Q

Define circulatory shock.

A
Blood vessels are inadequately filled with blood (have lower BP) and blood cannot circulate normally.
Can be due to:
- hypovolemic shock
- vascular shock
- cardiogenic shock
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2
Q

What is hypovolemic shock? How can it be treated?

A

Due to large scale fluid loss (haemorrhage, dehydration).

Treat with replacing fluid (saline drip - replaces volume)
BUT - also need blood transfusion (replace oxygen carrying capacity)

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3
Q

What is vascular shock?

A

Due to large scale vasodilation. May be due to:

  • anaphylactic shock (allergic reaction - large scale relate of histamine - vasodilation)
  • septic shock (toxins released from bacteria which are vasodilators)
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4
Q

What is cariogenic shock? How is it treated?

A

Due to pump failure (heart is insufficient and cannot maintain adequate cardiac output). Due to MI / chronic hypertension

Treat with positive inotropes (e.g., digitalis)

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5
Q

What are the three main roles of blood?

A

Distribution (transport materials, hormone delivery)
Regulation (pH, heat, fluid)
Protection (prevents blood loss, delivers antibodies and WBC)

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6
Q

What % of body weight is blood? What volume?

A

7-8%

5-6 L in 75 kg males (female slightly less)

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7
Q

Why is a cardio vascular system required?

A

Diffusion distance is too large and therefore too slow

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8
Q

Discuss the composition of blood

A

55% plasma (fluid)

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9
Q

Plasma proteins account for ______ of blood plasma.

A

10%

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10
Q

Plasma proteins are produced by the _______.

A

Liver

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11
Q

Plasma contains:

A

Water (90% plasma volume) / ions / salts
Amino acids / proteins (8-10% plasma volume)
Lipids (generally bound to proteins) / CO2
Nitrogen wastes (urea) and hormones

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12
Q

What are three plasma proteins? What %?

A

Albumin 60%
Globulins 35%
Fibrinogen 5%

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13
Q

What is the role of albumin? What percentage?

A

60% of plasma proteins
Potent pH buffer
Carrier protein
Colloid osmotic pressure

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14
Q

What is the role of globulins? What percentage?

A

35% plasma proteins
Carrier protein
Gamma globulins

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15
Q

What is the role of fibrinogen? What percentage?

A

5%

Blood clotting

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16
Q

What are the true and not-true cells?

A

Not true cells = non nucleus = platelets and erythrocytes

True cells = nucleus = leukocytes

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17
Q

What are the formed elements of the blood?

A

Platelets, leukocytes, erythrocytes

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18
Q

Leukocytes can be: _______ or _______.

________ can be _________
________ can be _________

A

Leukocytes can be GRANULOCYTES or AGRANULOCYTES.

Granulocytes can be NEUTROPHILS, EOSINOPHILS, BASOPHILS

Agranulocytes can be LYMPHOCYTES, MONOCYTES

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19
Q

What is the difference between a granulocyte and an agranulocyte?

A

Granules in cytoplasm vs clear cytoplasm

Granulocytes = neutrophils, eosinophils, basophils

Agranulocytes = monocytes, lymphocytes

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20
Q

What is the diameter of a RBC?

A

7.5 um

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21
Q

What is the importance of the shape of a RBC?

A

Biconcave shape - very large SA to volume ratio (increased by 30%)

Decreased distance for CO2 and O2 to diffuse

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22
Q

What is spectrin?

A

A scaffolding protein on the inside surface of a RBC membrane

Maintains the biconcave shape, even when RBCs are deformed when squeezing through capillaries

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23
Q

RBCs are _______ and have no ________

A

Anuclear

Have no mitochondria

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24
Q

Define haematocrit

A

Percentage of blood volume made up by erythrocytes

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25
Q

What are the % haematocrit for males and females?

A
Males = 45%
Females = 43%
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26
Q

What happens to haematocrit during anaemia?

A

Haematocrit may fall to 15%

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27
Q

What happens to haematocrit during polycythaemia? When does it occur?

A

Haematocrit may rise to 75%.

Can be caused by blood doping, EPO, altitude altitude

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28
Q

What happens to haemoatrocrit during dehydration?

IN MCQ!!

A

The plasma volume decreases but the number of RBCs does not change

BUT - plasma volume decreases, so % haematocrit increases

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29
Q

Haemoglobin is a ______ protein.

A

Globin

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30
Q

Adult haemoglobin is made of _____ ________________. 2 ____ and 2 ______.
Each chain has a _____ _____, which contain an ______.

A
Made of 4 polypeptide chains
2 alpha chains
2 beta chains
Heme group
Iron ion
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31
Q

An iron ion can _________.

A

Reversibly bind to 1 oxygen

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32
Q

What is haemoglobin called when oxygen is bound?

A

Oxyhemoglobin

33
Q

What is haemoglobin called when no oxygen is bound?

A

Deoxyhemoglobin

34
Q

How many molecules of oxygen can we carry in Hb? How many RBCs?

A

4 Iron per Hb.
250 million Hb per RBC
1 billion O2 molecules per RBC
We create and destroy 2 million RBCs per second

35
Q

How does foetal haemoglobin differ from adult haemoglobin?

A

2 alpha and 2 gamma (foetus)
vs.
2 alpha and 2 beta chains (adult)

Foetal Hb has higher affinity for O2 than Adult Hb - allows oxygen to diffuse across placenta from adult Hb to foetal Hb

36
Q

What is carbaminohaemoglobin?

A

When CO2 binds to POLYPEPTIDE CHAIN (not Fe)

20% CO2 on polypeptide chain
80% CO2 in plasma

37
Q

Discuss carbon monoxide poisoning.

A

Carboxyhemoglobin - CO binds in place of O2 (binds to Fe) preventing oxygen from binding as Hb has a very high affinity for CO.

38
Q

What is erythropoiesis?

A

The formation of RBC.

39
Q

What is haematopoiesis?

A

Formation of ALL blood cells (not just RBC)

40
Q

Where does haematopoiesis occur?

A

Adults - in red bone marrow of axial skeleton and limb girdles, and epiphyses of humerus and femur.
Foetus - in foetal yolk sac, liver, spleen. By 7 months - red bone marrow is primary haematopoietic area

41
Q

How many RBCs are produced and removed per second?

A

1 - 2 million RBCs per second

42
Q

What releases EPO? What stimulates EPO release?

A

Kidney releases EPO.

Altitude, low Hb, low RBC and testosterone stimulate kidneys to releases EPO

43
Q

Do males or females have a higher haematocrit? Why?

A

Males = 45%. Females = 43%.

Males have more testosterone, which stimulates EPO release, which result in formation of RBC

44
Q

How long do RBCs circulate for?

A

120 days

45
Q

Haemoglobin is made of a ____ and _____ part.

A

Haemoglobin is made of a HEME (IRON) and GLOBIN (POLYPEPTIDE CHAINS) part.

46
Q

How can kidney failure result in anaemia?

A

Kidney failure - lack of EPO production and secretion - decreased production of RBC - decrease oxygen carrying capacity of blood

47
Q

What symptoms does high bilirubin result in?

A

Jaundice

48
Q

The globin portion of haemoglobin is broken down into __________.

A

Amino acids, which are reused.

49
Q

The heme portion of the haemoglobin is broken down into __________.

A

Bilirubin (yellow pigment) and iron (Fe ions)

50
Q

What is bilirubin?

A

Formed from degradation of heme portion of Hb - yellow pigment - not water soluble - secreted in bile - gives urine yellow colour - by products give faeces brown colour

51
Q

Where are ageing RBCs degraded? Why are they degraded?

A

Degraded in the liver and spleen, by macrophages (which recognise and phagocytise aged cells)

Aged cells = cell properties change (cell membrane changes)

52
Q

What are the dietary requirements of erythropoiesis?

A

Amino acids = form polypeptide chain
Lipids = form phospholipid bilayer
Carbohydrates = glycoproteins (antigens on RBCs)
Iron (in heme group)
Vitamin B12 and folic acid = needed for rapid cell division forming RBCs

53
Q

What % of the body’s iron is found in haemoglobin? Where is the rest.

A

65%. The rest is in the liver, spleen and bone marrow.

54
Q

What does iron bind to?

A

In tissues = binds to protein-iron complexes (Ferritin)

In circulation = binds to transport protein (transferrin)

55
Q

What is an anaemia?

A

Insufficient oxygen carrying capacity of blood due to insufficient RBCs and/or insufficient Hb.

56
Q

What are symptoms of anaemia?

A

Fatigue, breathlessness, chills, pale

57
Q

What types of anaemia can be caused by insufficient RBCs?

A

Hemorrhagic anaemia
Haemolytic anaemia
Aplastic anaemia

58
Q

What is haemorrhagic anaemia?

A

Insufficient RBCs due to excess blood loss. Can be due to peptic ulcers (bleeding into stomach/SI)

59
Q

What is haemolytic anaemia?

A

Insufficient RBCs due to premature breakdown of blood cells. Can be due to mismatched blood, sickle cell anaemia

60
Q

What is aplastic anaemia?

A

Caused by radiation and chemicals (chemotherapy).
This targets rapidly dividing cells - BUT also stem cells in bone barrow - disrupts haematopoiesis (formation of RBC, WBC, platelets).
Low WBC = prone to infection
Low platelets = prone to bleeding
Low RBC = anaemic

61
Q

What types of anaemia can be caused by insufficient Hb?

A

Iron deficiency

Pernicious anaemia

62
Q

What does iron deficiency do? (anaemias)

A

Lack of dietary iron - results in formation of microcytes (small erythrocytes).
Treat - increase iron dietary intake

63
Q

What is pernicious anaemia?

A

Autoimmune disease which attacks stomach mucosa cells. These cells usually produce intrinsic factor which is required for Vit B12 absorption. Therefore - without intrisinc factor - decreased vitamin B12 absorbed - erythrocytes grow but do not divide (produce large macrocytes)

64
Q

How could stomach surgery cause anaemia?

A

Removal of stomach mucosal cells - no intrinsic factor released - decreased reabsorption

65
Q

What types of anaemia can be caused by abnormal Hb?

A

Thalassemias

Sickle cell anaemia

66
Q

What is thalassemias?

A

Global chain abnormality (one single amino acid out of place)
Cells are very fragile - Hb deficient

67
Q

What is sickle cell anaemia?

A

Haemoglobin S.
Once Hb delivers oxygen, Hb changes shape and becomes pointy (crescent shaped). These cells are fragile and randomly rupture and block capillaries.

68
Q

What is haemostasis?

A

Process of preventing blood loss. Occurs in three stages:

  • Vascular spasm
  • Platelet plug formation
  • Coagulation
69
Q

Blood clotting is usually prevented by __________.

A

Nitric oxide and prostacyclin

70
Q

Discuss the vitamin K clotting disorder.

A

Vitamin K used by liver to produce several pro-coagulations (clotting factors)

Deficiency of Vitamin K - bleeding disorders

71
Q

Discuss the haemophilia clotting disorder.

A

Genetically inherited bleeding disorder

72
Q

Discuss the effect of aspirin on blood clotting.

A

Used to prevent unwanted clotting. This inhibits / reduces thromboxane release from platelets - less fibrinogen converted to fibrin - less clotting

73
Q

What does warfarin do?

A

Prevents unwanted clotting

74
Q

What is another name for an antibody? Where are these found?

A

Antibody = agglutinins

Distributed in plasma

75
Q

What is another name for an antigen? Where are these found?

A

Antigen = agglutinogens

Located on surface of RBCs

76
Q

What occurs during a transfusion reaction? What symptoms does this have? How is it treated?

A

Antigen / antibody reaction causes haemolysis and agglutination of RBCs in recipient

Diminishes oxygen carrying capacity (as clumps cells also impeded blood flow)
Ruptured RBCs release haemoglobin into bloodstream - which is nephrotoxic (can cause kidney renal failure).

Treatment: large volume of fluid introduced, to dilute the Hb.

77
Q

What is the difference between blood typing and cross matching?

A

Blood typing determines blood types

Cross matching is mixing of donor and recipient blood for compatibility

78
Q

What is the universal donor? What is the universal acceptor?

A
Donor = O (no antigens on cell surface)
Recipient = AB (no antibodies in plasma)