ToB 20 Blood Cells and Haematopoiesis Flashcards

1
Q

What is the life span of a Red blood cell?

A

~ 120 days

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2
Q

What is the lifespan of a platelet?

A

~ 10 days

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3
Q

What is the lifespan of a neutrophil?

A

~ 2-4 days

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4
Q

What is the lifespan of a lymphocyte?

A

Between 1 day - years

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5
Q

Where are RBC’s, platelets and most WBC’s produced?

A

Bone marrow

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6
Q

What organ removes blood cells from the circulation?

A

Spleen

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7
Q

Name the 5 main (flat) bones which contain red bone marrow:

A
1- Pelvis
2- Sternum
3- Ribs
4- Vertebrae
5- Skull
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8
Q

Red bone marrow has approximately what percentage of fat?

A

50%

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9
Q

What is the name of the cell from which all blood cells are derived?

A

Multipotential haematopoetic stem cell

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10
Q

What are the 4 types of granular cells?

A

1- Eosinophil
2- Neutrophil
3- Monocyte
4- Basophil

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11
Q

What is the difference between a monocyte and a macrophage?

A

Monocytes are the precursor of macrophages, and are present in the blood stream, while macrophages are present in the ECF

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12
Q

What are the 5 main functions of RBC’s?

A
1- Carry oxygen to tissues
2- Maintain Hb in its reduced state
3- Carry Hb
4- Maintain osmotic equilibrium
5- Generate ATP
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13
Q

Why can’t RBC’s create protein?

A

No nucleus = no DNA = no mRNA = no protein

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14
Q

Why is it important that RBC’s are biconcave?

A

1- Maximise SA:vol ratio, for quicker diffusion of O2 and CO2
2- Increase flexibility for passage through microcirculation

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15
Q

What is the diameter of a RBC?

A

8 um

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16
Q

What are the 2 configurations of a RBC?

A
Oxyhaemoglobin = R state (relaxed)
Deoxyhaemoglobin = T state (tight)
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17
Q

How would a decrease in pH affect the configuration of a RBC?

A

Promote T state = Deoxyhaemoglobin (Bohr shift)

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18
Q

How would a decrease in temperature affect the configuration of a RBC?

A

Promote R state = Oxyhaemoglobin

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19
Q

Describe the shape of the oxygen-dissociation curve:

A

Sigmoidal

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20
Q

What happens to the oxygen dissociation curve during the Bohr effect?

A

Curve shifts to the right

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21
Q

What is the Bohr effect?

A

When specific environmental changes: Decrease in pH, increase in CO2 and temp, affect the oxygen-binding affinity of RBC’s, and promote the formation of deoxyhaemoglobin

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22
Q

Which globin genes predominate in an adult?

A

alpha and beta globins

23
Q

Which globin genes predominate in a foetus?

A

alpha and gamma globins

24
Q

When does the switch from gamma globin to beta globin occur?

A

~ 3-6 months after birth

25
Q

Name the 2 main metabolic pathways in RBC’s:

A

1- Embden Meyerhof pathway

2- Pentose Phosphate pathway

26
Q

Which metabolic pathway allows RBC’s to generate ATP?

A

Embden Meyerhof pathway

27
Q

The Embden Meyerhof pathway metabolises Glucose to what?

A

Lactate

28
Q

Which metabolic pathway allows RBC’s to generate NADPH?

A

Pentose Phosphate Pathway

29
Q

The Pentose Phosphate Pathway metabolises Glucose 6-phosphate to what?

A

Fructose 6-phosphate and

Glyceraldehyde 3-phosphate

30
Q

What is the main function of the pentose phosphate pathway in RBC’s?

A

Generate NADPH

to protect against oxidative damage (via Glutathione)

31
Q

Cells in which organ detect a fall in pO2, resulting in Erythropoetin release?

A

Kidney (interstitial peritubular cells)

32
Q

What is Erythropoetin?

A

Hormone produced and released from the Kidneys, which stimulates RBC maturation and release in bone marrow

33
Q

Which hormone controls Erythropoesis, and where is it produced and released from?

A

Erythropoetin, from the Kidneys

34
Q

Describe the negative feedback loop of Erythropoetin:

A
  • Kidneys detect fall in pO2
  • Kidneys increase production and release of Erthyropoetin
  • Erythropoetin increases RBC maturation and release
  • Kidneys detect rise in pO2
  • Kidneys decrease production of Erthyropoetin
35
Q

How is an old/damaged RBC broken down and excreted?

A
  • Removed from circulation by spleen,
  • Macrophage within Spleen breaks Haem into uncongugated bilirubin
  • This converted to conjugated bilirubin in the liver
  • Passes through bile duct into s. intestine
  • Colonic bacteria deconjugate and convert to urobilinogen
  • Absorbed and excreted by kidneys in urine
36
Q

Define platelets:

A

Tiny fractions of blood cells produced by Megakaryocytes

37
Q

Which hormone controls platelet production?

A

Thrombopoetin

38
Q

In which organ are majority of platelets stored?

A

Spleen

39
Q

What is the main function of platelets?

A

Formation of blood clot

40
Q

How do platelets promote blood clot formation?

A
  • Adhesion to connective tissue
  • Aggregate together = platelet plug
  • Specific phospholipid membrane receptors to activate clotting cascade
41
Q

What 2 bodies are found within platelets?

A

1- Dense bodies

2- alpha granules

42
Q

What do the alpha granules of platelets contain?

A

Glycoproteins

43
Q

What do the dense bodies of platelets contain?

A

Serotonin, ADP, Catecholamines and Calcium

44
Q

Neutrophil maturation is controlled (mostly) by which growth factor?

A

G-CSF

45
Q

Which growth factor enhances the chemotaxis and phagocytosis time of neutrophils?

A

G-CSF

46
Q

Neutrophils contain granules. What is the function of these granules?

A

Contain enzymes (Defensins, Lyzozymes, Lactoferrin etc) for use when phagocytosing pathogens

47
Q

Name the 4 main phagocytic cell types contained within the Reticuloendothelial system:

A

1- Monocytes (circulation)
2- Macrophages (tissue)
3- Kupffer cells (liver)
4- Microglial cells (CNS)

48
Q

What are the main organs in the Reticuloendothelial system?

A

Spleen, Liver and Lymph Nodes

49
Q

Lymph Nodes are mostly found in which 3 locations?

A
  • Armpit
  • Neck
  • Groin
50
Q

Which granular cell mainly mediate allergic reactions?

A

Eosinophil

51
Q

Where are T lymphocytes created?

A

Bone marrow

52
Q

Where do T lymphocytes mature?

A

Thymus

53
Q

T lymphocytes can mature into which 3 cell types?

A
  • T helper cell
  • NK cells
  • T cytotoxic cells