Physiology Flashcards

1
Q

What is blood?

A

Specialised fluid composed of cells suspended in a liquid called plasma

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2
Q

What is the average adult blood volume in litres?

A

4.5-6 litres

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3
Q

What are the 3 types of blood cell?

A

Red blood cell
White blood cell
Platelets

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4
Q

What are the main components of plasma?

A

Water (90%)
Proteins (mostly albumin, Ig, clotting factors)
Nutrients
Salts

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5
Q

What are the 2 types of white cells?

A

Granulocytes

Agranulocytes

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6
Q

List the main granulocytes

A

Neutrophils
Eosinophils
Basophils

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7
Q

List the main agranulocytes

A

Lymphocytes

Monocytes

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8
Q

What do red blood cells do?

A

Carry oxygen

Buffer CO2

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9
Q

What do platelets do?

A

Stop bleeding

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10
Q

What do white blood cells do?

A

Fight infection and pathology

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11
Q

What is the process by which blood cells are produced?

A

Haemopoiesis from pleuripotent stem cells

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12
Q

Where are the sites of haematopoiesis in the embryo?

A

Yolk sac
Liver
Spleen

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13
Q

Where are the sites of haematopoiesis from birth to maturity?

A

Bone marrow
Liver
Spleen

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14
Q

Where are the sites of haematopoiesis in the adult?

A

Bone marrow of skull, ribs, sternum, pelvis and proximal femur

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15
Q

What processes have to occur to a stem cell in order to make blood?

A

Proliferation
Differentiation
Self-renewal
Quiescence

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16
Q

Outline the cell stages of erythropoiesis

A

Pronormoblast - early normoblast - intermediate normoblast - late normoblast - reticulocyte - erythrocyte

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17
Q

Describe the structure of a neutrophil

A
Segmented nucleus (polymorph)
Neutral-staining
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18
Q

What are the functions of a neutrophil?

A

Phagocytose invaders

Attract other immune cells

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19
Q

Describe the structure of a eosinophil

A

Bi-lobed

Bright orange-red granules

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20
Q

What are the functions of an eosinophil?

A

Fight parasitic infections

Involved in hypersensitivity

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21
Q

Describe the structure of a basophil

A

Infrequent in circulation

Large deep purple granules with obscured nucleus

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22
Q

What are the functions of a basophil?

A

Circulating version of a mast cell

Mediates hypersensitivity

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23
Q

Describe the structure of a monocyte

A

Large single nucleus

Faintly staining granules, often vacuolated

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24
Q

What are the functions of a monocyte?

A

Enter tissues and become macrophages
Phagocytose invaders
Attract other immune cells
Live longer than neutrophils

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25
Q

Describe the structure of a lymphocyte

A

Mature: small with condensed nucleus and cytoplasm
Activated: blue cytoplasm extending neighbouring red cells with more open nucleus

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26
Q

What are the functions of a lymphocyte?

A

Numerous subtypes and functions

Cognate response

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27
Q

What methods can be used to identify primitive precursors?

A

Immunophenotype (antigen on cell surface)

Bio-assay (culture in vitro)

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28
Q

What is a common site for bone marrow biopsy?

A

Posterior iliac crest

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29
Q

Do red blood cells have a nucleus and/or mitochondria?

A

No nucleus or mitochondria, thus no DNA either

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30
Q

What is the average life-span of a red blood cell?

A

120 days

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31
Q

Red blood cells are produced from pleuripotent stem cells. True/False?

A

True

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32
Q

What happens to old red blood cells?

A

Phagocytic cells of the liver and spleen engulf old red blood cells

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33
Q

What happens to the haem group of broken down red blood cells?

A

Converted into bilirubin that is conjugated by the liver

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34
Q

Which hormone regulates erythrocyte production?

A

Erythropoietin

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35
Q

What stimulates erythropoietin release by the kidney?

A

Reduced oxygen carrying capacity of erythrocytes

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36
Q

At which stage of erythropoiesis does no further cell division take place? (i.e. not pleuripotent cells)

A

When polychromatic erythroblast forms (Hb in cytoplasm)

37
Q

How do red blood cells synthesise ATP/energy? N.B. remember no mitochondria

A

Anaerobic glycolysis

38
Q

Which compound is produced when there is reduced phosphate in the blood? What effect does this compound exert?

A

2,3-BPG

This releases O2 from Hb

39
Q

Glutathione is a tripeptide consisting of which amino acids?

A

Glutamate
Cysteine
Glycine

40
Q

What does glutathione protect against?

A

Toxic effects of oxygen free radicals

41
Q

In what 3 forms is CO2 transferred to the lungs?

A
Physically dissolved (10%)
Bound to Hb (30%)
As bicarbonate (60%)
42
Q

Which enzyme is vital for CO2 transport?

A

Carbonic anhydrase

43
Q

How does the composition of adult and foetal Hb differ?

A

Foetal: alpha2-gamma2
Adult: alpha2-beta2

44
Q

Foetal Hb has a higher affinity for O2 than adult Hb. True/False?

A

True

45
Q

Foetal Hb has a higher affinity for 2,3-BPG than adult Hb. True/False?

A

False

Foetal Hb has less affinity for 2,3-BPG than adult Hb, favouring O2 transfer from mother to foetus during pregnancy

46
Q

What is haemopoiesis?

A

Formation of blood cells

47
Q

What are mature red blood cells called?

A

Erythrocytes

48
Q

List the main groups of mature white blood cells

A

Granulocytes (neutrophils, basophils, eosinophils)
Monocytes (macrophages)
Lymphocytes (B cells, T cells, NK cells)

49
Q

State the lifespan for a red blood cell, neutrophil and platelet

A

Red cell: 120 days
Neutrophil: 7-8 hours
Platelet: 7-10 days

50
Q

Why is a reticulocyte blue on blood film?

A

Doesn’t have the full amount of Hb yet

51
Q

Outline the progression from precursor to mature neutrophil

A

Myeloblast - promyelocyte - myelocyte - metamyelocyte - neutrophil

52
Q

Where do precursor cells of blood cells come from? (what is the precursor of the precursors?!)

A

Haemopoietic progenitor cell, derived from stem cells

53
Q

Self-renewal is a property of all haemopoietic cells. True/False?

A

False

Only occurs in stem cells; lost in descendants

54
Q

Which germ cell layer are haemopoietic stem cells derived from?

A

Mesoderm

55
Q

Circulating haemopoietic progenitors are detectable as early as week _ of life

A

Circulating haemopoietic progenitors are detectable as early as week 5 of life

56
Q

What is the first site of erythroid activity? When does this activity stop?

A

Yolk sac

Stops by week 10

57
Q

When does the liver begin erythroid activity?

A

Week 6

58
Q

When does the spleen begin erythroid activity?

A

Week 12

59
Q

When does the bone marrow begin erythroid activity?

A

Week 16

60
Q

List the main bony sites of haemopoiesis post-natally

A

Tibia and femur
Vertebra
Sternum
Ribs

61
Q

Osteoblasts form/resorb bone and osteoclasts form/resorb bone

A

Osteoblasts form bone and osteoclasts resorb bone

62
Q

What part of long bones - epiphysis, metaphysis or diaphysis - involves the most haemopoiesis?

A

Metaphysis

63
Q

What is “red” and “yellow” marrow?

A

Red marrow: haemopoietically active
Yellow marrow: fatty and inactive
With age, yellow marrow replaces red marrow

64
Q

What regulates neutrophil maturation?

A

Granulocyte-colony stimulating factor (G-CSF)

65
Q

How is haemopoiesis assessed?

A

Blood count
Cell indices
Morphology (blood film)
Bone marrow examination

66
Q

What specialist tests can be done to analyse haemopoietic precursor cells?

A

Immunophenotyping
Cytochemistry
Clonogenic assay
Animal modelling

67
Q

Where are haemopoietic stem cells of lymphoid cells located?

A

Liver in foetus

Bone marrow post-natally

68
Q

Where are precursor lymphoid cells located?

A
Bone marrow (B-cells)
Thymus (T-cells)
69
Q

List the main peripheral (secondary) lymphoid tissues

A

Spleen
Lymph nodes
Tonsils

70
Q

What are the functions of the lymphatic system?

A

Return lymph (tissue fluid) to circulation in homeostasis
Prevent accumulation of fluid in tissues (oedema)
Filter lymph of toxins

71
Q

What is haemostasis?

A

Cessation of bleeding whilst maintaining vascular patency

72
Q

List the main components/processes of normal haemostasis

A

Formation of platelet plug (primary haemostasis)
Formation of fibrin clot (secondary haemostasis)
Fibrinolysis
Anticoagulation

73
Q

What is the lifespan of a platelet?

A

7-10 days

74
Q

Following endothelial vessel wall damage, collagen is exposed and releases which factor to attract platelets to adhere?

A

Von Willebrand Factor

75
Q

Why is platelet plug formation impaired in older people, causing easy bruising?

A

Lose collagen from vessel wall with age - less Von Willebrand Factor and thus less platelet adherance and aggregation

76
Q

List some consequences of failure of platelet plug formation

A

Spontaneous bleeding
Purpura
Mucosal bleed (epistaxis, GI, conjunctival)
Haemorrhage

77
Q

What is the main screening test/investigation for primary haemostasis?

A

Platelet count

78
Q

Which factor is released from damaged vascular endothelium during fibrin clot formation? Which factor does it activate?

A

Tissue factor

activates factor VIIa

79
Q

Which factors are activated by factor VIIa, VIII and IXa in fibrin clot formation?

A

V

Xa

80
Q

What is the effect of factors V and Xa in the propagation step of fibrin clot formation?

A

Encourage formation of thrombin from prothrombin

81
Q

What is the effect of thrombin in fibrin clot formation?

A

Encourages formation of fibrin from fibrinogen

82
Q

Single clotting factor deficiency is usually hereditary - give an example of a condition

A

Hereditary haemophilia

83
Q

Multiple clotting factor deficiency is usually acquired - give an example of a condition

A

Disseminated intravascular coagulation

84
Q

Describe the fibrinolytic pathway (breakdown of a clot)

A

Tissue plasminogen factor causes plasmin formation from plasminogen
Plasmin causes breakdown of fibrin to fibrin degradation products (D-dimers)

85
Q

What are the main screening tests/investigations for secondary haemostasis?

A
Prothrombin time (PT time)
Activated partial thromboplastin time (APTT)
86
Q

If the PT time is prolonged and the APT time is normal, which factors are causing the problem?

A

Tissue factor

VIIa

87
Q

If the PT time is normal and the APT time is prolonged, which factors are causing the problem?

A

VIII

IXa

88
Q

Warfarin affects the PT time and heparin affects the APT time. True/False?

A

True