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Flashcards in Microbiology Deck (40):
1

What is the name of this cell and how prevalent is it in blood? (2)

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Basophil (about 1%)

2

What is the name of these cells and how prevalent are they in blood?

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Eosinophils (around 3%)

3

What is the name of this cell and how prevalent is it in blood?

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Lymphocyte (around 28%)

4

What is the name of this cell and how prevalent is it in blood?

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Monocytes (around 8%)

5

What is the name of this cell and how prevalent is it in blood?

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Neutrophils (around 60%)

6

What would cause an increase in the percentage of neutrophils?

  • Stress
    • physiological or pathological
    • acute infection
    • trauma
    • infarction
    • inflammation
  • Steroids can cause demargination

7

What would cause an increase in the percentage of eosinophils?

  • Parasitic infections
  • hypersensitivity/ allergic reactions

8

What would cause an increase in the percentage of basophils?

  • hypersensitivity reactions

9

What do red cells have instead of a nucleus?

Hb

10

What does a lack of iron or B12 do to red cells? (MCV)

It can alter their size

11

What does lower Hb suggest?

Anaemia 

an=without

aemia=blood

12

What type of anaemia does a patient have if it presents on a microcytic level?

iron deficiency!

e.g. chronic blood loss

13

What type of anaemia does a patient have if it presents on a macrocytic level?

Vitamic B12/ folate deficiency

(nuclear defects)

14

What type of anaemia does a patient have if it presents on a normocytic level?

  • Acute blood loss
  • Anaemia of chronic disease (eg inflammation, infection)

15

What other changes may chronic disease anaemia cause in blood results?

Changes in

  • iron homeostasis
  • the proliferation of erythroid cells
  • the production of erythropoeirin
  • the life span of red cells

16

What would you worry about if a patient has a high Hb level?

  • False result- dehydration
  • Secondary cause- hypoxia driven
  • Primary- bone marrow disorder

17

What additional abnormalities can blood films indentify (that analysers cannot)?

  • target cells in liver disease
  • red cell fragmentation
    • reflecting mechanical damage

18

What would cause an increase in the percentage of monocytes?

  • chronic infections
  • malignancy
  • autoimmune disorders

19

What would cause an increase in the percentage of Lymphocytes?

  • Viral infections
    • eg glandular fever, 'reactive' or activated lymphocytes

20

What aspects of plasma are you interested in?

  • Coagulation proteins
  • Plasma viscosity

21

What is haemostasis?

The arrest of bleeding and the maintenance of vascular patency

22

What are the four requirements of haemostasis?

  • Permanent state of readiness
  • Prompt response
  • Localised response
  • Protection against unwanted thrombosis

23

What are the four components of a regular haemostatic system?

  • Formation of platelet plug
    • primary haemostasis
  • Formation of fibrin clot
    • secondary haemostasis
  • Fibrinolysis
  • Anticoagulant defences

24

What kind of cells are platelets?

Small anucleate discs

25

What is the mean lifespan of platelets?

7-10 days

26

What to platelets adhere to and where?

They adhere to the collagen at the site of endothelial injury

27

What happens after platelets adhere to the injury site?

  • There is secretion of various chemicals from the platelets
  • There is then aggregation of platelets at the site of injury

28

Where do reactions of secondary haemostasis occur?

The surface of platelets

29

What causes a false low platelet count?

The formation of clumps in the collection tube, confusing the analyser 

30

What causes a genuine low platelet count?

  • inbalance in production
    • drugs
  • consumption/trapping
    • acute blood loss
    • enlarged spleen

31

Does high platelet count affect haemostasis?

No

32

What are the causes of a high platelet count?

  • blood loss
  • iron deficiency
  • inflammation 
  • malignancies

33

What is the process of secondary haemostasis?

Fibrin clot formation

  • series of reactions involving activation of coagulation factors to an active state (pro-enzyme to enzyme), that results in the conversion of  soluble fibrinogen to insoluble fibrin

34

What does a coagulation screen measure?

  • time taken to form a fibrin clot along diffferent coagulation pathways
  • coagulation activities in vitro

35

What coagulation screens do you know?

  • prothrombrin time, PT (II, V, VII, X)
  • activated partial thrombroplastin time, aPTT (II, V, VIII, IX, X, XI, XII)

36

What are D-dimers?

Degranulation products of fibrin (from fibrinogen) can reflect increased fibrin deposition

  • post surgery
  • heart failure
  • malignancy
  • abnormal thrombus

37

What causes changes in coagulation times?

Prolongation due to multiple coagulation factor deficiencies

  • liver disease (production problem)
  • disseminated intravascular coagulation (DIC, consumption problem)

 

38

What does plasma viscosity indicate?

It is an index of changes in plasma proteins (fibrinogen and some globulins)

39

What do changes in plasma viscosity relect?

Can reflect

  1. systemic inflammtion
  2. less commonly- haematological malignancies producing an abnormal protein

40