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Science for Medicine > Blood > Flashcards

Flashcards in Blood Deck (40):
1

What is the average circulating volume of blood in the typical adult male?

5 litres

2

What is the distribution of blood in the typical adult male?

- 1 litre in lungs
- 3 litres in systemic venous circulation
- 1 litre in the heart and arterial circulation

3

What are the functions of blood?

- carriage of physiologically active compounds
- clotting
- defence
- carriage of gas
- thermoregulation
- maintenance of ECF pH

4

What physiologically active compounds are carried in the blood?

- hormones
- enzymes
- nutrients

5

What constituents of the blood facilitate clotting?

- prothrombin
- fibrinogen

6

What constituent of the blood is involved in defence?

Leukocytes

7

Explain the basic mechanisms of thermoregulation

- vasodilation when hot
- vasoconstriction when cold

8

What percentage of plasma is water?

95%

9

What is the function of plasma?

Used to circulate biologically active molecules and compounds

10

What can small changes in protein composition be indicative of?

Problems elsewhere

11

What three subcategories can plasma proteins be divided into?

- albumin
- globulins
- fibrinogen and other clotting factors

12

What is the function of albumin in the plasma?

- transports lipid and steroid hormones
- helps create colloid oncotic pressure

13

What is the function of globulins in the plasma?

- alpha/beta transport of lipids and fat-soluble vitamins
- gamma globulins are antibodies

14

What is oncotic pressure?

Pressure that can pull water from the interstitial space into the lumen

15

Plasma proteins do not readily cross the capillary wall, they ___

displace water and create and osmotic potential

16

What happens when water is moved from interstitial space into the lumen?

Chemicals and nutrients also move, however this only changes the volume, not the concentration

17

What is the function of RBCs?

Carry oxygen around the body using haemoglobin

18

Describe RBCs

- most abundant
- 120 day life span
- highly flexible
- bi-concave
- non-nucleated

19

What controls and accelerates Erythropoiesis?

Erythropoietin

20

Where is Erythropoietin mainly secreted?

By the peritubular capillary cells (85%) found in the kidneys and hepatocytes of the liver (15%)

21

What is the function of Erythropoietin?

Speeds up differentiation of pluripotent stem cells into erythroblasts

22

Secretion of Erythropoietin is increased when

oxygen supply to the kidneys is reduced

23

Give four factors which might cause reduced oxygen supply to the kidneys

- hypoxia
- haemorrhage
- anaemia
- lung disease

24

Name the five main types of white blood cells

- neutrophils
- eosinophils
- basophils
- monocytes
- lymphocytes

25

What percentage of WBC population are neutrophils?

68%

26

Give the functions of neutrophils

- half life of around 6 hours
- phagocytic and mainly deal with bacterial infection
- can trap bacteria in NETS

27

Give the functions of eosinophils

- attack pathogens too large for other leukocytes e.g. parasites
- number rapidly increases in allergic reactions

28

Give the functions of basophils

- release histamine and heparin
- promote inflammation

29

Give the functions of monocytes

- largest leukocyte
- 72 hour life span in circulation
- migrate to tissues and become macrophages (phagocytic)

30

Give the functions of lymphocytes

- key components of immune system
- T and B cell variants

31

What controls Leukopoiesis?

- growth stimulating factors
- interleukins

32

Where are growth stimulating factors and interleukins released?

By endothelial cells, fibroblasts and mature white cells

33

What do growth stimulating factors and interleukins stimulate?

Mitosis and maturation of leukocytes

34

Leukopoiesis is controlled by a cocktail of cytokines which is dynamic and

changes its composition to suit which specific cell type is needed and any given moment

35

Describe platelets

- unique membrane bound fragments of megakaryocytes
- formation governed by thrombopoietin

36

Give the functions of platelets

- adhere to damaged capillary walls and expose connective tissue to mediate blood clotting
- do not adhere to healthy epithelium

37

What is haematocrit?

The percentage of blood made up of red blood cells

38

What is the usual percentage of haematocrit in males and females respectively?

males - 40-54%
females - 37-47%

39

What might increase haematocrit?

Living at altitude due to the need for more haemoglobin to bind lower conc. of oxygen

40

What is blood viscosity?

The thickness of blood in comparison to water
- plasma is 1.8x thicker
- whole blood is 3-4x thicker
- can change with haematocrit, temperature and flow rate