Blood

Question 1

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

Answer 1

5 litres

Question 2

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

Answer 2

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

Question 3

What are the functions of blood?

Answer 3

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

Question 4

What physiologically active compounds are carried in the blood?

Answer 4

• hormones
• enzymes
• nutrients

Question 5

What constituents of the blood facilitate clotting?

Answer 5

• prothrombin

- fibrinogen

Question 6

What constituent of the blood is involved in defence?

Answer 6

Leukocytes

Question 7

Explain the basic mechanisms of thermoregulation

Answer 7

• vasodilation when hot

- vasoconstriction when cold

Question 8

What percentage of plasma is water?

Answer 8

95%

Question 9

What is the function of plasma?

Answer 9

Used to circulate biologically active molecules and compounds

Question 10

What can small changes in protein composition be indicative of?

Answer 10

Problems elsewhere

Question 11

What three subcategories can plasma proteins be divided into?

Answer 11

• albumin
• globulins
• fibrinogen and other clotting factors

Question 12

What is the function of albumin in the plasma?

Answer 12

• transports lipid and steroid hormones

- helps create colloid oncotic pressure

Question 13

What is the function of globulins in the plasma?

Answer 13

• alpha/beta transport of lipids and fat-soluble vitamins

- gamma globulins are antibodies

Question 14

What is oncotic pressure?

Answer 14

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

Question 15

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

Answer 15

displace water and create and osmotic potential

Question 16

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

Answer 16

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

Question 17

What is the function of RBCs?

Answer 17

Carry oxygen around the body using haemoglobin

Question 18

Describe RBCs

Answer 18

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

Question 19

What controls and accelerates Erythropoiesis?

Answer 19

Erythropoietin

Question 20

Where is Erythropoietin mainly secreted?

Answer 20

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

Question 21

What is the function of Erythropoietin?

Answer 21

Speeds up differentiation of pluripotent stem cells into erythroblasts

Question 22

Secretion of Erythropoietin is increased when

Answer 22

oxygen supply to the kidneys is reduced

Question 23

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

Answer 23

• hypoxia
• haemorrhage
• anaemia
• lung disease

Question 24

Name the five main types of white blood cells

Answer 24

• neutrophils
• eosinophils
• basophils
• monocytes
• lymphocytes

Question 25

What percentage of WBC population are neutrophils?

Answer 25

68%

Question 26

Give the functions of neutrophils

Answer 26

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

Question 27

Give the functions of eosinophils

Answer 27

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

Question 28

Give the functions of basophils

Answer 28

• release histamine and heparin

- promote inflammation

Question 29

Give the functions of monocytes

Answer 29

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

Question 30

Give the functions of lymphocytes

Answer 30

• key components of immune system

- T and B cell variants

Question 31

What controls Leukopoiesis?

Answer 31

• growth stimulating factors

- interleukins

Question 32

Where are growth stimulating factors and interleukins released?

Answer 32

By endothelial cells, fibroblasts and mature white cells

Question 33

What do growth stimulating factors and interleukins stimulate?

Answer 33

Mitosis and maturation of leukocytes

Question 34

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

Answer 34

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

Question 35

Describe platelets

Answer 35

• unique membrane bound fragments of megakaryocytes

- formation governed by thrombopoietin

Question 36

Give the functions of platelets

Answer 36

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

Question 37

What is haematocrit?

Answer 37

The percentage of blood made up of red blood cells

Question 38

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

Answer 38

males - 40-54%

females - 37-47%

Question 39

What might increase haematocrit?

Answer 39

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

Question 40

What is blood viscosity?

Answer 40

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