week 2 intro to blood

Question 1

how many litres of blood in a typical male

Answer 1

5 litres

• 1L in lungs
• 3L in systemic venous circulation
• 1L in heart and arterial circulation

Question 2

what are the 6 functions of blood

Answer 2

1. carriage of physiologically active compounds (plasma e.g. hormones, enzymes, waste)
2. clotting (platelets)
3. defence (white blood cells)
4. carriage of gas (red blood cells)
5. thermoregulation
6. maintenance of ECF pH

Question 3

what are the three categories of plasma proteins

Answer 3

1. albumin
2. globulin (subdivided into alpha, beta and gamma)
3. fibrinogen and other clotting factors

Question 4

what is colloid oncotic pressure

Answer 4

favours movement into capillary

Question 5

what is hydrostatic pressure

Answer 5

• favours movement out of capillary

Question 6

what is net direction of movement in ISF and blood vessels determined by

Answer 6

determined by balance between colloid oncotic pressure and hydrostatic pressure

Question 7

what is the result of colloid oncotic pressure

Answer 7

water moves in capillary

- ph not altered

Question 8

what is the common characteristic of hypoproteinaemia

Answer 8

oedema due to loss of oncotic pressure

Question 9

what are the causes of hypoproteinaemai

Answer 9

• prolonged starvation
• liver disease
• intestinal diseases
• nephrosis (kidney disease)

Question 10

what is the lifespan of erythrocytes

Answer 10

120 days

Question 11

what does erythropoietin do

Answer 11

controls and accelerates erythropoiesis (formation of red blood cells)

Question 12

where is erythropoietin secreted

Answer 12

85% - kidney

15% - liver

Question 13

how does erythropoietin work

Answer 13

• as pluripotent stem cells are becoming erythroblasts, erythropoietin stimulates this reaction

Question 14

when is secretion of erythropoietin enhanced

Answer 14

when oxygen delivery to kidneys is reduced (hypoxia)
this could be caused by: haemorrhage, anaemia, cardiac dysfunction, lung disease
- there is a 2-3 day delay in enhancement of erythropoiesis

Question 15

what are the main types of white blood cells

Answer 15

granulocytes 
- neutrophils 
- eosinophils 
- basophils
 agranulocytes 
- monocytes 
- lymphocytes (B cells and T cells - helper T cells or killer T cells)

Question 16

difference between monocytes and macrophages

Answer 16

after 72 hours monocytes migrate to connective tissue where they become macrophages and live for 3 months

• so monocytes in blood
• macrophages in connective tissue

Question 17

what is leukopoiesis

Answer 17

white blood cell formation

Question 18

what is leukopoiesis controlled by

Answer 18

controlled by cocktail of cytokines (proteins/peptides released from one cell type which act on another)

• colony stimulating factors e.g. granulocyte colony stimulating factors
• interleukins (inter=between, leukins=white blood cell)

Question 19

what does bacterial infection cause

Answer 19

increase in neutrophils

Question 20

what does viral infection cause

Answer 20

increase in lymphocytes

Question 21

what are platelets

Answer 21

membrane bound cell fragments from megakaryocytic (rarely nucleated)

Question 22

what is the lifespan of platelets

Answer 22

10 days

Question 23

what is the formation of platelets governed by

Answer 23

thrombopoietin

Question 24

what is a haematocrit

Answer 24

measurement of the percentage of red blood cells to the whole blood

Question 25

what is the normal range in haematocrit

Answer 25

40-50%

Question 26

what is bilirubin

Answer 26

the breakdown product of red blood cells

Question 27

what factors can change viscosity

Answer 27

• increase in haematocrit means increased viscosity
• decrease in temperature increases viscosity
• decreased flow rate increases viscosity