Introduction to Blood

Question 1

Describe some functions of blood

Answer 1

• Carriage of physiologically active compounds
• Thermoregulation
• Maintenance of ECF pH

Question 2

Approx. how much blood is there in a healthy 70kg man?

Answer 2

5 litres

Question 3

Describe the approximate distribution of blood in the body

Answer 3

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

Question 4

What percentage of body weight is blood in the average woman?

Answer 4

7-8%

Question 5

How much blood is in an average neonate?

Answer 5

350mo (about a coke can)

Question 6

Describe the composition of blood

Answer 6

Plasma, red and white blood cells, platelets

Question 7

Describe the composition of plasma

Answer 7

95% water - circulates biological active compounds; contains plasma proteins

Question 8

What categories of plasma proteins are there?

Answer 8

Albumin, globulins and fibrinogen (and other clotting factors)

Question 9

What three types of globulins are there?

Answer 9

alpha, beta and gamma

Question 10

What is colloid oncotic pressure?

Answer 10

A type of osmotic pressure exerted by plasma proteins tending to draw fluid into the circulatory system

Question 11

Movement of fluid between capillary and interstitial space is subject to what two forces?

Answer 11

Hydrostatic pressure and colloid oncotic pressure

Question 12

As colloid pressure is relatively constant, movement of fluid therefore depends on a balance between what?

Answer 12

Capillary hydrostatic pressure (CHP) and interstitial hydrostatic pressure (IHP)

Question 13

What is hypoproteinaemia?

Answer 13

Abnormally low levels of circulating plasma protein

Question 14

What are the causes of hypoproteinaemia?

Answer 14

Prolonged starvation, liver disease, intestinal diseases, nephrosis (kidney disease)

Question 15

What is a common characteristic of hypoproteinaemia?

Answer 15

Oedema due to loss of oncotic pressure

Question 16

What is the lifespan of an erythrocyte?

Answer 16

120 days

Question 17

Describe the action of erythropoiesis

Answer 17

Pluripotent stem cells differentiate into erythroblasts in presence of erythropoietin - erythroblasts mature into erythrocytes

Question 18

How do neutrophils entrap microorganisms?

Answer 18

NETS (Neutrophil extracellular traps)

Question 19

Describe the process of leukopoiesis

Answer 19

Cytokines released from endothelial cells, fibroblasts and white blood cells stimulate mitosis and maturation of leukocytes

Question 20

How does the proportion of neutrophils to lymphocytes change depending on the infection type?

Answer 20

Bacterial - more neutrophils

Viral - more lymphocytes

Question 21

What are platelets?

Answer 21

Membrane bound cell fragments of megakaryocytes

Question 22

What hormone governs the production of platelets?

Answer 22

Thrombopoietin

Question 23

What is a haematocrit?

Answer 23

Centrifuged sample of whole blood tissue which displays separate constituent parts of tissue