Introduction to Blood

Question 1

State the average circulating volume in a typical adult male

Answer 1

5L

Question 2

State the average circulating volume in a typical newborn baby

Answer 2

350ml

Question 3

Desribe the ditribution of blood

Answer 3

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

Question 4

List the functions of blood

Answer 4

Carriage of physiologically active compounds e.g hormones, enzymes, nutrients
Thermoregulation – vasodilate when cold and vasoconstrict
Carriage of gas – CO2 and O2
Maintenance of ECF pH (7.4)
Defence – white blood cells
Clotting – platelets

Question 5

Describe the composition of plasma

Answer 5

95% water
5% plasma proteins

Question 6

Name the plasma proteins

Answer 6

Albumin
Globulin
Fibrinogen and other clotting factors

Question 7

Define the term oncotic pressure and describe the factors responsible for generation

Answer 7

Plasma proteins cannot cross the capillary wall. They displace water which creates an osmotic potential. This creates a pressure that can pull water from the interstitial fluid into the lumen. When water moves it brings chemicals and nutrients too, however this only changes the volume and not the concentration.

Water and nutrients move together, so while the distribution of water volume between compartments changes the composition remains the same.

Question 8

State the normal lifespan of red blood cell in the circulation

Answer 8

120 days

Question 9

State the normal lifespan of platelets blood cell in the circulation

Answer 9

10 days

Question 10

Describe the function of the red blood cell

Answer 10

Red blood cells are responsible for gas transport around the body

Question 11

What is haemopoeisis?

Answer 11

The formation of blood cells

Question 12

What is erythropoeisis?

Answer 12

The formation of red blood cells

Question 13

Describe the function of erythropoietin, where it is synthesised and the factors which may increase secretion

Answer 13

Erythropoietin controls and accelerates the formation of red blood cells

Question 14

Where is erythropoeitin synthesed?

Answer 14

85% Kidney
15% Liver

Question 15

What stimulates release of erythropoeitin?

Answer 15

Reduced oxygen delivery to the kidneys

Question 16

What factors can reduce blood flow to kidneys?

Answer 16

Cardiac dysfunction
Haemorrage
Lung disease
Anaemia

Question 17

Name the five main types of white blood cells

Answer 17

Neutrophils
Basophils
Eosinophiols
Lymphocytes
Monocytes

Question 18

Classify the different types of blood cells

Answer 18

Eryhtrocytes and leukocytes

Myeloid and lymphoid

Question 19

State the difference between a monocyte and a macrophage

Answer 19

Monocytes are the largest type of white blood cell and become macrophages once they migrate from the blood stream into any tissue in the body.

Question 20

What is leukopoiesis?

Answer 20

The formation of white blood cells

Question 21

Describe the process of leukopoiesis

Answer 21

Leukopoiesis is controlled by cytokines
Cytokines are released by mature WBC and stimulate mitosis and maturation of leukocytes
The composition of cytokines changes in response to infection to influence which WBC will be preferentially differentiated

Question 22

Outline the role of thrombopoietin in platelet formation

Answer 22

Thrombopoietin regulates the number of platelets in the blood by stimulating an increase in the number and growth of megakaryocytes to control the rate of platelet production

Question 23

Define what is meant by haematocrit

Answer 23

Haemocrit refers to the percentage of blood made up by red blood cells

Question 24

State the normal value for the haematocrit

Answer 24

40-50%

Question 25

State how the haemocrit may change in certain circumstances

Answer 25

For example, living at high altitude can increase haemocrit due to the need of more haemoglobin to bind to the lower oxygen concentration

Question 26

Define what is meant by blood viscosity

Answer 26

Blood viscosity refers to the thickness of blood in comparison to water

Question 27

Describe the viscosity of plasma and blood in compairosn to water

Answer 27

Plasma is around 1.8x thicker Whole blood is around 3-4x thicker.

Question 28

Describe how viscosity may change in certain circumstances

Answer 28

Haemocrit – an increase in haemocrit will increase the viscosity Temperature – an increase in temperature will decrease viscosity and vice versa Flow rate – a decreased flow rate will increase viscosity and vice versa

Question 29

What colour is plasma?

Answer 29

Yellow

Question 30

Why is plasma yellow?

Answer 30

The prescence product of red blood cell breakdown called biliruben