Blood

Question 1

What are the main two components of blood? And what are their relevant compositions?

Answer 1

Plasma (55%) and Red Blood Cell (45%)

Question 2

What is the haematocrit?

Answer 2

ratio of the volume of red blood cells to the total volume of blood

Question 3

What composition of the plasma in blood is made up of water? What is the rest?

Answer 3

Water - 91%
Proteins- 7 %
Other solutes are 2%

Question 4

How do you collect blood for analysis?

Answer 4

By venipuncture from a superficial vein

Question 5

Why do you use superficial veins for blood collection?

Answer 5

• easy to locate
• vein walls are thinner than arteries
• blood pressure is relatively low so wound seals quickly

Question 6

What can you use if the veins are difficult to access for blood collection?

Answer 6

• capillary blood (finger, ear lobe etc)

- arterial puncture for efficiency of gas

Question 7

Name some functions of blood.

Answer 7

• transporting dissolved gases, nutrients, hormones and metabolic waste
• regulating pH and ion composition of fluids
• restricting blood loss at sites of injury (haemostasis) using platelets and clotting factors
• defence against toxins and pathogens using white blood ells and antibodies
• stabilising body temperature by redistributing heat

Question 8

What proteins are found in the plasma?

Answer 8

• mainly albumins (regulate osmotic pressure)
• globulins (antibodies, transport globulins)
• fibrinogen (clotting)
• 1% enzymes, hormones and pro-hormones

Question 9

What solutes are found in the plasma?

Answer 9

• organic nutrients
• electrolytes (Na+, K+, Ca2+)
• organic wastes

Question 10

What are albumins?

Answer 10

Major plasma proteins

Question 11

What do albumins do?

Answer 11

• act as molecular taxis - transporting hydrophobic molecules (fatty acids, thyroid hormones and steroid hormones)
• suck water back in to blood due to osmotic pressure - contributing to plasma osmolarity

Question 12

What do antibodies do?

Answer 12

• Aid in body defence

Question 13

What are the different regions in an antibody?

Answer 13

• Antigen binding regions
• 2 heavy chains and 2 light chains
• An Fc region that recruits immune cells through interaction

Question 14

What are transport globulins?

Answer 14

• molecules that bind small ions, hormones and compounds that might otherwise be removed by kidneys or have low solubility in water

Question 15

What are some examples of transport globulins?

Answer 15

• Hormone-binding proteins
• Metalloproteins
• Apolipoproteins
• Steroid-binding proteins

Question 16

What is the plasma called after clotting occurs/ the removal of clotting proteins?

Answer 16

Serum

Question 17

What other plasma proteins are present in the Plasma?

Answer 17

• peptide hormones (insulin and prolactin)

- glycoproteins including thyroid-stimulating hormone, follicle-stimulating hormone and leutinising hormone

Question 18

What are plasma expanders used for?

Answer 18

• increase blood volume temporarily (e.g. following blood loss after injury such as a major accident or sepsis)

Question 19

What gives blood its red colour?

Answer 19

Haemoglobin in erythrocytes

Question 20

What is the ratio of erythrocytes: platelets: leucocytes in the blood?

Answer 20

1000: 100: 1

Question 21

What is the red blood cell structure?

Answer 21

• biconcave disc
• large SA:V ratio
• forms stacks like plates through narrow vessels (rouleaux) (occur when plasma protein conc is high)
• bend and flex when entering small capillaries

Question 22

What is the red blood cell composition?

Answer 22

• lose most organelles during differentiation
• no cell division or protein synthesis
• haemoglobin >95% of the intracellular protein

Question 23

What organelle do red blood cells retain?

Answer 23

the cytoskeleton

Question 24

What is the lifespan of a red blood cell?

Answer 24

120 days

Question 25

How do erythrocytes obtain energy?

Answer 25

By anaerobic metabolism of glucose absorbed from the plasma

Question 26

What is the function of erythrocytes?

Answer 26

• transport of respiratory gases (oxygen and carbon dioxide)

Question 27

How are red blood cells formed?

Answer 27

Differentiation takes 6-8 days.

Addition of hormone EPO (erythropoietin) promotes the formation of red blood cells in the bone marrow

Question 28

What is the red blood cell turnover?

Answer 28

300 million red blood cells enter circulation per second

Question 29

What are the Blood types?

Answer 29

ABO and Rhesus blood types are based on antigen-antibody responses
A, B, AB, O

Question 30

What do each ABO blood types produce in terms of antigens and antibodies in their plasma?

Answer 30

A - produces B antibodies and A antigen
B - produces A antibodies and B antigen
AB - produces A and B antigens and no antibodies
O - produces A and B antibodies but no antigen

Question 31

What is the difference between the Rhesus and ABO Blood types?

Answer 31

Unlike ABO types, Rh - individuals do not contain anti- Rh antibodies.

Question 32

When are antibodies present in Rhesus blood types?

Answer 32

Only present if individuals sensitises by previous exposure to Rh+ blood

Question 33

What are the functions of white blood cells?

Answer 33

• defends the body against pathogens

- removes toxins, wastes and abnormal or damaged cells

Question 34

Where do white blood cells reside in?

Answer 34

Connective tissue proper or the lymphatic system

Question 35

What are the characteristics of circulating leucocytes?

Answer 35

• can migrate out of the blood stream
• are capable of amoeboid movement
• are attracted to chemotaxis ( a specific chemical stimuli)
• many are capable of phagocytosis

Question 36

What are platelets?

Answer 36

Cells that clump together at sites of injury, forming a platelet plug to prevent excessive blood loss

Question 37

What are platelets made by?

Answer 37

bone marrow megakaryocytes

Question 38

What is haemostasis?

Answer 38

• prevention of excessive blood loss upon injury ( the stopping of bleeding )

Question 39

What are the 4 phases of haemostasis?

Answer 39

1. Vasoconstriction to limit blood flow
2. Platelet plug formation
3. Coagulation (clotting) to stabilise the platelet plug
4. Fibrinolysis