Blood

Question 1

Define blood

Answer 1

Blood is a fluid that delivers necessary substances such as nutrients and oxygen to cells, and transports waste products away from cells

Question 2

Describe the composition of blood

Answer 2

Cellular elements
1) Erythrocytes (RBC)
2) Leukocytes (WBC)
3) Platelets (cell fragments)
Plasma:
1) water
2) proteins
3) solutes

Question 3

What is plasma

Answer 3

Complex liquid consisting of large number of organic and in-organic molecules

Question 4

What are organic solutes

Answer 4

Plasma proteins, nutrients, glucose; lipids; vitamins, metabolic end products (waste)

Question 5

What are the 3 groups plasma proteins are classified into

Answer 5

1) Albumins: blood viscosity, acts as buffer, transfer of fatty acids and thyroid hormones
2) Globulins: transport lipids, carbohydrates, hormones, ions
3) Fibrinogens: function in blood clotting

Question 6

What are inorganic components

Answer 6

Electrolytes: involved in osmosis, Na+, K+, Ca+, Mg2+, Cl-, SO42-, HPO42-

Question 7

Describe red blood cells

Answer 7

• Transports oxygen from lungs to tissues of the body & transport carbon dioxide from tissues to the lungs
• Produced in bone marrow
• Incomplete cells: no nuclei, unable to synthesise new proteins, cannot reproduce, cannot maintain structure long term, cells age & die

Question 8

What is the diameter of a red blood cell

Answer 8

7μm in diameter

Question 9

What is haemoglobin

Answer 9

The protein responsible for O2 transport, CO2 transport, & buffering

Question 10

What is sickle cell anaemia

Answer 10

• genetic mutation causing abnormal haemoglobin
• results in blockage of capillaries&raquo_space; tissue damage; destruction of deformed erythrocytes&raquo_space; anaemia

Question 11

Where are leukocytes produced and what is their function

Answer 11

Produced in bone marrow.
They are cells of the immune system & provide defence against foreign cells ( bacteria, foreign matter). They use blood as transportation & enter tissue to perform function.

Question 12

What is the function of neutrophils

Answer 12

Phagocytosis - ingestion & destruction of particulate material

Question 13

What are the characteristics of platelets

Answer 13

• Cell fragments lacking nuclei
• Originate from bone marrow
• Life span ~ 10 days
• Forms platelet plugs & releases chemical necessary for blood clotting

Question 14

The mechanism that predominates when it comes to minimising blood loss depends on…

Answer 14

• kind & number of vessels damaged
• location of injury

Question 15

What are the prerequisites for bleeding

Answer 15

Loss of vessel continuity
Marked increase in permeability of vessels (Fluid leaks out)
Pressure inside vessel greater than outside

Question 16

What are the prerequisites for haemostasis

Answer 16

Pressure difference favouring blood loss is eliminated
Damaged portion of vessel is sealed

Question 17

Describe blood clotting

Answer 17

• Initially when blood vessel is damaged, vessel wall contracts & slows blood flow to damaged vessel
• Platelets adhere to collagen fibres in the wall of damaged vessel
• More platelets attracted & form a plug
• More permanent blood clot forms in time
• Coagulation

Question 18

Describe coagulation

Answer 18

Blood clot forms consisting of an insoluble fibrous protein called Fibrin which forms long threads of webbing in which blood cells, platelets and plasma become trapped

Question 19

What mechanism causes antibodies to combine with an antigen

Answer 19

Lock & Key mechanism (certain antigens)