The Immune System

Question 1

What are non-specific defences? (innate

Answer 1

• Skin, mucous membranes etc

- Inflammatory Response (body temperature, neutrophils, macrophages, attack cells)

Question 2

What are specific defences?

Answer 2

Antibodies, B and T lymphocytes, T helper cells

Question 3

Describe B-lymphocytes

Answer 3

They are produced in the bone marrow and produce antibodies. Memory B-cells produce specific antibodies. They are part of the humeral response

Question 4

Describe T-lymphocytes

Answer 4

They are produced in bone marrow and cause cell death in damaged cells (infection, cancer). They also produce killer T-cells. They are part of the cell mediated response.

Question 5

Describe T helper cells

Answer 5

They activate killer t cells, macrophages and antibody producing B cells. They are activated by antigen presenting cells.

Question 6

Describe features of innate immunity

Answer 6

• Phagocytes
• Natural killer cells
• Inflammation
• Leukocytosis

Question 7

Describe features of humeral immunity

Answer 7

Slower to act, requires antigen exposure and systemic not specific. Creates memory.

Question 8

What is complement?

Answer 8

Serum proteins that are involved in:

• inflammation
• cell death
• opsonisation
• bacterial infections
• autoimmune disases

Question 9

What is opsonisation and why is it important?

Answer 9

Binding of opsonin (e.g. antibody) and attraction of macrophages. Important as pathogens are negatively charged and this allows them to get close.

Question 10

Why does lymphodema not pit?

Answer 10

Subcutaneous

Question 11

Describe tissue fluid formation

Answer 11

To do with balance between oncotic and hydrostatic pressures. The net difference is +10 at arterial end so nutrients move out but -10 at venous end so waste products move back in. In the middle the forces are equal.