5. defence against parasitic attack

Question 1

what does immune response have?

Answer 1

Immune response in mammals has both non-specific and specific aspects

Question 2

what are the non specific defences?

Answer 2

Physical barriers, chemical secretions, inflammatory response, phagocytes, and natural killer cells destroying cells infected with viruses are examples of non-specific defences

Question 3

what are the specific cellular defences?

Answer 3

A range of white blood cells constantly circulates, monitoring the tissues

Question 4

what happens if tissues become damaged?

Answer 4

If tissues become damaged or invaded, cells release cytokines that increase blood flow resulting in non-specific and specific white blood cells accumulating at the site of infection or tissue damage

Question 5

what do mammals contain?

Answer 5

Mammals contain many different lymphocytes, each possessing a receptor on its surface, which can potentially recognise a parasite antigen

Question 6

what produces a clonal population?

Answer 6

Binding of an antigen to a lymphocyte’s receptor selects that lymphocyte to then divide and produce a clonal population of this lymphocyte

Question 7

what do selected lymphocytes do?

Answer 7

Some selected lymphocytes will produce antibodies, others can induce apoptosis in parasite-infected cells

Question 8

what do antibodies have?

Answer 8

Antibodies possess regions where the amino acid sequence varies greatly between different antibodies

Question 9

what gives specificity?

Answer 9

This variable region gives the antibody its specificity for binding antigen

Question 10

what happens when the antigen binds?

Answer 10

When the antigen binds to this binding site the antigen-antibody complex formed can result in inactivation of the parasite, rendering it susceptible to a phagocyte, or can stimulate a response that results in cell lysis

Question 11

what is also formed?

Answer 11

Memory lymphocyte cells are also formed