Chapter 12 - Immunity

Question 1

What are the 4 different types of T lymphocyte?

Answer 1

1. T helper cell
2. T killer cell
3. T memory cell
4. T regulatory cell

Question 2

What are the 3 different types of B lymphocyte?

Answer 2

1. B effector cell
2. Plasma cell
3. B memory cell

Question 3

Where are lymphocytes produced?

Answer 3

stem cells in the bone marrow of long bones and sternum.

Question 4

What are lymphocytes?

Answer 4

• small white blood cell

Question 5

Where are the lymphocytes kept?

Answer 5

in lymph nodes

Question 6

How do the lymphocytes travel around the body?

Answer 6

through the bloodstream

Question 7

What is the site of maturation for T lymphocytes?

Answer 7

thymus gland

Question 8

What is the site of maturation for B lymphocytes?

Answer 8

bone marrow

Question 9

Function of T helper cells

Answer 9

have CD4 receptors on cell surface membrane - bind to receptors on APC
produce interleukins (type of cytokine) which:
- stimulate activity of B lymphocytes,
- stimulates the production of other types of T lymphocytes,
- attracts and stimulates macrophages to ingest pathogens.

Question 10

Function of T killer cells

Answer 10

kill the infected host cell.
destroy pathogen carrying antigen.
produce perforin - makes holes in the cell surface membrane of pathogen.

Question 11

Function of T memory cells

Answer 11

form part of immunological memory

Question 12

Function of T regulatory cells

Answer 12

suppress the immune system (stops the production of Ig in B lymphocytes.)
stop immune response once the pathogen is eliminated
make sure body recognises self-antigens

Question 13

Function of B effector cells

Answer 13

divide by mitosis to form plasma cell clones

Question 14

function of plasma cells

Answer 14

produce antibodies

Question 15

function of B memory cells

Answer 15

provide immunological memory

Question 16

What is cell mediated immunity?

Answer 16

An immune responce that doesnt involve antibodies. Involves the activation of phagocytes, antigen specific cytotoxic T-lymphocytes and the release of various cytokines.

Question 17

What happens in cell mediated immunity?

Answer 17

1. macrophages and dendritic cells in lymph nodes engulf pathogens by exocitosis.
2. They digest the pathogens by phagocytosis.
3. Macrophages and dendritic cells process the antigens and become antigen presenting cells by exposing the antigens on their cell surface membrane.
4. Receptors on some T helper cells are complementary to antigens on the antigen presenting cells.
5. complementary ones bind to the APC = clonal selection.
6. T helper cells are activated and produce interleukins
7. these stimulate rapid mitosis for the t cells to form clones = clonal expansion