5.3 - T Lymphocytes And Cell - Mediated Immunity

Question 1

What is the deffiniton of immunity?

Answer 1

The ability of organisms to resist infection by protecting against disease-causing microorganisms or their toxins that invade our bodies

Question 2

What is the definition of an antigen?

Answer 2

Any part of an organism or substance that is recognised as non-self (foreign) by the immune system and stimulates an immune response.

Question 3

What type of white blood cells are involved in non specific response?

Answer 3

Phagocytes

Question 4

What type of white blood cells are involved in a specific response

Answer 4

Lymphocytes

Question 5

Where are T cells made?

Answer 5

Bone marrow

Question 6

Where are T cells matured?

Answer 6

Thymus gland

Question 7

What do lymphocytes resond to?

Answer 7

1. An organisms own cells that have been infected by non - self material from a different species (virus)
2. Cells from other individuals of the same species because these are genetically different

Question 8

T cells can distinguish invader cells from normal cells because?

Answer 8

1. Phagocytes that have engulfed and hydrolysed a pathogen present some of a pathogens antigens on their on surface membrane
2. Body cells invaded by a virus present some of their own viral antigens on their own cell-surface membrane
3. Transplanted cells from individuals of the same species have different antigens on their surface membrane
4. Cancer cells are different from normal body cells and present antigens on their surface membranes

Question 9

Cells that display foreign antigens on their surface are called what?

Answer 9

Antigen presenting cells

Question 10

T lymphoctes will only respond to what?

Answer 10

Antigens that are presented on a body cell (rather than to antigens within the body fluids)

Question 11

Give the stages of the response of the T cells to infection by a pathogen:

Answer 11

1. Pathogens invade body cells or are taken up by phagocytes
2. Phagocyte presents antigens on their surface membrane
3. Receptors on a specific helper T cell fit exactly onto these antigens
4. This attachment activates the T cell to divide rapidly by mitosis and form a clone of genetically identical cells

Question 12

What do the cloned T cells do?

Answer 12

A - develop into memory cells that enable a rapid response to future infections by the same pathogen
B - stimulate phagocytes to engulf pathogens by phagocytosis
C - stimulate B cells to divide and secrete their antibodies
D - activate cytotoxic T cells

Question 13

What protein do killer T cells produce?

Answer 13

Perforin

Question 14

What does perforin do?

Answer 14

Makes holes in the cell surface membrane causing the cell to die