Cell Mediated Immunity

Question 1

what is the primary immune response?

Answer 1

-immunity which is the ability of organisms to resist infection by protecting agains disease causing microorganisms or their toxins that invade their bodies in living the recognition of foreign materials

Question 2

what are antigens?

Answer 2

• an antigen is any part of an organism or substance that is recognised as non self by the immune system and stimulate an immune response
• antigens are usually proteins that are part of the cell surface membranes or cell walls of invading cells such as microorganisms or abnormal body cells like cancer cells
• the presence of an antigen triggers the production of an antibody as part of the body’s defence system

Question 3

what are lymphocytes?

Answer 3

• immune responses such as phagocytosis are non specific and occur Whatever the infection
• the body also has specific responses that react to specific antigens, it’s slow at first but can provide long term immunity
• this specific immune response depends on a type of white blood cell called a lymphocyte
• lymphocytes are produced by stem cells in bone marrow

Question 4

what are B lymphocytes?

Answer 4

• they mature in the bone marrow
• they are associated with humoral immunity which involves antibodies that are present in body fluids it humour like blood plasma

Question 5

what are T lymphocytes?

Answer 5

-they mature in the thymus gland and are associated with cell mediated immunity which involves body cells

Question 6

what is cell mediated immunity?

Answer 6

• they respond to an organisms own cells that have been infected by non self material from a different species like a virus
• they respond to cells from other individuals of the same species because these are genetically differ et
• therefore they have differ met antigens ok their cell surface meme tame from the antigens in the organisms own cells

Question 7

how do T lymphocytes distinguish between invader cells and normal cells?

Answer 7

• phagocytes that have engulfed and hydrolysed a pathogen present some of a pathogens antigens on their own cell surface membrane
• body cells invaded by a virus present some of the viral antigens on their own cell surface membrane
• transplanted cells from individuals of the same species have different antigens in their cell surface membrane
• cancer cells are different from normal body cells and present antigens on their cell surface membranes

Question 8

what are antigen presenting cells?

Answer 8

-cells that display foreign antigens on their surface because they can premarital antigens of other cells in their own cell surface membrane

Question 9

what is the cellular response?

Answer 9

-cell mediated immunity

Question 10

how do T lymphocytes respond to infections?

Answer 10

• pathogens invade body cells or are taken in by phagocytosis
• the phagocyte places antigens from the pathogen on its cell surface membrane
• receptors on the specific helped T cell fits exactly onto these antigens
• this attachment activates the T cell to divide rapidly by mitosis and for a clone of genetically identical cells

Question 11

how do cytotoxic T cells kill infected cells?

Answer 11

• cytotoxic T cells produce a protein called performing that makes hikes in the cell surface membrane
• these holes mean the cell membrane becomes freely permeable to all surfaces and the cell does as a result
• which illustrated the vital importance of cells surface membranes in maintaining cell integrity
• viruses use living cells to replicate so body cells are sacrificed to prevent the virus multiplying and infecting more cells

Question 12

What do cloned T cells do?

Answer 12

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