Unit 4 Flashcards

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1
Q

What is immunity

A

the ability of the body to resist infection by a pathogen

or to destroy the organism if it succeeds in invading and infecting the body

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2
Q

What are the two types of immunity?

A

non specific

specific

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3
Q

what is a pathogen?

A

a micro organism that causes disease (fungi, bacteria, virus)

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4
Q

what is an antigen?

A

proteins on the surface of cells.

used as a marker to identify a particular cell type

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5
Q

The First Line of Defence

A

epithelial cell, which form your skin, provide the first line of defence against pathogens provided they remain in tact. the form a physical barrier.

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6
Q

Chemical Defence (1)

A

secretions from the sebacous glands and sweat glands in the skin. keep the pH level that is too low for most pathogens

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7
Q

Chemical Defence (2)

A

tears and saliva contain the enzyme lysozyme which digest the cell wall of bacterial cells

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8
Q

Chemical Defence (3)

A

cells in the mucous membrane secrete sticky mucus that traps microorganisms

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9
Q

Chemical Defence (4)

A

the epithelial cells in the stomach release acid which destroys microorganisms that have been swallowed

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10
Q

Secondary line of defence - inflammatory response

A

when the body suffers physical injury it will respond with a localised defence called an inflammatory response

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11
Q

what are phagocytes?

A

white blood cells that engulf and digest bacteria in a process called phagocytosis

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12
Q

What do MAST Cells do?

A

release histamine causing vasodilation in blood vessels

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13
Q

what do cytokines do?

A

signalling molecules which stimulate recruitment of other cell types

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14
Q

Phagocytes

A

engulf pathogens and clean up the injured site

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15
Q

Anti microbial proteins

A

amplify the immune response

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16
Q

Clotting Elements

A

coagulation of blood helps to prevent further infection and starts tissue repair

17
Q

Stages of inflammatory response

A
  • Physical injury
  • mast cells activated and release histamine
  • histamine stimulates vasodilation of the blood vessels in injured site
  • blood vessels become more permeable leak fluid into neighbouring tissues causing swelling
  • cytokines secreted
  • migration of phagocytes to injured area/migration of antimicrobial proteins to injured area/delivery of blood clotting factors
18
Q

Natural Killer Cells

A

stimulate infected cells to commit suicide. apoptosis. infected cells are stimulated to produce a self destructive enzyme.
release cytokines that stimulate a specific immune response

19
Q

Specific Immunity

A

targets one particular pathogen.

involves T & B Lymphocytes

20
Q

Immune Surveillance

A

range of white blood cells move around body & constantly monitor the state of tissue.
if damage or invasion of microbes detected, white blood cells detect and release cytokines

21
Q

Antigens

A

any foreign molecule that is recognised by the immune system and produces a response from a lymphocyte.

22
Q

Antigenic Receptors

A

each lymphocyte has several copies of a single type of antigen receptor on the surface of the membrane.
lymphocyte specific to one antigen.

23
Q

Clonal Selection Theory

A

once lymphocyte detected.

dividing repeatedly to form a clonal population of identical lymphocytes

24
Q

Lymphocytes respond specifically to

A

Antigens on foreign cells
cells infected by pathogens
toxins released by pathogens

25
Q

Autoimmunity

A

autoimmune disease are a result of failure in regulation of the immune system leads to a T-Lymphocyte immune response to self cells

26
Q

Allergic Reaction

A

B Lymphocytes becoming hypersensitive to a normally harmless antigen
triggers an immune response which sensitises to the allergen.

27
Q

Helper T cells

A

secrete cytokines that activate phagocytes, cytotoxic t cells and B lymphocytes.
specific HTC then binds to the antigen on the antigen presenting cell.
HTC becomes activated & divides to produce a clone of activated helper cells.

28
Q

Cytotoxic T Cells

A

detect & destroy infected cells by several methods including apoptosis.

29
Q

Antigen Presenting Cells

A

after a phagocyte destroys an invading pathogen it presents fragments of its antigens on its cell surface.
phagocyte now referred to as an antigen presenting cell

30
Q

B lymphocytes

A
  • the presence of an antigen triggers the production of antibodies by B Lymphocytes.
  • An Antibody is a y-shaped protein, with each arm having a receptor that is specific to one antigen
  • Antibody production by B Lymphocytes can occur following direct contact between the B cell & antigen
  • B Cell displays molecules of foreign antigen it has taken in.