Human Defence Mechanisms.

Question 0

Localised defence.

Answer 0

Phagocytosis, inflammation localising any break in the barrier and destroys invading organisms. Replacing or repairing damaged tissueZ

Question 1

Human natural barriers

Answer 1

Skin flora: a natural population of organisms which compete with bacteria for nutrients.
Blood clotting: seal wounds
Ciliated mucus membranes, stomach acid, enzymes.
LYSOZYMES DAMAGE BACTERIAL CELL WALLS.

Question 2

What is immunity?

Answer 2

A specific systemic response acquired during a lifetime.

Question 3

Natural immunity.

Answer 3

Immunity occurring after a normal infection or antibodies passed from
Mum.

Question 4

Artificial immunity

Answer 4

Injection of antigens to stimulate immune response or to stimulate combat.

Question 5

Passive immunity.

Answer 5

The body receives antibodies from another source.

Question 6

Active immunity.

Answer 6

Stimulation of immune system producing memory cells.

Question 7

Cell mediated response.

Answer 7

A virus with viral antigens, enters and infects host cell. The host cell now displays chemical markers and viral non-self antigens.patticulr t lymphocytes recognise and bind to binding sites. Thelper cells also bind releasing cytokines which stimulate cloning. Dividing rapidly by mitosis they then undergo differentiation into t killer and tmemory cells. T memory cells help lunch a futures
More rapid attack. T killer cells bind and release perforin to foreign cells.

Question 8

Humoral response.

Answer 8

Macrophage engulfs foreign material. Displays non self antigens. A b lymphocyte recognises and binds, a t helped cells does the same and releases cytokines which make the other one divide rapidly by mitosis and differentiate into n memory cells which help to launch a motor rapid attack in the future. And b plasma cells which secrete antibodies into circulation

Question 9

Antibodiesz

Answer 9

Glycoproteins - immunoglobulin group.
Produced by lymphocyte.
2 identical binding sites
Form an antigen-antibody complex.
Formed from 4 polypeptide chains
Protect body from foreign material.

Question 10

Antibody structure

Answer 10

Heavy polypeptide chain
Hinge region.
Light polypeptide chain
Antigen binding sites

Question 11

Antibodies have what function???

Answer 11

Immobilise antigens allowing destruction by phagocytosis.

Agglutinate antibodies together
Neutralise toxins produced by bacteria.

Question 12

Lymphocytes originate where. B lymphocytes mature where; activated where for t lymphocytes.

Answer 12

Stem cells in bone marrow, spleen and lymph nodes, t lymphocytes activated in tepid gland.

Question 13

Invasion by corresponding antigen causes…

Answer 13

Proliferation of t lymphocytes

Question 14

3 stages of HIV and aids.

Answer 14

Stage 1 infected person HIV+ with no symptoms. ( possible flulike symptoms pass in two week)
Stage 2 infected person feels unwell due to low t helper cell count. (thrush, herpes, pneumonia, diarrhoea)
Stage 3 aids with very low t helper cell count. ( extreme weight loss, pneumonia, chronic diarrhoea, tuberculosis, skin and lymph cancers)

Question 15

HIV structure.

Answer 15

RNA, two strands of genetic material.
Protein on outer surface allows virus to attach to human receptor cell Molecules.
Reverse transcriptase enzyme allows viral RNA to be used as a template to produce viral dna

Question 16

HIV advantages for mutation

Answer 16

Outruns immune system and targets helper t cells ad macrophages

Question 17

When do HIV use reverse transcriptase and what does it do?

Answer 17

Before inserting itself into human DNA. And allows viral RNA to be used as a template to produce viral DNA.

Question 18

HIV progression.

Answer 18

1-10 latent year period, HIV progressed to aids when body can’t fight off other opportunistic infections, like tuberculosis.
Aids victims also suffer from non Hodgkin lymphoma. And karposis sarcoma.

Question 19

How is HIV tested.

Answer 19

Antibiotics.

Question 20

Vaccination forms.

Answer 20

A vaccine may be an attenuated or killed form of pathogen. Or an inactive toxin from a bacteria.

Question 21

What is vaccination a medical example of?

Answer 21

A preventative medicine. Of top few are vaccinated then there will be an epidemic, if lots do the the pathogen will likely die out.

Question 22

Draw the vaccine graph.

Answer 22

First response lasts 5 days

Time gap between exposures. Secondary response lasts 5 days and jumps up on two.

Question 23

Properties of secondary response.

Answer 23

Lower level of antigen, shorter latent period. Higher concs of antibodies produced and duration of concs is longer.

Question 24

Each subsequent exposure acts as a what?

Answer 24

A booster until max levels are reached.