Immunity

Question 1

Primary defences (non specific)

Answer 1

Skin - top layer → keratinocytes dry out, leave keratin waterproof barrier
Produces oil called - sebum contains enzyme - lysozyme
Hairs- trap pathogens
Tears contain lysozyme
Mucus membranes - contains ciliated epithelium - made of goblet cent → cilia → mucus plug in vagina
Expulsive-reflexes - coughing and sneezing

Question 2

Secondary defences (non specific)

Answer 2

• Phagocytosis
• good clotting
• inflammation

Question 3

Phagocytes

Answer 3

1. Neutrophils
   - made in bone marrow
   - multi lobed nuclei - helps flexible
   - In blood + tissue fluid (only in infection)
2. Macrophage
   - made in bone marrow
   - larger
   - in body organs, / lymph nodes
   - travel in blood known as monocytes (still macrophage but in blood so diff name),
   - dendritic cells are macrophages which are found in peripheral tissue

Question 4

Blood clotting

Answer 4

Exposed collagen → clotting factors
l

Question 5

Antibodies

Answer 5

Produced by plasma cells
Large immunoglobulins
They are complementary to a specific antigen
3 types
Opsonins - attach to antigens on the surface of a pathogen, help the phagocyte to bind to and engulf the pathogen, it can also stop the pathogen from binding to any new host cells ( neutralisation)
Agglutinins - each antibody has 2 binding sites so can bind to more than one pathogen at a time, this cross links pathogens together creating a clump (agglutinating them)
Anti - toxins - pathogens sometimes release toxins, these can be neutralised by anti toxin

Question 6

Secondary response

Answer 6

B and T memory cells go through clinal selection and expansion and differentiation more quickly
Antibodies are produced faster and in greater number
You have immunological memory

Question 7

Autoimmune diseases

Answer 7

Is when the immune system attacks the body itself
Early in development, Band T cells specific to our own antigens are destroyed
Why our body starts to attack itself is generally unknown but can be linked to both environmental and genetic factors
Examples
Lupus
Arthritides
Vitiligo
Type 1 diabetes

Question 8

Herd vaccination

Answer 8

Is when you vaccinate to ensure that all or almost all of the population are immune (they achieved herd immunity)
Almost all would need to be vaccinated (e.g. measles requires 95%% to be vaccinated

Question 9

Ring vaccination

Answer 9

When a new disease occurs in the population,everyone in proximity must be vaccinated
This could be some households,a village or town

Question 10

Traditional medicines

Answer 10

Thousands of plants are used for traditional medicine globally
Most modern medicines are derived from traditional medicine (e.g morphine is from poppy seeds)

Question 11

Antibiotics

Answer 11

Prevent the growth of bacteria
Broad spectrum antibiotics can kill a range of bacteria
As soon as we discovered antibiotics the human population increased exponentially

Question 12

Personalised medicine

Answer 12

Screening genomes can help to identify potential new drugs
We could screen the genome of a person with a particular disease and develop a drug that will be specific to that person