Chapter 12- Communicable Dieseas

Question 1

Non specific defences- keeping pathogens out

Answer 1

Skin covers the body and prevents entry of pathogens
Lined with mucous membranes, that seceret sticky mucus
Lysosomes in tears and urine

Question 2

Blood clotting

Answer 2

If you cut yourself, the skin is breached and pathogens can enter the boy. Blood clots rapidly to seal the wound. When platelets come into contact with collagen in skin or wall of damaged blood vessel, that adhere and begin to secrete several substances.

Question 3

Inflammatory response

Answer 3

Localised response to pathogens resulting in inflammation at the site of wound
Mast cells are activated in damaged tissue and release chemicals in histamines and cytokines
Histamines make the blood vessels dilate and vessels more leaky
Cytokines attract white blood cells

Question 4

Non specific defences- getting rid of pathogens

Answer 4

Fevers

Phagocytosis

Question 5

What are phagocytes?

Answer 5

Specialised white cells that engulf and destroy pathogens. There are two main types of phagocytes- neutrophils and macrophages.

Question 6

Stages of phagocytosis

Answer 6

1. Pathogens produce chemicals that attract phagocytes
2. Phagocytes recognise non human proteins on the pathogen
3. The phagocyte engulfs the pathogen and encloses it im a vacuole known as a phagosome.
4. The phagosome combines with a lysosome to form a phagolysosome
5. Enzymes from the lysosome digest and destroy the pathogen

Question 7

What are opsonins

Answer 7

Chemicals that bind to a pathogen and tag them so they can be more easily recognised

Question 8

Where do B lymphocytes mature?

Answer 8

Bone marrow

Question 9

Where do T lymphocytes mature?

Answer 9

Thymus gland

Question 10

T helper cells

Answer 10

Cell receptors on their cell surface membrane . They produce interleukins which stimulate the activity of B cells, which increases antibody production.

Question 11

T killer cells

Answer 11

Destroy the pathogen carrying antigen. They produce a chemical called perforin, which kills the pathogen by making holes in its membrane.

Question 12

T memory cells

Answer 12

These live for a long time and are part of the immunological memory. If they meet a antigen the second time they divide rapidly to form a huge number of T killer cells

Question 13

T regulator cells

Answer 13

Cells suppress the immune system acting to control and regulate it.

Question 14

Main type of B lymphocytes

Answer 14

Plasma cells
B effector cells
B memory cells

Question 15

Plasma cells

Answer 15

These produce antibodies to a particular antigen and release them into the circulation.

Question 16

B effector cells

Answer 16

Divide to form plasma cell clones

Question 17

B memory cells

Answer 17

These live for a long time and provide the immunological memory

Question 18

Humoral immunity

Answer 18

Interleukins produced by activated T helper cells
The activated B cells divide by mitosis to give clones of plasma cells and B memory cells
Cloned plasma cells produce antibodies that disable the antigens , known as primary immune response
Some cloned B cells can develop into b memory cells. Perform part of secondary immune response

Question 19

Difference between natural and artificial immunity

Answer 19

Natural is where you meet a pathogen for the first time, your immune system is activated and antibodies are formed, which results in the destruction of the antigen
Artificial is where the disease is killed before their immune system makes the antibodies they need.

Question 20

Artificial passive immunity

Answer 20

Gives temporary immunity is where antibodies are formed in one individual, extracted and then injected into the bloodstream of another individual

Question 21

Artificial active immunity

Answer 21

The immune system of the body is stimulated to make its own antibodies to a safe form of an antigen, which is injected into the bloodstream

Question 22

Examples of antibodys actions

Answer 22

Opsonins-tag pathogens for better recognition
Agglutinins-stick pathogens together for better recognition
Antitoxins-neutralize toxins released by pathogens