Health and Disease

Question 1

How does a pathogen cause disease?

Answer 1

1. The pathogen must travel from one host to another.
2. The pathogen gets into the host’s tissues.
3. The pathogen reproduces.
4. The pathogen will cause damage to the host’s tissues.

Question 2

What does HIV stand for and what causes it?

Answer 2

Human Immunodeficiency Virus caused by a virus that infects the T lymphocytes.

Question 3

How is HIV transmitted?

Answer 3

Through blood, breast milk, semen and vaginal fluid.

Question 4

How can the risk of contracting HIV be increased?

Answer 4

Unprotected penetrative sex, breast feeding, blood transfusions and exchanging needles.

Question 5

What can’t HIV be transmitted through?

Answer 5

Kissing, hugging, shaking hands or sharing food utensils.

Question 6

What does TB stand for and what is it caused by?

Answer 6

Tuberculosis and is caused by Mycobacterium tuberculosis.

Question 7

How is TB transmitted?

Answer 7

Inhaling water droplets that have been coughed or sneezed out by an infected person.

Question 8

How are people more at risk of contracting TB?

Answer 8

Not vaccinated against TB, homeless or malnourished, overcrowded home, consume milk or meat from infected cattle, poor ventilation, weakened immune system or prolonged contact.

Question 9

How is Malaria spread and what is it caused by?

Answer 9

female Anopheles mosquito. Caused by Plasmodium

Question 10

How does malaria make someone ill?

Answer 10

When the mosquito bites an uninfected person, she injects saliva into the blood stream, which contains the Plasmodium.

Question 11

How are people more at risk of getting malaria?

Answer 11

Fail to sleep under a mosquito net, not take antimalarial drugs, wear short-sleeved shirts/shorts or fail to wear insect repellent spray.

Question 12

Where is malaria found?

Answer 12

Tropical regions

Question 13

How many people are killed from malaria and how many prevalences are there?

Answer 13

3 million people annually. 300 million people

Question 14

Where is HIV most common?

Answer 14

Sub-Saharan Africa, but spreading into a pandemic.

Question 15

How many people incidents are there of HIV?

Answer 15

5 million people each year

Question 16

How many people are living with HIV?

Answer 16

45 million people.

Question 17

How many people have died from HIV ?

Answer 17

30 million

Question 18

How many incidents of TB are there?

Answer 18

1% of population each year

Question 19

How many people are living with TB?

Answer 19

30%of the worlds population

Question 20

How many people have died from TB?

Answer 20

1.6 million per year.

Question 21

Name 5 examples of primary defences.

Answer 21

Tears
Skin
Urine
Vagina
Respiratory system

Question 22

How do tears act as a primary defence?

Answer 22

Lysozymes in tear secretions are antimicrobial

Question 23

How does skin act as a primary defence?

Answer 23

Acts as a physical barrier to micro-organisms and skin flora outcompetes pathogenic microorganisms.

Question 24

How does the Urine act as a primary defence?

Answer 24

Urine in the urethra is an antimicrobial.

Question 25

How does the respiratory system act as a primary defence?

Answer 25

Mucus lining the respiratory system traps microorganisms and cilia moves them to the back of the throat.

Question 26

How does the vagina act as a primary defence system?

Answer 26

An acidic environment prevent the growth of pathogens.

Question 27

Describe the process of phagocytosis.

Answer 27

1. The phagocyte has a receptor on its CSM and detects the antigen on the pathogen. 2. They become attached. 3. Pathogen is engulfed by infolding or phagocyte membrane. Become a phagosome. 4. Lysosomes release lysins into the phagosome which breaks down the pathogen. 5. The products are moved out of the cells my exocytosis.

Question 28

How are lymphocytes activated after phagocytosis?

Answer 28

Macrophages releases a chemical (histamine) which makes the the capillaries more leaky and so more fluid leaves the area of infection, so more tissue fluid passes into the lymphatic system.

Question 29

What two processes do antibodies undergo?

Answer 29

Neutralisation and Agglutination.

Question 30

What is the difference between T-helper cells and T-killer cells?

Answer 30

T-helper cells produce cytokines that stimulate the B-cells to develop. T-killer cells bond to cells carrying the antigen and produce toxic chemicals which kill the infected body cells.

Question 31

Compare and contrast the primary and secondary immune response.

Answer 31

Primary- Starts to produce antibodies, which takes a few days. Memory cells are also produced. Secondary- Recognises the pathogen, and antibodies are produced more rapidly.

Question 32

An example of natural passive immunity.

Answer 32

Antibodies provided via the placenta or the breast milk.

Question 33

An example of natural active immunity.

Answer 33

Provided by antibodies made as a result of an infection. Chicken pox.

Question 34

An example of artificial passive immunity.

Answer 34

Immunity provided by injection of antibodies made by another individual. Tetanus

Question 35

An example of artificial active immunity.

Answer 35

Provided by antibodies made in the immune system as a result of vaccination. Injected with a weakened, dead to similar pathogen. TB and Influenza.

Question 36

What is a herd vaccination?

Answer 36

Vaccinate the whole population in order to prevent a disease form spreading.

Question 37

What is a ring vaccination?

Answer 37

Used whenever a new disease breaks out. Also used to prevent disease against feedstock.

Question 38

How are new medicinal drugs discovered?

Answer 38

Accidentally From traditional medicine Observation of wildlife Research