First line of defence

Question 1

What are communicable diseases caused by and how are they transmitted

Answer 1

Caused by micro-organisms, usually bacteria, viruses, fungi, protozoa, transmitted from one person to another

Question 2

What is a pathogen

Answer 2

Disease-causing organism

Question 3

Non-specific/generalised defence

Answer 3

Response to all infection or injuries

Question 4

Specific defence

Answer 4

Works against selected pathogens

Question 5

Bacteria

Answer 5

A single cell organism that may or may not be pathogenic

Question 6

Types of bacteria

Answer 6

Cocci, Bacilli, Spirilla, Vibrio

Question 7

Diseases caused by bacteria

Answer 7

Valley fever, Rat-bite fever, Vibriosis and cholera

Question 8

Virus

Answer 8

An infectious agent consisting of a protein coat surrounding a core of nucleic acid

Question 9

Bacteriophage

Answer 9

A virus that infects bacteria

Question 10

Examples of viruses

Answer 10

Monkeypox, COVID, Chickenpox

Question 11

6 ways pathogens can be transferred

Answer 11

Contact, bodily fluids, droplets, contaminated food/drink, airborne transmission, by vectors

Question 12

Transmission by contact through indirect or direct means

Answer 12

Involves the spread of pathogens by touching an infected person of an object they have touched, E.g- STI’s such as chlamydia

Question 13

Transfer of bodily fluids

Answer 13

When blood or other body fluids (saliva, mucus) from an infected person comes into contact with mucus membranes (nose, mouth) or the bloodstream of an uninfected person, E.g- HIV, Hep B and C

Question 14

Infection by droplets

Answer 14

When tiny droplets of moisture that have pathogens in them are breathed in by uninfected people (still has moisture), E.g- COVID, Flu

Question 15

Ingestion of contaminated food or drink

Answer 15

Food or drink contaminated with pathogens is ingested, E.g- Salmonella

Question 16

Airborne transmission

Answer 16

When moisture in exhaled droplets evaporates, some pathogens remain and can be inhaled (no moisture left), E.g- Cold

Question 17

Transmission by vectors

Answer 17

The transfer of pathogens by other animals such as insects, E.g- Malaria, Rabies

Question 18

3 lines of defence

Answer 18

Keep microbes out of body, Non-specific attack on microbes, Specific attack on microbes

Question 19

What is the first line of defence

Answer 19

Prevents entry and reproduction of pathogens in the body

Question 20

What structures prevent the entry of pathogens

Answer 20

External defences and protective reflexes

Question 21

Why isn’t the first line of defence always successful

Answer 21

Burns and cuts to the skin reduce the effectiveness of the first line of defence

Question 22

Chemical external defences (4)

Answer 22

Cerumen, acids, lysozyme, skin

Question 23

Cerumen

Answer 23

Ear wax, slightly acidic, contains lysozyme that kills bacteria

Question 24

Acids

Answer 24

Acid kill bacteria

Question 25

Lysozyme

Answer 25

Enzyme that kills bacteria

Question 26

Skin as a chemical defence

Answer 26

Sebum kills bacteria, Sweat contains salts and fatty acids and prevents growth of micro-organisms

Question 27

Mechanical external defences (4)

Answer 27

Mucous membranes, hairs, flushing action, skin

Question 28

Mucous membranes

Answer 28

Secretes mucus that traps particles, Inhibit micro-organisms from entering

Question 29

Hairs

Answer 29

Hair and layer of mucus traps up to 90% of particles

Question 30

Flushing action

Answer 30

Flushing of body fluids helps to keep some areas relatively free from pathogens

Question 31

Skin as a mechanical defence

Answer 31

Barrier

Question 32

4 protective reflexes

Answer 32

Sneezing, coughing, vomiting, diarrhoea

Question 33

Sneezing

Answer 33

Caused by irritation on the walls of the nasal cavity by noxious fume or dust that carries micro-organisms, Forceful expulsion of air carries mucus, foreign particles and irritating gases out

Question 34

Coughing

Answer 34

Irritation in the lower respiratory tract (bronchi and bronchioles), Air forced from lungs moves irritant out and up the trachea

Question 35

Vomiting

Answer 35

Caused by psychological stimuli, excessive stretching and bacterial toxins, Contraction of abdomen muscles and diaphragm expels stomach contents

Question 36

Diarrhoea

Answer 36

Caused by irritation of small and large intestine by bacteria, viruses or protozoa's, Irritation causes increased contractions of the muscles in the wall of intestine meaning material doesn't stay in the large intestine to absorb enough water