physical and chemical barriers Flashcards Preview

Health, Disease and the Development of Medicine - BIOLOGY > physical and chemical barriers > Flashcards

Flashcards in physical and chemical barriers Deck (20):
1

give an example of a physical barrier

skin

2

how can a pathogen pass a physical barrier?

through wounds

by an animal vector that pierces the skin

3

what additional defence does the skin have?

glands that produce secrete substances - lysozyme

4

what does lysozyme do?

breaks down the cell walls of some types of bacteria

5

why is skin a physical barrier?

pathogens have difficulty getting past it

6

why is lysozyme a chemical defence?

it reacts with substances in the pathogen which kills them or makes them inactive

7

where is lysomzyme secreted from?

tears(in eyes)

saliva(in mouth)

mucus - protects thinner surfaces of the body

8

what is mucus?

sticky secretion produced from cells lining openings - mouth and nose - that pathogens could use to enter the body

9

what gets trapped in mucus?

dust and pathogens

10

what are the cells that line the nose and tubes in the breathing system?

cilia

11

how are cilliated cells specialised and how is this helpful?

they move substances such as mucus across their surfaces

helps carry dust and pathogens away either out of the body or into the throat where they enter the digestive system

12

where does substances that you swallow pass down?

oesophagus (gullet) then into the stomach

13

what do some cells in the stomach produce and what does it reduce?

secrete hydrochloric acid

reduce pH to 2

14

what does the acidity of the stomach do to pathogens?

destroy them

15

name 2 STIs

HIV virus

chlamydia bacterium

16

how are STIs spread?

through contact with sexual fluids - e.g.semen or vaginal fluids

passed from mother to baby - could harm baby

sharing needles when injecting drugs

17

how can you reduce the or prevent STIs?

artificial barrier - condom

18

how do you indentify STIs?

screening

19

why have the number of chlamydia diagnosis increased?

possibly due to more screening

20

why is blood checked before transfusion to another patient?

to make sure it doesn't contain HIV particles or other pathogens