B5 - Communicable Diseases Flashcards
1
Q
Non specific defence systems in the human body and their role
A
- Skin - forms a protective layer covering the body. Outer cells are dead which are hard to penetrate. Sebum kills bacteria. Scabs
- Nose - hair + mucus which trap pathogens
- Cilia - in trachea which trap pathogens and sweep them up to be swallowed
- Stomach - HCl acid which kills pathogens
- Tears produced by tear ducts contain enzymes which kill bacteria and are antiseptic
2
Q
Roles of the immune system
A
- Destroys pathogens and the toxins they produce
- Protects us if the same type of pathogen enters the body again
3
Q
Role of phagocytes
A
- Engulf and destroy pathogens using enzymes through phagocytosis
4
Q
What are antibodies and their role
A
- Protein molecules produced by lymphocytes - they are specific to the antigen
- They attach onto pathogen antigens
- This renders them useless as they can’t attach to cells and they clump together
- They remain in the blood for a long time as memory cells after the infection and can give a more rapid response if pathogens re-enter
5
Q
What is a pathogen
A
Microorganisms that cause infectious disease
This can include bacteria, protists, viruses or fungi
6
Q
How do bacteria damage the human body
A
- Once in the body, they reproduce rapidly
- They then release toxins
- These toxins damage cells making us ill
7
Q
How do viruses work and how do they damage the human body
A
- They invade the host cell
- They then use the host cell to reproduce
- When the viruses leave the cell, they can make it burst and it will die
8
Q
3 ways pathogens are spread
A
- Aerosol
- Water
- Direct contact
9
Q
How to reduce the spread of pathogens
A
- Washing hands
- Clean drinking water
- Condom during sex
- Isolate patients
- Vaccination
10
Q
What are antitoxins and their role
A
- Produced by lymphocytes
- Stick to toxin molecules neutralising them and prevent them from damaging cells
11
Q
Plant physical defence responses
A
- Tough cellulose cell walls
- Waxy cuticle which is slippery
- Bark (dead cells) which falls off
12
Q
Plant chemical defence responses
A
- Releasing antibacterial chemicals
- Release poisons to prevent against herbivores
13
Q
Plant mechanical defence responses
A
- Sharp thorns and hairs - irritate herbivores
- Mimicry
- Leaves which droop or curl - scare animals
14
Q
formula to find the bacteria at the end of the growth phase
A
number at end = number at start x 2^no. of divisions
