17) Immunity Flashcards
(22 cards)
Pathogen
Microorganism that live in a host and cause disease
e.g. virus, bacteria fungi
Infection disease
Caused by pathogen and can be transmitted from one living organism to another
Non infectious disease
Not caused by pathogen and cant be transmitted from one organism to another e.g. CHD,anemia
Way of spread of disease
A)Indirect
1.By contaminated food and water
2.By vector
3.In droplets through sneezing or coughing
B)Direct
1. By touch
2. From pregnant woman to her fetus through placenta/breast feeding
3.Mixing of body fluid or blood transfusion
4 ways to control of spread of disease
1.Personal hygiene : brush teeth, wash hands.
2.Food hygiene: Cook food thoroughly, cover food, store food in fridge/ freezer
3.Safe landfill
4.Defense mechanisms
First line of defence barriers
- Mechanical barrier:
-Skin
-Hair in nose
-scabs
2.Chemical barrier:
-Tears, containing lysozyme which destroy bacterial cell wall killing it
-Mucus contains enzymes to kill bacteria
-Acid in stomach kill bacteria by denaturing their enzymes
-Saliva, contains enzymes to digest and kill bacteria
Second line of defence (immune response)
1.Lymphocytes will detect the non self antigen of pathogen
2.Lymphocytes will start to divide by mitosis forming genetically identical lymphocytes
3.Lymphocytes releases antibodies to kill pathogen
4.Leaving memory cells for faster secondary immune response
-Where memory cells will divide faster and produce more antibodies at a faster rate, so kill pathogen without falling ill
How antibodies work
1.Antibodies have a specific binding site
2.Complementary to specific antigen
3.So they bind together to form antibody antigen complex
4. To destroy the pathogen in a direct or indirect way
A) Stick to the pathogen to mark for phagocytes to engulf and digest by digestive enzyme
B) Destroy cell wall causing bacteria to lyse
C)Neutralise toxins
D) clump them together
Active immune response types
1.Primary immune response
2.Secondary immune response
Primary immune response
-Slower
1.Involves no memory cells
2.Only specific lymphocytes, specific to the antigen
3. Where it takes time for the body’s own lymphocytes to
-Detect the antigen of pathogen
-Divide by mitosis
-Release antibodies
-Kill pathogen
Secondary immune response
-Faster
1. Involves memory cells
2. So memory cells will divide faster
3. And release more antibodies
4. At a faster rate
Vaccine
1.Inject a weak or dead pathogen
2.Stimulate an active immune response
3.Stimulates a primary immune response
4.Where body’s own lymphocytes detect the antigen
5.Divide by mitosis and form a clone of lymphocytes
6.Release antibodies to kill pathogen
7.Leaving memory cells for faster secondary immune response
Explain the importance of vaccination/
Explain the role of vaccine in controlling spread of disease
1.Inject a weak or dead pathogen
2.Stimulate an active immune response
3.Stimulates a primary immune response
4.Where body’s own lymphocytes detect the antigen
5.Divide by mitosis and form a clone of lymphocytes
6.Release antibodies to kill pathogen
7.Leaving memory cells for faster secondary immune response
-To provide herd immunity
-So less people in which pathogen can replicate
-So reducing spread of disease
-Reducing pool of infected people
Compare active immunity to passive immunity
Active immunity:
-Shows immune response
- Lymphocytes release antibodies
-involves memory cells
-providing long term immunity
E.g. Natural by experiencing the disease, artificial by vaccine
Passive immunity:
-No immune response
-Receives ready made antibodies (lymphocytes doesn’t release antibodies)
-No memory cells
-Short term immunity
E.g. Natural passive immunity by mother to fetus through placenta/breast feeding, Artificial by injecting ready made antibodies
Advantages and disadvantages of active immunity
Advantage: Memory cells present, providing long term immunity
Disadvantage: Takes a long time, for lymphocytes to detect, divide and release antibodies to leave memory cells
Advantages and disadvantages of passive immunity
Advantage: Provides immediate protection against pathogen
Disadvantages: No memory cells, so short term immunity
How to boost immune system
- Good balanced diet
- Good hygiene
- Stop smoking and drinking alcohol
- Regular exercise
Why are some vaccines taken on two doses
- Vaccine is less likely to cause unwanted side effects
- Second dose will stimulate secondary immune response that will give extra protection by more production of memory cells and antibodies
Example of auto immune disease
Diabetes type 1
-where lymphocytes attack beta cells in pancreas
-which are responsible for secreting insulin
-No insulin, blood glucose will increase
Symptoms: Thirst, sweat, frequent urination, pale skin, blurry vision and weight loss.
Structures of bacteria that is not found if eukaryotes
1.Plasmids
2.Smaller ribosomes
3.Cell wall made of murein
4. Loop of DNA
Common structures between bacteria and eukaryotes
- Cell membrane
- Cytoplasm
- Ribosome
- DNA
Structures in eukaryotes that are not found in bacteria
- Nucleus
- Mitochondria
- endoplasmic reticulum
