4.1 Communicable diseases and immunity Flashcards
What happens when a pathogen enters your body?
Mast cells are activated
What is released when mast cells are activated?
Histamines
Cytokines
What do Histamines do the body?
Dilate blood vessels
Make blood vessels more leaky
What happens to the body when the blood vessels are dilated and what does it cause?
Heat and redness causing pathogen production to slow down
What happens to the body when the blood vessels become ‘more leaky’?
More tissue fluid is made and there are more chemicals to the area meaning more white blood cells. The physical effects are pain and swelling
What do cytokines do to the body?
attract phagocytes
What are the two types of phagocytes?
Neutrophils
Macrophages
What are the differences between macrophages and neutrophils?
Nucleus - Macrophages round, Neutrophils lobed
How are cells tagged for phagocytosis?
Opsonins (antibodies)
What kind of phagocytes engulf pathogens?
Macrophages
What happens to a pathogen once it is engulfed?
It is packaged into a vesicle
What is the name of a vesicle containing a pathogen?
Phagosome
What happens to the phagosome inside the cell?
Is merged with the lysosome so it it can be digested with the strong digestive enzymes. All of the pathogen is digested apart from the antigens
What happens to the undigested antigens in phagocytosis?
They are put on the outside of the cell
How are T helper cells activated?
They have a CD4 receptor that recognises the undigested antigens on the macrophage and is then activated
What do T helper cells release?
Interleukins
What do interleukins do?
Signal other cells
What happens when T helper cells are activated?
Start mitosis
When they are replicating what do T helper cells replicate into?
T killer
T resistant
T memory
What is the job of T killer cells and how do they carry it out?
They kill pathogens by releasing perforin and H2O2
What does perforin do?
Kills cell by puncturing holes in the cell membrane to damage integrity and allow the insides of the cell to ooze out
What do T resistant cells do?
suppress the immune system to prevent autoimmunity
What is autoimmunity?
When the cells begin to attack each other even though they are part of the same body
What are T memory cells?
Allow immunological memory
How are B cells activated?
Interleukins
What is clonal selection?
An antigen presenting cell matches with the antibody on a B cell and then they are know as the B antigen presenting cell
What is clonal expansion?
The B cell with the correct antibody divides to fight the pathogen
What is the purpose of B memory cells?
Immunological memory
What are B plasma cells?
Allow the quicker replication of B cells with the correct antibody
What are antibodies also known as?
Immunogoblins
How many antigens can on antibody join to?
2
What are the two kinds of chain?
heavy and light
How are the chains held together?
Disulfides bridges
What are the two regions in an antibody?
Constant and Variable
Where is the heavy chain?
On the inside
Where is the light chain?
On the outside
How many antigens can an antibody join to?
2
What are the different ways an antibody can act?
Agglutins
Oppsonins
Antitoxins
What is the function of an Agglutin?
Glue together pathogens to make them more accessible and noticeable for pahgocytosis
What is the function of an oppsonin?
Tag pathogens
What is the function of antitoxins?
To neutralise any toxins that may be released
How do T resistant cells end the process of the auto immune system?
They kill all other white blood cells except for memory cells to stop them from attacking each other when they have killed all pathogens
What are organisms that cause disease called?
Pathogens
What is the organism in which a pathogen lives called?
A host
How do pathogens live/survive?
By taking nutrition from the host
What are the different organisms that can cause disease?
Bacteria
Viruses
Fungi
Protoctista
What kingdom do bacteria belong to?
Prokaryotae
How do bacteria damage a host?
When they have entered the host they multiply rapidly and they damage cells by releasing waste products and toxins
What do fungi cause disease in?
A variety in plant and animals
How do fungi work?
They live on the skin of animal and its hyphae form a mycelium which grows under the skin’s surface. The fungus can send out specialised reproductive hyphae which grow to the surface of the skin to release spores causing redness and irritation
Where does fungus often live in plants?
Vascular tissue
How do viruses work?
They invade cells and take over the genetic machinery and organelles of the cell. This causes the cell to manufacture more copies of the virus causing the host cell to eventually burst releasing more viruses to infect healthy cells
How are protoctista causes?
By protoctists
What are protoctists?
Animal hosts that spread from one person to another e.g. mosquitos
What is an example of a diseases caused by bacteria?
Tuberculosis
What is an example of a diseases caused by a Virus?
HIV/AIDS
What is an example of a diseases caused by fungus?
Athlete’s foot
What is an example of a diseases caused by protoctista?
Malaria
What are the different types of direct transmission (between animals)?
Physical contact (touching)
Faecal-Oral transmission
Droplet infection
Spores
What are factors that affect transmission?
Hygiene (regularly washing hands)
Treatment of water (using sewage to fertilise crops is common in many parts of the world)
Catch it - Bin it - Kill it
Use of a mask
What are social factors that affect transmission?
Overcrowding
Poor ventilation
Poor health
Poor diet
Homelessness
Being around people who have migrated from places where the disease is common
What is indirect transmission?
A vector
How can plant pathogens be spread?
Through soil - entering the roots
In the wind - fungi pores
Insects - acts as a vector
What are ideal conditions for most diseases?
Warm and moist
What can damage and kill pathogens?
Cold winter weather
