(4.1) Communicable diseases Flashcards
What is a pathogen?
A microorganism that causes disease
What are the 4 examples of pathogens?
- Bacteria
- Virus
- Fungi
- Protists
How are bacteria harmful?
Produces toxins and reproduces through binary fission
How does Cholera cause harm?
It’s toxins interfere with chloride ions
If the environment is optimum, how fast do bacteria reproduce?
Up to every 20 minutes
What type of bacteria is tuberculosis?
Mycobacterium
What is a mycobacterium?
A very small bacteria
What are 3 examples of diseases caused by bacteria?
- Tuberculosis
- Meningitis
- Ringrot
How do viruses cause harm?
Takes over cells and reproduces inside of them
How does HIV cause harm?
Targets the nucleus of a cell
What are the 2 examples of viruses?
- HIV
- Tobacco Mosaic Virus
How do fungi spread?
Hyphae release extracellular enzymes and digest surfaces e.g. skin
What is a hyphae?
In fungi and are branching filaments
What do many hyphae make?
A mycelium
What are the 3 examples of fungi?
- Athlete’s foot
- Black Sigatoka (banana plants)
- Ringworm
What are protists?
Complicated, single cell organisms
How do protists cause harm?
They enter the cell and feed on its contents
What are the 3 examples of protists?
- Malaria
- Potato/Tomato blight
- Sleeping sickness
What are the different forms of transmission?
- Direct contact
- Exchange of fluids
- Contamination
- Airborne
- Vector
What examples of disease are spread by direct contact?
- Meningitis
- Ringworm
- Athletes foot
What is exchange of fluids?
- Sex
- Blood transfusions
- Needles
What examples of disease are spread by exchange in fluid?
HIV
How does contamination cause disease?
faecal-oral - faeces gets into the body orally e.g. unwashed food
What are the 2 different types of airborne transmission?
- Truly
- Droplet
What examples of disease are spread by truly airborne transmission?
- Measles
- Anthrax
What examples of disease are spread by Vectors?
Maleria
What is the R value?
The rate of transmission - amount of people you’re likely to infect if you have an illness
What is the R0 value?
The natural/initial spread of disease without immunity
What are the physical/passive plant defences?
- cellulose
- waxy cuticles
- bark
- stomata closing
- callose
- tyrose
What is the role of callose?
A protein that blocks the phloem, specifically the sieve plates
What is the role of tylose?
Blocks the xylem
When are tylose and callose deposited?
When pathogens are detected
How do pathogens normally spread through plants?
Through the vascular tissues
What are the chemical defences of a plant?
- terpenoids
- phenols
- alkaloids
- defensins
- hydrolytic enzymes
What are examples of terpenoids?
Menthols and piney scents
What are the primary defences of the human body?
- The skin
- Mucous membrane
- Ear wax
- Tears
- Stomach acid
How are tears a primary defence?
They contain lysozyme
Describe how skin is a primary defence
- contains keratin which makes it impermeable
- when cut can clot due to an enzyme cascade
What is keratin produced by?
Keritanocytes
Describe the enzyme cascade
Collagen is exposed causing an enzyme cascade which turns fibrinogen into fibrin
What does -ogen at the end of a molecule mean?
It represents the inactive form of a molecule
What is underneath the mucous membrane and why?
- A good supply - surveillance for the specific immune response
- Patrolling macrophages
Where are mucous membranes?
On exchange surfaces e.g. lungs and digestive system
How is mucous produced?
By goblet cells
What can the mucous membrane trigger?
Coughing and sneezing
What is the role of the ciliated epithelial cells?
Waft pathogens up of the lungs that have been entrapped in mucous and then push it down into the stomach where it is destroyed by the stomach acid
How often do ciliated epithelial cells waft?
11-12 times a second
What is inflammation?
The direction of blood to infected and damaged areas. This causes vasodilation and moves neutrophils into the tissues.
What does inflammation cause?
Secondary responses
What are the 2 types of phagocytes?
- Neutrophils
- Macrophages
What does a neutrophil look like?
Has a multilobed nucleus
What does a red blood cell look like?
It is biconcave
What does a lymphocyte look like?
It has a large nucleus that nearly completely fills the cell
Describe the process of Phagocytosis
- The pathogen binds to either antibodies of through PAMP
- The neutrophil engulfs the pathogen
- Lysosomes fuse with the pathogen and create a phagolysosome
- The Lysosomes digest the pathogen into amino acids and proteins, all good nutrients is absorbed by the cell
