Communicable diseases Flashcards
1
Q
Define features of: Bacteria
A
- No membrane bound nucleus
- Multiply in the tissues
- Produce toxins
- Gram positive or negative
- Produce rapidly, prokaryotes.
2
Q
Define features of: Fungi
A
- Microscopic
- Eukaryotic
- Grouped into yeasts/ molds
- Inflammation, thrush
- Digestion is extracellular
- Saptophytic= type of parasite that feeds on dead tissue.
- Pathogenic= feeds on living tissue
3
Q
Define features of: Vrisues
A
- Not true living- multiplies in host cells, operates host cell’s machinery
- Protein coat
- 0.02-0.3 micrometers
- Can evolve and develop adaptations to host
- Modified to treat disease by killing the pathogen.
4
Q
Define features of: Protists
A
- Includes algae and slime molds
- Eukaryotic, tends to be single celled
- Few are pathogenic
- Needs vector to transfer.
5
Q
Name and describe symptoms and treatments for bacterial diseases.
A
- Tuberculosis
- Persistent cough, weight loss, fever
- often affects lungs
- Treated with antibiotics - Bacterial meningitis
- Inflammation of membranes around the brain and spinal cord, blood poisoning, death, rash.
- Vaccines, antibiotics. - Ring rot (potatoes)
- Ring of decay in vascular tissue
- No cure, cannot grow potatoes in same field for 2 years.
6
Q
Name and describe symptoms and treatments for viral diseases.
A
- HIV
- Flu-like symptoms
- No cure, don’t share needles/ exchange bodily fluids, antiretrovial drugs to control onset. - Influenza
- Cough, blocked nose, fever, headache, secondary conitions.
- Manage symptoms - TMV (plants)
- Mottling, discoloration of leaves, growth stunt
- No cure
7
Q
Name and describe symptoms and treatments for fungal diseases.
A
- Black sigatoka (bananas)
- Leaf spots on bananas (black)
- Fungicides - Ringworm
- Grey, white, crusty infectious circular areas
- Antifungal creams, medicines. - Athlete’s foot
- Form of human ringworm, cracking, scaling
- Antifungal creams
8
Q
Name and describe symptoms and treatments for protist diseases.
A
- Blight
- Spreads through hyphae
- Destroys leafs, tubers, fruit
- Chemical treatments - Malaria
- Headache, fever, coma, death
- Control vector, vaccinations
9
Q
Name the 6 ways pathogens affecting animals are transmitted
A
- Direct contact
- Innoculation (break in the skin)
- Ingestion
- Fromites (inanimate objects)
- Droplet infection
- Vectors.
10
Q
What are factors affecting transmission? (animals)
A
- Overcrowding
- Poor nutrition
- Compromised immune system
- Socioeconomic lack (education, healthcare workers)
- Poor waste disposal (breeding sites)
- Climate change
- Culture and infrastructure
11
Q
Name modes of transmission in plants
A
Direct contact
Indirect contact (spores, pathogens in soil)
12
Q
Name some factors affecting the transmission of pathogens in plants
A
- Planting varieties of disease-susceptible crops
- Overcrowding
- Poor mineral nutrition
- Damp, warm conditions (increase survival and spread)
- Climate change (increased rain and wind acts as vector)
13
Q
What does callose do?
A
- Deposited in the sieve tubes at the end of growing season
- blocks flow and prevents spread
- impedes cellular penetration
14
Q
What does lignin do?
A
- Thickens cell walls
- Waterproof and is nearly indigestible
15
Q
What are two physical barriers of plants?
A
- Bark= releases chemicals
- Waxy cuticles= prevents water accumulation which pathogens feed on
- Stomatal closure
- Cellulose cell wall= contains chemicals that can be activated.
16
Q
Name some of the functions of Tylose.
A
- A balloon like swelling that fills the xylem.
- When fully formed it blocks the vessel, preventing water flow and spread.
- Contains a high concentration of chemicals toxic to pathogens
17
Q
Describe how the plant response to a pathogen is triggered. (5)
A
- Some molecules from the pathogen are recognised directly by the plant cell.
- When pathogenic enzymes break down the cell wall the products are recognised.
- Sigalling molecules are realeased and alert the nucleus to attack.
- Callose and lignin made to strengthen cell wall
- Defensive chemicals give the alarm to other cells before they are attacked
18
Q
How does the skin act as a barrier?
A
- It acts as a physical barrier
- Contains sebum which lowers pH to create a hostile environment so pathogens cannot survive to reproduce and spread
- Epidermis cells dry out as they migrate to the surface of the skin
19
Q
What do lysozymes do?
A
- Found in tears
- enzyme
- protect eyes
20
Q
What are some examples of expulsive reflexes?
A
- Response to irritation that may be caused by the presence of microorganisms or the toxins they release
- coughing
- sneezing
- vomitting
21
Q
What do mucous membranes do?
A
- Line internal cavities exposed to external air
- Goblet cells produce mucus, ciliated epithelial cells waft mucus up so it can be swallowed where the pathogen is killed by stomach acid
22
Q
What are the roles of; stomach acid, ear wax and the female reproductive system
A
Stomach acid digests pathogens
Ear wax is sticky and traps pathogens
Female reproductive system has a mucus plug in the cervix, vagina has acidic conditions (pathogens cannot survive)
23
Q
Describe the blood clot cascade
A
- Damaged tissue
- Platelets activated
- Forms a temporary plug, release clotting factors such as thromboplastin
- Thromboplastin together with calcium ions in the blood act on a blood protein called prothrombin
- this converts the prothrombin into an active enzyme called thrombin
- Thrombin acts on a soluble blood protein called fibrinogen catalysing the formation of insoluble fibrin
- Fibrin forms a mesh which traps red blood cells forming a blood clot/ thrombus
24
Q
What is a chemical that platelets also release?
A
Platelets release serotonin= causes SM cells in blood vessels to contract, narrowing the blood vessel to reduce flow to the damaged area
25
Describe how a scab is formed
- the clot dries out, forming a tough hard scab which keeps out pathogens
- new epidermal cells grow underneath
- Blood vessels regenerate, collagen fibres are deposited to strengthen new tissue
- Scab sloughs off when new epidermis is thick enough
26
What is inflammation?
- A localised response to pathogens or damage resulting in inflammation at the site of the wound. Damaged mast cells release histamines and cytokines
27
What do histamines do?
- Cause vasodilation which causes heat and redness
- Make vessel walls more permeable so plasma is forced out to form tissue fluid which causes swelling and pain
- Raised temperature prevents pathogens from reproducing
28
What do cytokines do?
- Attract phagocytes
- leads to phagocytosis
- released by phagocytes that engulfed a pathogen
- cell signalling molecule informing other phagocytes that the body is under attack
29
What is the humoral response?
Activation of B cells into plasma cells that produce and secrete antibodies to a specific antigen
30
What is the cell mediated response?
Immune response without antibodies, involves activation of macrophages. Antigen specific T-lymphocytes and the release of various cytokines in the response to an antigen
31
What is an autoimmune disease?
When the immune system attacks a part of the body, usually arises when antibodies start to attack our own antigens
32
What is the point in variable regions?
They are complementary to one specific antigen
33
What happens during opsonisation?
- The antibody acts as a binding site for phagocytic cells
- May attach to binding site of pathogen to the host cell (neutralisation)
- Macrophage has a receptor site complementary to constant region of the antibody
34
What happens during agglutination?
- Causes pathogens carrying AG/AB complex to clump together
- prevents spread through body so pathogen can't enter host
- Easier for phagocytes to engulf more pathogens at a time
35
What do anti-toxins do?
- Antibodies can bind to the toxin produced by pathogens to make them less harmful
36
How do antibodies respond to the proteins on the surface of a virus?
- Proteins recognise and bind to receptors on host cell, this is how a virus enters a host
- Antibodies bind to viruses and stop them attaching to host cells
37
Describe natural active immunity
Infection by a pathogen causes production of antibodies and B memory cells
38
Describe natural passive immunity
Antibodies passed on to baby in mother's colostrum
39
What is Artificial active immunity?
Vaccinations
40
What is artificial passive immunity?
Antibodies are extracted from one host and are inserted into another.
41
How do vaccines result in immunity?
- Vaccines contain antigens that cause the body to manufacture antibodies and memory cells complementary to a pathogen
- If infected again the memory cells are triggered to activate the immune response quickly to destroy the pathogen
42
What are different types of vaccines (4)
1. Whole live microorganisms of a less harmful form
2. Attenuated (weakened)
3. Dead pathogen
4. Harmless toxin produced by a pathogen
43
Why might an individual not respond well to vaccines?
1. Immunosupressant drugs
2. Weak immune system (elderly)
3. Immunocompromised
4. Newborns
44
What is the purpose of booster vaccines?
Memory cells produce antibodies quickly for longer lasting protection
Ensures memory cells are still being produced
45
How does antibiotic resistance arise?
1. Bacteria including a resistant variety get bathed
2. Normal bacteria die
3. Leaves resistant bacteria to reproduce enough to evolve into a resistant strain
46
Describe MRSA
1. Carried by up to 30% of pop
2. Can cause boils or abscesses, fatal septicaemia
3. treated with methicilin, similar to penicillin
4. Can get MRSA from being long term in a health care facility
47
Describe C dificile
1. Bacterium in 5% of population's guts
2. Produces toxins which damage the intestines, leading to diarrhoea, possibly even death
3. Antibiotics kill off 'helpful' bacteria, allowing C.D to reproduce
4. Part of normal gut microflora
5. Arises through being treated with antibiotics for a long amount of time
48
What are some active defenses included in a plant response to pathogens?
1. Cell walls become thickened
2. Deposition of callose which impedes cellular penetration
3. Oxidative bursts produce reactive oxygen which is capable of damaging invading cells
4. Increases production of chemicals
49
What does necrosis mean?
- Deliberate cell suicide, a few cells are sacrificed to save the plant
- By killing cells around infection the pathogen's access to water is limited
50
Define the term 'canker'
- Sunken necrotic region in the woody tissue of a tree
- Causes death of cambium tissue
51
How do antibodies defend the body?
1. The antibody of the antigen antibody complex acts as an opsonin, complex is easily engulfed and digested
2. Most pathogens can no longer invade host cells once they are a part of an antigen antibody complex
3. Act as agglutinins causing pathogens carrying the complex to clump together
52
What do plasma cells do?
Produce antibodies to a particular antigen and release them into circulation
53
What do B effector cells do?
Divide to form plasma cell clones
54
What do T killer cells do?
Produce a chemical called perforin which kills the pathogen by making holes in the membrane
55
What do T memory cells do?
They live for a long time and are part of the immunological memory
56
What do T regulator cells do?
Suppress the immune system, acting to control and regulate it, make sure the body recognises self antigens and does not set up an autoimmune response.
57
Describe cell mediated immunity (3)
My Toe Twisted
1. Macrophages engulf and digest pathogens in phagocytosis and process the antigens from the surface of the pathogen to produce APC
2. T helper cells become activated and release interleukins which stimulate T cells to divide rapidly by mitosis. They also induce phagocytosis
3. This forms clones of identical Th cells that carry the right antigen to bind to a pathogen
58
Describe humoral immunity (5)
A Illuminated Angel Plays Soccer
1. Activated Th cells bind to the B cell APC (clonal selection)- the point at which the B cell with antibody complementary to antigen are selected for cloning
2. Interleukins activate the B cells
3. Activated B cells divide by mitosis to give clones of plasma cells and B memory cells. This is clonal expansion
4. Plasma cells produce antibodies that fit antigens on pathogen. They act as opsonins or agglutinins
5. Some B cells develop into B memory cells
59
What happens if the body is infected again?
B memory cells divide to form plasma cell clones before symptoms start/ before pathogens divide.
60
What do agglutinins do?
Cause pathogens with the antigen-antibody complex to clump together for macrophages to engulf and digest more at a time
61
What are opsonins?
Chemicals that bind to and tag foreign cells, making them easily recognisable to phagocytes
62
What do interleukins do?
Activate the B cells which causes them to divide by mitosis
Induces phagocytosis
63
What does the constant region do?
The antibody uses this to bind to phagocytes
64
What does the variable region do?
Has a unique structure that is different for each antibody molecule. It is the antigen binding site where the antibody can recognise and bind to a particular antigen
65
What is a hinge region and what does it do?
Flexible, allow the branches of the Y to move away from each other so the antibody can bind to multiple antigens
