B6.3 Flashcards
What is health
A complete state of physical emotional and social wellbeing, and not merley the abscence of disease or infermity
What is disease
The deviation from the normal structure and function of an organism
What is a communicable disease
A disease caused by pathogens that can be transmitted between organisms
What are pathogens
Microorganisms that can cause disease
They most commonly damage cells or release toxins
What are the 4 most common pathogens
Fungi
Bacteria
Viruses
Protozoa
What are antigens
Proteins on the surface of cells and microorganisms
What is a non communicable disease
A disease that cannot be spread between microorganisms such as obesity or cystic fibrosis
What is HIV
Human immunodeficiency virus which causes aids
It attacks T-lymphocytes (by binding to the cells and replicating)
What diseases do AIDS patients catch
People with acquired immune deficiency syndrome have a weakened immune system
This means they can catch diseases such as Tuberculosis from tuberculosis causing bacteria
What does M Tuberculosis do / how does it effect the body
Infection destroys alveolar tissue in the lungs
Causes less oxygen to diffuse into the lungs (due to lower surface area)
Less ATP could be made, so the organism would respire faster
As there is less oxygen in the blood the organism will have breathing problems
How is HIV treated
Using antiviral medicines, to stop the virus replicating
How is HIV spread
Through bodily fluids
Sharing needles
How can HIV spread be reduced
Wear protection such as condoms when having sex
Never sharing needles
Prep is a drug taken prior to exposure, to reduce risk of infection
Pep is taken within 72 hours after exposure to reduce infection
How is staph infection caused
Caused by staph bacteria (staphylococcus)
Symptoms of staph infection
Skin infection
Red lumps on skin (boils)
Red and swollen skin
Sores and blisters
How is staph infection transferred
It can be transferred by contact, but is only dangerous if it enters the body
How can staph be treated
Taking antibiotics such as oxacillin
How is the spread of spah infection reduced
Keeping personal items personal, and constantly cleaning surfaces
What diseases can staph infection cause
If it enters the blood stream it can cause sepsis
What is ringworm
A fungal infection seen on your skin
Causes a scaly / dr / swollen rash
Often appears in silver / red ring shape
How is ringworm treated
Using antifungal creams onto the site
How is the spread of ringworm prevented
Direct and indirect contact
(Sharing items /clothing)
Shower and change clothing once per day
Complications of ringworm
Hair loss
Scarring
Nail deformities
What is influenza
(commonly called the flu)
A common virus that can be spread between people through dropplets
Influenza symptoms
High temperature, headache, bad cold, aching body
How to treat influenza
Annual flu vaccine
Painkillers help to reduce the effects
(People often recover after a week)
Complications of influenza
Can lead to infections such as pneumonia or ear infections
How is the spread of influenza reduced
Covering your mouth and nose when you sneeze / cough
Regularly wash hands
What are the main ways disease is transmitted in animals
.Airborne → droplets and spores
.Direct contact → skin to skin / bodily fluids
.Indirect contact / vehicular contact → surfaces food bedding towels
How do female mosquitos pass on malaria
Only female mosquitos bite humans for blood
In doing this they pass on their saliva which contains anticoagulant properties (so it can take the blood)
In the saliva malaria can also be found
Malaria can be transferred through protists-plasmodium
What is the lytic cycle
A cycle where viruses replicate themselves, destroying a cell
Viruses have receptors so they can bind to specific cells
The virus recognises the pattern of receptors (proteins) on the cell it should infect (these are complimentary to its antigens)
Attaching to the cell allows the virus to insert intergrase into the cell (allowing it to inject its DNA or RNA)
The virus forces the cell to replicate its dna
(The virus DNA is transcribed to RNA so that the cell will transcribe it
A virus is then assembled
The new virus then takes a part of the cell membrane for protection (when leaving the cell)
This causes the cell to be damaged or destroyed
What is a retro virus
A virus with RNA as its genetic material
It uses enzymes to convert RNA to DNA
It the inserts its DNA into the hosts genome to be transcribed
It uses reverse transcriptase
What is reverse transcription
Process of changing RNA to DNA
What is an Incubation period (infection)
Time between being infected and the symptoms being displayed
What is Epidemology
The study of incidence and distributiin if disease
How is disease monitored
Testing for new cases
Death rates
R (reproduction) number
What is an R number
How many cases would each new case cause
How do you test for disease
Looking for symptoms → visual identification
Testing for antigens
PCR test (polymerase chain reaction) → detects genetic material of an organism
How does the skin protect from disease
Its a physical barrier preventing microorganisms from entering the blood
Microbiomes of healthy bacteria compete with pathogens (reduces the number of pathogens)
Glands below your skin secrete sebum which has a low pH (denatures enzymes on the pathogens)
What cells release mucus
Goblet cells
How does mucus and cilia combat against disease
Mucus traps dust and microorganisms preventing them entering your lungs
Cilia (small hairs) move the mucus containing pathogens away from the lungs
The mucus is either swallowed or coughed out
Why is swallowing mucus better than coughing it out
Digestive acid in your stomach has a low pH
This would cause enzymes in pathogens to denature
This would prevent growth
This would also cause certain enzymes controlled reactions like cellular respiration and DNA replication to not function
What are lysozymes
Enzymes that break down peptidoglycan in bacteria cell walls
It can be found in tears and mucus
Why does breaking down peptidoglycan in cell walls kill the cell
It causes the cell to become weaker and more prone to lysis
How do nasal hairs and eyelashes defend against pathogens
Prevents entry of pathogens into the body
What do blood clots do
They provide a barrier preventing pathogens from entering the blood.
How do blood clots / scabs form
When the skin is cut blood begins to leak out
This causes the platelets to become activated (sticky)
Soluble fibrinogen is converted into insoluble fibrin (a protein) by thrombin (an enzyme)
This traps red blood cells forming a clot
The clot eventually hardens forming a scab
What is an anticoagulent
Something that prevents the blood from coming
How do anticoagulant drugs prevent the blood
They bind to the active side of the enzyme (thrombin) that converts fibrinogen to fibrin, as there are no active sides for fibrinogen to bind to
As there is no fibrin a blood clot cannot form
What is a phagocyte
A tyoe of white blood cell that carry out phagocytosis
What happens during phagocytosis
Phagocytes engulf microorganisms and enzymes break down microorganisms
What enzymes can be found in phagocytes
Protease → break down proteins
Carbohydrase → break down carbohydrates
Lypase → break down lipids
Lysozymes → breaks down peptidoglycan
Nuclease → breaks down DNA and RNA
How do bacteria damage cells
Kill cells
Release toxins
What are T-Lymphocytes
White blood cells that:
Recruit phagocytes
Release digestive enzymes to break down microorganisms
What are B-Lymphocytes
White blood cells
Produce antibodies which can bind to specific shaped antigens
What are antibidies
Proteins which can bind to 2 specifically shaped antigens at one time
How does your immune system react to a primary (first) infection
Slow immune response (first encountering the pathogen)
Takes time for antigens to be produced
Released memory B-Lymphocytes which will recognise the antigen
How does your immune system react to a secondary infection
Second time coming in contact with the pathogen
Faster immune response as memory B-Lymphocytes can release antigens faster
How do primary and secondary infection responses differ
In a secondary response more antigens can be released at a greater speed (in less time)
What is Agglutination
Antibodies clump pathogens together
Phagocytes then engulf and digest the pathogens
(Also mark the pathogen so phagocytes know to digest them)
What do vaccines do
Vaccines create artificial immunity by introducing dead or weakened pathogens into the body
This means memory B-Lymphocytes can be made, making the first natural response to be as fast as a natural secondary response
Main side effect of a vaccine
May make you feel fatigued as your immune system has to fight against the pathogen
How do MRNA vaccines work
mRNA that codes for specific antigens (of a virus / bacteria) is injected
Cells take up the mRNA and translate it
T-Lymphocytes recognise the antigen and break it down
Memory B-Lymphocytes will be produced leading to a quicker, second immune response
What is herd immunity
If 75% to 85% of a group is vaccinated (immune) the pathogen is unlikely to spread
What are antivirals
Drugs that destroy viruses by preventing them from replicating.
They are specifically designed to act on one type of virus.
E.g
They could:
Block virus from entering a host cell
Prevent virus from releasing genetic material
Prevent the virus from inserting its data into the host cells DNA
What are antispetics
Something that kills / neutralises all pathogens while not damaging human tissue
What are antibiotics
A drug that kills bacteria
They have no effects on viruses or fungi
What is Aseptic Technique
A technique used to ensure that no foreign microorganisms are introduced into a sample being tested
What does aseptic mean
Without microorganisms
What is a sterile environment
An environment free of microorganisms
How is aseptic technique performed
First a sterile environment must be formed
Bunsen burner is used to create an updraft preventing any microorganisms from being in the area.
70% ethanol is used to clean surfaces / autoclave glassware
Wash hands
Heat inoculation loop in the flame
Microorganisms can then be applied via streak or spread plating
The bacteria is then sealed with a + pattern of tape ensuring oxygen can enter but no bacteria can escape
Why when testing bacteria does the petri dish need oxygen inside of it
In order to prevent harmful anaerobic bacteria from forming
How is streak plating performed
After sterilising the loop dip it into a sample of bacteria
Make four or five streaks against one edge of an agar plate
Flame and cool the loop
Make a new set of streaks by crossing over the original set, spreading them out
Repeat these two steps twice
Fix the lid shut with a + of tape and label the plate
Lie the plate upside down as it incubates
Why are plates with bacterial growth laid upside down during incubation
To prevent any contamination from entering the dish
What are bactericidal antibiotics
Antibiotics which kill bacteria
What are bacteriostatic antibiotics
Antibiotics which inhibit growth
Give an example of antispetics
Iodine and alcohols
Why dont antibiotics work on viruses
As the viruses have different enzymes
Why dont antibiotics affect humans
As they target the cell wall, and animals dont have cell walls
What happens in pre clinical trials
A drug is tested on animals or tissue / cell culture
What is observed during pre clinical trials
Success of a drug (efficacy)
Dosage sizes
Toxicity
Side effects
When do clinical trials begin
If pre clinical trials show a successful drug it may move to clinical trials
What are the 3 phases in clinical trials
1) Tested on a small group of around 100
Mainly looking at side effects and dosage size
2) Testing on more patients with the disease (200 - 300 patients)
Looking at dosage, side effects and if the drug is effective
3) A double blind randomised controlled trial
Testing on patients (300 - 1000)
Looks at if the drug is effective, and any side effects
What is a double blind randomised controlled trial
A trial with two groups.
Each person is assigned to a group randomly
One group receives a placebo (control group)
One group receives the drug
Even the doctors do not know who is given what (double blind)
This is done to remove bias
What is the purpose of using a placebo
To highlight any psychological effects of taking a drug
What are monoclonal antibodies
An antibody produced by a single clone of cells
What is a hybridoma cell
Fused cells
What is HPV
Human Papilloma Virus
Cause cervical cancer+ genital warts
Spread by skin to skin contact
How are MABs used to combat cancer
They are tagged with a fluorescent tag that can be detected using ultra violet
These bind to antigens on cancer cells showing where the cells are
They also mark the cancer cells for T-cells (T-killer cells)
They can also be tagged with a drug to treat cancer
What is cirrhosis
Liver scarring caused by alcohol abuse (excessive consumption) over time
Prevents your liver from functioning
Alcohol is toxic so when broken down it releases chemicals which damage the liver
What is bronchitis
A nom communicable disease
Inflammation of the lungs
Excess mucus production blocks airways making it harder to breathe
This is because less oxygen reaches the alveoli, so less oxygen can be transported around the body (less aerobic respiration around the body)
How is bronchitis caused
Chemicals in cigarette smoke damage your lungs
This leads to inflammation.
Excess mucus is produced to trap microorganisms and dust so that your cillia can move it away from the airways
Substance in Smoking and damage they cause:
Tar - collects in the lungs → is carcinogenic
Nicotine - addictive drug that affects the nervous system. Makes the heart beat faster and narrows blood vessels
Carbon monoxide - binds to haemoglobin over oxygen (less oxygen for the body)
Particulates - small pieces of solid are engulfed by white blood cells. An enzyme is released that weakens the alvioli
What does alcohol do (as its a depressant)
It slows down the bodies reactions (e.g slower nervous system)
What is Type 2 Diabetes
A non communicable disease caused by lifestyle → too much sugar
Cause by an insulin resistance → sugar is not taken up when insulin binds to receptor cells
Blood glucose levels are always high
Also caused when not enough insulin is produced
What is CVD
Cardiovascular disease is a general term for a disease that effects the heart or blood vessels
What is atherosclerosis
The build up of fats and substances in the artery wall
Where does atherosclerosis occur
In the arteries
What causes atherosclerosis
High blood pressure, causes the endothelium to be damaged.
Cholesterol then builds up in the damaged area, narrowing the lumen of the arteries
(Build up of cholesterol is an atheroma)
What is cholesterol
A molecule which transport lipids
Why do atheromas harden
Due to the calcium in cholesterol
How do atheromas further increases blood pressure
Hardened atheromas reduce the elasticity of the elastic fibers and narrows the lumen
This prevents the artery from stretching and recoiling.
A rigid artery cannot stretch so blood pressure remains high
What is thrombosis
Blood clots forming in arteries and veins
What is a positive feedback loop
When the product of a reaction leads to an increase in that reaction
How does having a high salt diet increase blood pressure
It causes an increased solvent concentration in blood cells.
Water from around the blood cells diffuses into them via osmosis increasing the size of the cells (cells stretch)
(Pressure = force / area)
What is coronary heart disease
A non communicable disease caused by atheromas in coronary veins and arteries
What are coronary arteries
Arteries which supply oxygen to cardiac MUSCLE
What happens when atheromas form in coronary arteries
Blood flow is reduced
Less oxygen is brought to cardiac muscle
Less oxygen for aerobic respiration
Less ATP is produced
Cardiac muscle cannot contract (to push blood around the body)
Cardiac cells can die
What happens if cardiac muscle is fully deprived of oxygen
Cardiac muscle cells ide
This can cause a heart attack
Why does having a heart attack increase the risk of having a heart attack (positive feedback loop)
Having a heart attack means the heart is weaker (as cardiac muscle is damaged)
This means blood is pumped around the body with a lesser force
To maintain high pressure in the blood the heart contracts faster.
As the heart is contracting faster the risk of a heart attack is greater
How do stokes occur
Blood clots in the brain
Prevents neurons from having oxygen → cant function
What happens when blood pressure increases too much
The blood vessel will rupture
How does carbon monoxide impact your body (from smoking)
Carbon monoxide has a better affinity than oxygen and will bind to haemoglobin first
This reduces oxygen concentration in your blood, as less oxygen binds to haemoglobin
Your heart beats faster to try and receive more oxygen so your blood pressure increases
This causes atherosclerosis
How can you prevent CVD (lifestyle)
Exercise more
Eat healthier
Dont drink or smoke
What is hypertension
High blood pressure
What are statins + side effects
A drug that prevents the formation of blood cholesterol
Makes the liver remove more cholesterol from the blood
Upset stomach
What are antiplatelets + side effects
A drug that reduces heart attack risk by reducing the stickiness of blood platelets, causes less clotting
Internal bleeding
What are beta blockers + side effects
A drug that reduces high blood pressure by reducing the effects of adrenaline.
This slows your heartbeat and improves blood flow.
Dizziness / tiredness
What are nitrates (drug) + side effect
A drug that widens blood vessels by relaxing blood vessel walls.
Allows more blood to flow through at a low pressure
Headaches and dizziness
What are anticoagulants + risks
Drugs that reduce blood pressure by preventing the blood from clotting.
Prevents volume of arteries from decreaing (as blood clots will decrease the size of arteries)
Can lead to internal bleeding, you would lose more blood if you cut your skin
How are stents used to help prevent cvd
A wire mesh attached to a balloon is inserted into the area of a blood clot / atheroma
The wire is passed through your arteries from your groin or wrist
When at the correct area the balloon is inflated, expanding the wire mesh
This stretches the artery expanding its size, and the volume of blood it can hold.
The balloon can then be removed leaving the mesh
Why do you need to be on blood thinners after having a stent put in
To prevent blood clots from forming in the stent, preventing it from functioning
(Take thinners for a few months or year)
What is angioplatsy
Name of a procedure where the blood vessels are widened using stents
What is coronary heart bipass
A procedure where blood flow is redirected from an area of damage
A vein is taken from the leg (or other areas) and grafted onto an artery (often multiple coronary arteries).
The blood will flow through the new vein instead, reducing blood pressure
What are organ transplants
A medical procedure where an organi is removed from one body and placed into another.
Why do organs need to be a match
To reduce the risk of rejection, and therefore have a successful transplant
What is needed for organs to match
The same blood type
What are the main 4 types of blood
Group A - A antigens on the red blood cell, anti-B antibodies in the blood plasma
Group B - B antigen on the red blood cell, anti-A antibodies in the blood plasma
Group Ab - Type A and B antigens on the blood cell, no antibodies in the plasma
Group O - No antigens, anti- A and anti-B antibodies in the plasma
Why is type O blood the best to use
As they have no antigens on the cell and can therefore there is no risk of rejection due to antibodies
What are autologous stem cell transplants
Transplants of your own stem cells.
What are allogenic stem cell transplants
Donor stem cells are used
When are autologous stem cell transplants used
Radiation in chemotherapy can kill stem cells.
Before the procedure some of your stem cells are taken and frozen
After the procedure they are injected back into the patient
THERE IS NO RISK OF REJECTION
What are the main risks with both types of stem cell transplants
BOTH HAVE A RISK OF INFECTION
What are the issues with allogenic transplants
There is a risk of rejection as the antigens are foreign
What are induced pluripotent stem cells
Cells are taken from the patient and genes are altered to make that cell an embryonic pluripotent cell.
This removes risk of rejection (as the antigens are the same as the patients) and is better than using ASCs as they can divide and differentiate into any specialised cell type
