Biology - B2 Keeping healthy

Disease

Disease

a condition that commonly damages cells of the host and impairs regular function of the organism

Communicable disease

Disease that can pass to other organisms

Pathogen

A microorganism (such as fungi, protists, bacteria and viruses) that cause disease

Non - communicable disease

diseases that cannot be passed to other organisms.

Incubation period

The time between infection and the beginning of symptoms.

HPV

a virus that can infect the reproductive system. can cause cell changes that cause cancer.

Helminths

A type of worm that causes disease inside the human body. Causes Trichinosis which may reduce some autoimmune diseases.

Antigens

foreign body substances

Bacteria

Very small cells which can reproduce rapidly. They produce toxins that damage cells and tissues causing illness.

Viruses

Really small microorganisms which replicate themselves inside of infected cells. The infected cells then burst and spread them. THEY ARE NOT CELLS

Protists

Eukaryotic. usually single-celled in various sizes

Fungi

Some are single-celled, others have a body made up of hyphae.

Hyphae

Thread like structures that grow and can penetrate human skin and plants and cause disease. They also release spores.

Water transmition

pathogens can be picked up by drinking or bathing in dirty water. e.g. Cholera

Air transmition

Pathogens can be carried in droplets produced by coughing or sneezing. or pathogens that are carried in the air. e.g flu

Surface Transmition

Pathogens can be picked up from touching surfaces. e.g tobacco mosaic virus or athlete’s foot.

Tobacco mosaic virus

A virus that affects mainly tobacco and tomato plants and causes discolouration. This prevents photosynthesis but can be treated by the removal and destruction of infected leaves.

Fluid transmition

Pathogens can be transferred by exchanging fluids like breastmilk, blood or semen. e.g. HIV.

HIV

An STI that causes flu like symptoms then appears like everything is fine while it slowly destroys the immune system. It is known as AIDS once the immune system can no longer cope.

Vector transmition

Animals can spread pathogens. e.g. malaria

Soil transmition

Pathogens can live in the ground and are likely to infect plants.

Food transmition

Pathogens can be picked up from contaminated food. e.g. Salmonella.

Physical barrier

Stops a pathogen by being present

Cillia

Hair like structures in the trachea which move mucus up the throat to be swallowed. The mucus traps pathogens and is a physical barrier.

Skin

A physical barrier for pathogens

Platelets

Causes the blood to clot around a wound to prevent excess blood loss or microorganisms entering the body. Acts as a physical barrier.

Chemical barrier

Stops pathogens by killing it

Tears

eyes produce these and they contain lysozyme which breaks down bacteria. A chemical barrier

Saliva

Produced in the mouth, this kills pathogens that enter the mouth to stop them reaching the stomach. A chemical barrier

Hydrochloric acid

The stomach produces this to digest food and kill pathogens. A chemical barrier.

Microbial barrier

Stops pathogens by including other microorganisms

Intestinal Bacteria

These compete with foreign bacteria in the gut. A microbial barrier.

Waxy Cuticle

A physical barrier on a leaf. Stops pathogens and waterproofs the leaves.

Cell wall

A physical barrier of a plant cell. Made of cellulose, it stops pathogens making it into the cell.

Phytoalexins

Plant plants may produce this chemical defence when a pathogen gets past its physical barriers.

Phagocytosis

The process of certain white blood cells (phagocytes) engulfing pathogens

Antibodies

These proteins are produced rapidly by white blood cells when a pathogen enters the body. They lock onto a specific type of antigen and act as a signal for phagocytes to engulf them

Memory cells

White blood cells that remain following the removal of a pathogen so the body knows hoe to react if infected again

Antitoxins

Some pathogens produce toxins which harm the body so these are produced to bind to and counteract the toxins to limit the damage done by pathogens.

Basic hygiene

Things like regularly washing hands can reduce the spread of pathogens

Sterilising wounds

The process of killing microorganisms around a wound to prevent pathogens getting in

Living in sanitary conditions

Having access to clean water and adequate waste disposal can prevent the spread of pathogens.

Destroying infected animals

Preventing animals from spreading pathogens. Can be costly if large groups are infected.

Isolation

The prevention of an infected person passing on a disease. Typically only used by epidemics.

Vaccination (prevention)

gives the person/animal exposure to the pathogen to create the antibodies for them.

Contraception

Prevents the transmition of STIs

Destroying infected plants

Stops sources of infections in plants. Can be costly for farmers.

Crop rotation

Some pathogens are only damaging to specific plants so changing plant type in the area can stop pathogens from becoming established.

Polyculture

Preventing the spreading of diseases as many are specific so it is unlikely to spread to the neighboring plant of a different species.

Chemical control

Things like fungicides to stop the spread of pathogens. Can cause resistant strains

Biological control

The introduction of another organism to manage pathogens/pests

Vaccination

Injecting a dead, inactive or weakened pathogen to trigger an immune response and produce memory cells.

Counting cells in a sample

Some diseases effect the number of red blood cells in a volume so this can help identify the infection of a disease (A Labratory technique)

Using a microscope

This can magnify a sample and scientists may be able to identify a microorganism present that could be a pathogen. (A laboratory technique)

Growing the sample in a culture

Adding growth medium to the sample will more like allow a pathogen to be observed (laboratory technique)

Sequencing and analysing genomes

Scientists can identify the genome of certain pathogens making them be able to identify it. (Laboratory technique)

Isolation and reinfection

Essentially growing the sample in a culture however it is used in plants and a healthy plant is then infected to determine the pathogen present.

Monoclonal antibodies

Single clone antibodies that are made in a lab. Antibodies for a specific pathogen are collected (typically from animals) and combined with tumour cells. This forms a hybridoma. They bind to only one pathogen so can be used to diagnose a disease.

Hybridoma

Rapidly multiplying monoclonal antibodies that produce millions of the same antibodies.

Monoclonal antibodies - treatment

These treat cancer by targeting a specific cell. They are injected into the blood cell and bind to cells and act as signals for white blood cells to destroy them. They can also be to transport target drugs to the infected area.

Risk factors

Things that increase a person’s chance of getting a disease. These can be lifestyle, environmental or factors caused by a person’s genes.

Exercise

This increases the amount of energy used in the body and decreases the amount of fat that is stored. People who do this often are less likely to suffer from obesity or CVD

Diet

Having a balanced one of these can reduce the risk of many non-communicable diseases. However Too much of saturated fat or food in general can cause obesity and high cholesterol which can increase chances of certain diseases. Too little can cause malnutrition which can cause diseases such as scurvy.

Alcohol

This is poisonous. It is broken down by enzymes in the liver but it releases toxins. Drinking too much of this can cause increased blood pressure which can lead to CVD. This is also linked to many cancers.

Smoking

These are dangerous and addictive. They produce carbon monoxide, tar and particulates that can cause an arrangement of diseases. It is linked to CVD, an assortment of cancers, lung diseases and can cause problems for fetuses if done while pregnant.

Global lifestyle factors

Non-communicable diseases are more common in developed countries and linked to high income but these are also becoming more comm on in developing countries. Lack of exercise, high alcohol consumption and obesity are linked to high income and aren’t very likely in poor countries but smoking related deaths are more common in poor countries.

National lifestyle factors

Non-communicable diseases are the biggest cause of death in the UK. People from deprived areas are more likely to smoke, have a poor diet, not take part in physical activity and suffer from alcohol related disorders. This means that they are more likely to develop obesity, type 2 diabetes, heart disease and cancers.

Local lifestyle factors

Individual choices effect the incidence of non-communicable diseases. Choosing to drink, smoke, not exercise or have a poor diet will increase the risk factors.

Painkillers

These are drugs that ease the symptoms of a disease but don’t help to fight it.

antibiotics

These are chemicals that kill bacteria without killing body cells. Many are naturally produced by fungi and microorganisms. they can also sometimes be used to prevent certain bacterial infections.

antivirals

These are used to treat viral infections. Viruses use the host cells to replicate so they are hard to treat without damaging the hosts cells. They mostly prevent viruses from reproducing rather than killing them all together.

Antibiotic resistant bacteria

Some bacteria are naturally resistant but many strains are developed from the misuse of antibiotics. F or example if someone doesn’t finish a course of antibiotics, the most resistant bacteria will survive and have no competition. This misuse has caused antibiotics to become much less effective.

MRSA

Also known as a hospital superbug is an antibiotic resistant strain of bacteria. It can be exceedingly dangerous so doctors have to put extra care into prescribing antibiotics.

Cardiovascular diseases

Theses are diseases such as coronary heart disease that are to do with the heart and blood vessels.

Coronary heart disease

High blood pressure and cholesterol can lead to the build-up of fatty deposits in the arteries which narrows them. Over time the fatty deposits harden and form atheromas. this disease is when these atheromas restrict blood flow to the heart.

Heart attack

Atheromas can sometimes break off or damage the blood vessel, forming blood clots. These blood clots can cause a complete blockage of an artery and can lead to where the heart muscle being deprived of oxygen

Stroke

Atheromas can sometimes break off or damage the blood vessel so blood clots are formed. These blood clots can cause a complete blockage near the brain and cause this where the brain is deprived of oxygen.

Healthy lifestyle

Having a healthy diet, reducing stress, exercising regularly can reduce the chance of CVD and further complications. This can also help if you have already had problems.

Medicines

These can help control the effects of CVD. Statins can reduce cholesterol in the blood which can reduce fatty deposits however have serious side effects. Anticoagulants can make blood clots less likely however can cause excessive bleeding if the person is hurt. Antihypertensives reduce blood pressure but have side effects that include headaches and fainting.

Medical procedures

If the heart or blood vessels are too damaged this may be needed. stents are tubes that can be placed in the arteries to keep it open however they can narrow again because overtime they irritate the surrounding vessel so scar tissue is formed. If a part of a blood vessel is blocked, part of a healthy blood vessel can be taken to replace it (coronary bypass surgery). They whole heart can be replaced with a donor heart however it doesn’t always start pumping correctly and it can be rejected by the immune system.

Preclinical testing

New drugs are first tested of cultured human cells in a lab and then on live animals. This is to test if the drug is effective.

Clinical testing

If preclinical tests are successful, the drug is tested on healthy volunteers to make sure that there isn’t any dangerous side effects. Then patients with the disease are randomly put into two groups where one group is given a placebo and the other the new drug. These final tests can be blind, double blind or open label.

Blind clinical trials

These are clinical trials where the patient don’t know if they get the placebo or new drug

Double blind clinical trials

These are clinical trials where both the patient and doctor don’t know if they have the new drug or placebo.

Open-label clinical trials

This is where both doctor and patient know who are receiving the drug. This is typically used for comparing two similar drugs.

Clinical trials - ethics

Some people think giving somebody with a disease a placebo is wrong if there is a potential treatment.