CB5 - Health, Disease and the Development of Medicines

Health

A state of complete physical, social and mental well being.

Disease

A problem with a structure or process in the body that is not the result of an injury.

Communicable disease

Diseases that are caused by pathogens and can be transferred between people.

Non-communicable disease

Caused by a problem in the body such as a gene mutation, they are not transferable.

Role of immune system in protecting against disease

Stops things taking hold in the body. It includes physical barriers such as the skin and white blood cells that kill pathogens.

How can disease affect the immune system?

It can damage the immune system making it easier for other pathogens to cause disease, damage the body’s natural barriers allowing pathogens to enter more easily or a disease stops an organ system from working making other disease more likely to occur.

Give six examples of non-communicable disease

Kwashiorkor, scurvy, rickets, anaemia, cardiovascular disease, cancer.

Malnutrition

Health problems caused by a diet that contains too little or too much of one or more nutrients.

How can diet lead to malnutrition?

Having too much or too little of a nutrient in your diet can make you ill. E.g. lack of protein causes kwashiorkor or lack of iron causes anaemia.

Describe the link between alcohol and liver disease

Ethanol is broken down by the liver, large amounts of ethanol over a long period of time can cause diseases such as cirrhosis.

What is the effect of alcohol consumption on on liver disease at local, national and global levels?

Countries with a higher volume of alcohol consumption per year gave a higher rate of death from liver disease. It is the 5th largest cause of death in the UK, Seth’s have increased by 450% in the last 30 years. The cost of treating liver disease is £500 million and rising.

Equation for BMI

BMI = Mass/heightsquared, the result is compared to a BMI chart.

Waist:Hip ratio calculation

Waist:Hip ratio = waist measurement / hip measurement

How does obesity correlate with cardiovascular disease?

People who are obese have a higher chance of dying due to cardiovascular disease, as you become more obese the chances increase further.

How does smoking correlate with cardiovascular disease?

Smoking can cause damage to blood vessels, increase blood pressure and increase the risk of clots, all causing an increased risk of gaining cardiovascular disease.

How do exercise and diet affect obesity?

Increasing except use and controlling your diet can help to reduce the chances if you becoming obese and reduce blood pressure. Obesity and high blood pressure are risk factors for cardiovascular disease, therefore if you reduce these, you reduce the risk of cardiovascular disease.

How are high blood pressure and narrowed vessels treated?

High blood pressure - exercise more, give up smoking, use drugs to reduce blood pressure.

Narrowed vessels - a stent (small mesh tube) can be placed in the vessel to widen it.

Describe some problems and diseases caused by bacteria

Cholera - causes severe diarrhoea

TB - (tuberculosis) - Infects and damages the lungs, causing blood specked mucus, fever and weight loss.

Describe a disease caused by a virus

HIV - Destroys white blood cells in the immune system resulting in AIDS - People who develop aids are at risk of contracting other diseases due to weakened immune system.

Describe a disease caused by a protist

Malaria - transmitted by mosquitoes (vector). It multiplies in red blood cells and liver cells, these then break out of cells causing fever, weakness and sickness.

Describe a disease caused by a fungus

Chalara dieback - A disease of ash trees causing lesions on the trunk and branches, with leaves dying early and dieback of the crown.

How can signs of disease can be used to identify the pathogen?

When a person is affected with a disease, they develop symptoms associated with that disease and the pathogen that causes it. These symptoms can be matched to a pathogen and further tests can then be used to confirm the diagnosis.

State the ways in which pathogens can be spread

Airborne, waterborne, sexually transmitted, contact, food, vectors bodily fluids.

Give examples of pathogens spread different ways.

• Air - TB, Chalara Dieback

• Water - Cholera

• Sexually Transmitted - HIV

• Food - Heliobacter

• Vectors - Malaria

• Bodily fluids - Ebola

How can the spread of different pathogens be reduced or prevented?

• Air - masks, tissues

• Water - good hygiene

• Food - correctly cooking food and good hygiene.

• Sexually transmitted - contraception (condoms)

• Vectors - killing the vectors e.g. mosquito spray

• Bodily fluids - PPE like gloves and masks

Structure of a virus

They contain one or more strands of genetic material surrounded by a protein coat or capsid, different viruses may have other layers aswell.

How do viruses differ from other cells?

Viruses cannot replicate on their own like other cells, they need to invade a host cell and use their cell components to make a new virus cell.

Describe the lyric pathway of a virus life cycle

Virus attaches to a host cell and injects its genetic material, viral genetic material forms a circle, new viral genetic material and proteins are produced and assembled, cell lyses releases the viruses and cycle starts again.

Describe the lysogenic pathway of a virus life cycle

Virus attaches to bacterial cell and injects its genetic material, viral genetic material forms a circle, inserts itself into bacterial chromosomes, bacteria reproduces normally replicating viral genetic material, this can happen many times, viral genetic material sometimes splits of starting a lytic cycle

Compare and contrast the lyric and lysogenic pathways.

Lytic cycle, virus enters cell and causes the cell to make lots of new viruses which leave the cell.

Lysogenic cycle, virus inserts its genetic material into the cells genetic material so that it is replicated every time the cell replicates, each new cell contains the genetic material of the virus.

Cross sectional area equation

CSA = 🥧r squared

Physical barriers of plants to pests and pathogens

Waxy cuticle on leaves and bark on stems.

Chemical defences of plants to pests and pathogens

Plants produce chemical substances such as poisons or insect repellents. Wild potatoes release a substance when attacked by aphids which replicates aphids warning chemical for being attacked by predators, whereas plants like foxglove release poison all the time.

How can plant chemicals be used to treat human diseases or symptoms?

Aspirin used as a pain relief comes from salicylic acid produced by willow trees. Artemisinin produced by wyrmwood helps destroy malaria. These can be replicated and improved in the lab.

Examples of aseptic techniques

Autoclaves to sterilise equipment and growth medium (agar), flaking the necks of bottles etc.

Why is aseptic technique used during the culture of micro organisms?

Tests in bacterial abs human cells need to avoid contamination by other microorganisms in the air, aseptic techniques help to avoid this.

How can the spread of STIs be reduced and prevented?

Avoid direct contact with sexual fluids using a condom, ensuring needles aren’t shared.

Examples of physical barriers

Skin, mucus, ciliates epithelial cells

Examples of chemical barriers

Lysozyme and stomachs acid

Stages of development of a new medicine

• 1 - test in cells or tissues in a lab to see effects on that tissue.

• 2 - test on animals to see effects on whole body.

• 3 - Clinical trials on a small number of healthy patients.

• 4 - Test on patients who have the disease rhe medicine will be used for.

Why is each stage of new medicine development needed?

• 1 - to ensure drug does it’s intended function with out serious negative side effects.

• 2 - to see if the drug has side effects elsewhere in the body without risking human lives.

• 3 - to check the drug isn’t harmful to humans without risking using iron people who are already ill.

• 4 - to check the drug works on humans worth the disease.

Antibiotic

Drugs that either kill a bacteria or inhibit their cell processes to stop them growing or dividing.

Why are antibiotics useful?

Antibiotics target processes specific to bacteria m, therefore they can destroy the bacteria without harming human cells.

Why can antibiotics be used for anything other than bacteria?

Antibiotics target processes specific to bacteria, these processes are not conducted by the other pathogens so antibiotics will have no effect on them.

How do physical barriers protect the body?

Skin blocks entry of pathogen.

Mucus traps pathogens and dust which can either the coughed up or swallowed and destroyed by stomach acid.

Associated epithelial cells help to move mucus up or down the throat.

Describe how chemical barriers protect the body

Lisozymes are released in tears saliva and mucus to help breakdown pathogens.

Stomach Acid - ph2 acid helps to destroy pathogens.

How does the immune system protect the body by attacking pathogens?

The immune system produces white blood cells which attack pathogens. Phagocytes engulf pathogens and digest them using digestive enzymes. Lymphocytes produce antibodies and antitoxins to help neutralise pathogens.

How do antigens trigger the release of antibodies and the production of memory lymphocytes?

Antigens specific to the pathogen are found on their surface. These are recognised by lymphocytes which can produce a specific antibody to destroy that pathogen. Some of these lymphocytes become memory cells which remember the antibody next time the pathogen invades and can produce a quicker response.

Role of antibodies in immune response

Antibodies that are complementary to specific antigens are produced. These can either destroy the pathogen, clump them together to help phagocytes digest them, cause rapid multiplication of the antibody producing cells or trigger the formation of memory cells.

Role of memory cells in triggering a secondary response

The first time a pathogen invades the body memory cells are produced that are able to recognise the pathogen next time it invades the body and producing much quicker and more potent immune response reducing your sentence or stopping them altogether.

How does immunisation protect against infection by pathogens?

Immunisation involves exposing a person to a dead or inactive version of the pathogen. This means the white blood cells can recognise the antigen and produce memory cells against it. This means if you do contract the disease, you are able to produce a quicker and more potent response, hopefully stopping you from becoming ill.