Health and disease Flashcards
What are communicable diseases?
Diseases that can be spread between induviduals
SB5a Health and disease
Define the meaning of Health
- Health is a state of complete physical, mental and social well-being. ( as defined by the World Health Organization )
SB5a Health and disease
Explain why the presence of one disease can lead to a higher susceptibility to other diseases
- A disease may damage the immune system, making it easier for other pathogens to enter the body. ( E.g. HIV )
- A disease may damage the body’s natural barriers and defences, allowing pathogens to get into the body more easily.
- A disease may stop an organ system from working effectively, making other diseases more likely to occur.
SB5b Non-communicable diseases
Describe the different diseases that can be caused by malnutrition.
1. Kwashiorkor
- Caused by a lack of Protien
- Symptoms include; enlarged belly, small muscles, failure to grow properly.
- Good sources for diet include; meat, fish, dairy, eggs, pulses
2. Scurvy
- Caused by a lack of Vitamin C
- Symptoms include; swelling and bleeding gums, muscle and join pain, tiredness.
- Good sources for diet include; citrus fruits ( e.g. oranges ) and vegetables.
3. Rickets/Osteomalcia
- Caused by a lack of Vitamin D and/or calcium
- Symptoms include; soft bones, curved leg bones
- Good sources for diet include; Vitamin D: oily fish. Calcium: dairy products
4. Anaemia
- Caused by a lack of iron
- Symptoms include; smaller and fewer red blood cells, tiredness
- Good sources for diet include; red meat, dark green leafy vegetables, egg yolk
SB5b Non-Communicable diseases
Describe the effect of Alcohol on liver diseases.
- Ethanol, found in alcholic drinks, is a drug because it changes the way our body works.
- Ethanol is broken down by the liver, and a large amount of ethanol taken over time can lead to liver disease, including cirrhosis
- A cirrhotic liver does not function well and can result in death.
SB5c Cardiovascular disease
Describe the effect of;
A) Diet on cardiovascular diseases
B) Smoking on cardiovascular diseases
A) A diet that is high in sugars and fats can lead to obesity, where large amounts of fat are formed and around the organs.
- To much fat can increase the risk of cardiovascular disease.
- Cardiovascular disease is a result of the circulatory system functioning poorly.
B1) Tobacco smoke contains many harmful substances that can damage the lungs when breathed in.
- Some of these substances are absorbed from the lungs into the blood & transported around the body.
B2) These substances can damage the blood vessels, increase blood pressure, make blood vessels narrower and increase the risk of blood clots forming
- All of which, can lead to cardiovascular disease
B3) Smoking also causes;
- Damage to the alveoli so the surface area of the lungs decreases, meaning less oxygen can be absorbed
- Fatty deposists build up in the arteries
- Nicotine raises heart rate and blood pressure.
BMI = mass ( kg ) / height^2 ( cm )
SB5c Cardiovascular disease
Describe some different method of treating Cardiovascular diseases.
1. Lifestyle - A doctor may advise a patient to reduce the amount of sugars/fats in their diets or reccomend them to start excercisin and give up smoking.
2. Surgical procedures - A narrowed blood vessel can be widened using a stent at the narrowest part to hold it open.
- Blocked arteries in the heart can be bypassed by inserting other blood vessels so that the heart tissue is supplied with oxygen & nutrients again.
3. Lifelong medication - Patients who have these operations may have to take medicines for the rest of their lives to prevent a heart attack or stroke.
What are non communicable diseases?
-Diseases that cannot be transmitted between induviduals
-If you are infected by one disease, you are more susceptible to others
What are pathogens?
Organisms such as viruses, protists, bacteria and fungi that cause communicable diseases
A disease caused by Virus (viral):
Ebola
- causes haemorrhagic fever
- spread via bodily fluids
- transmission can be reduced by isolating infected individuals and sterilising any areas where the virus may be present.
Name a fungal disease:
Chalara Ash Dieback
- symptoms include bark lesions and leaf loss
- fungus is carried through air by wind
- transmission reduced by removing young, infected ash trees and replanting with different species
Name a disease caused by a protist
Malaria
- effects of malaria include damage to red blood cells and liver
- mosquitoes act as vectors - they pass on the protist to humans but don’t get the disease themselves
- mosquito nets and insect repellent can be used to prevent mosquitoes from biting
Name some bacterial diseases:
Cholera:
- Causes diarrhoea
- Spreads through contaminated water sources
- Transmission can be reduced by making sure that people have access to clean water supplies
Tuberculosis:
- Causes lung damage
- Spreads through the air ( airborne )
- Transmission can be reduced with face masks.
Stomach Ulcers:
- Caused by Helicobacter
- Spread when people touch other people’s food after touching their mouth, or after going to the toilet.
- Humans may develop sore areas called ulcers, where the bacteria attacl the stomach lining
- Transmission can be reduced by; 1. Not touching other people’s food after touching your face, 2. Washing your hands after using the toilet
An example of an STI:
HIV
- Human Immunodeficiency Virus - it kills white blood cells, which are really important for immune response
- HIV eventually leads to AIDS, where an infected persons immune system fails
- Spread via bodily fluids (e.g blood, semen, vaginal fluids).
What is a virus?
- A protein coat around a strand of genetic material
- have to infect host cells in order to reproduce
The lytic pathway (step-by-step)
1. Virus attaches itself to a specific host cell and injects its genetic material into the cell
2. The virus uses proteins and enzymes in the host cell to replicate its genetic material and produce the components of new viruses
3. The viral components assemble
4. The host cell lyses, releasing the new viruses, which infect , more cells
The lysogenic pathway
1) The genetic material is incorporated into the genome of the host cell
2) The viral genetic material gets replicated along with the host DNA every time the host cell divides - virus is dormant and no new viruses are made
3) Eventually a trigger (e.g the presence of a chemical) causes the viral genetic material to leave the genome and enter the lytic pathway
Example of plants physical defenses:
- Most plants and leaves have a waxy cuticle, providing a barrier to stop pathogens/pests.
- Also stops water collecting which reduces the risk of infection by pathogens transferred by water
- Have cell walls made from cellulose which are difficult for pests or pathogens to penotrate.
- Layers of dead cells around stem ( e.g bark )
- Some plants have spines or hairs which deter pests.
Examples of chemical defenses in plants:
- Produce chemicals called antiseptics which kill bacterial and fungal pathogens.
- Produce chemicals to deter pests from feeding on leaves
- These can be used as drugs to treat human disease (e.g Qunine and Aspirin)
- Plants may produce chemicals that result in them having unpleasent taste or smell.
SB5g Plant defences
Describe how certain chemicals from plant can be used to relieve symptons/diseases.
1. Aspirin is commonly used to control symptons of pain or fever
- Aspirin was originally produces by salicylic acid, which is made by several plants.
2. Artemisinin is another example, this kills the Plasmodium protists that cause malaria.
- It was originally extracted from the wormwood plant.
SB5h Plant diseases
Describe different ways plant diseases can be detected and identified.
1. Cameras on drones can be used to find out if plants are under stress.
- Plants show signs of stress whenever; conditions are not good for growth, too much/little water, soil lacks nutrients, or plants are being attacked by pests.
2. Identifying - can be done by looking for visual symptons; changes in growth, changes in colour or blotching of the leaves or lesions on stems or leaves.
- Symptons can then be checked agaisnt photos etc
3. If symptoms looked too similar, distrubtion analysis could be used, which looks at where the the damaged plants occur.
- Flooding, droughts or lack of soil nutrients will create similar symptons to plants in the area.
- Diseases spread by wind will affect plants in a large area.
- Soil pathogens are usually only found in small areas.
lesions - Areas of damage
SB5h Plant diseases
Describe how soil samples ( testing ) can be used to produce a diagnosis for plant diseases.
1. These tests can include trying to grow a pathogen from damaged crop plants, or using technology to identify the presence of genetic material from a pathogen
2. When farmers send damaged plants in for testing, they will also send a report on other observations they have made.
- They may also send soil samples to be tested for nutrients and toxins.
Human physical barriers to stop pathogens entering the body:
- Skin act as a barrier to pathogens, if damaged, blood clots quickly seal cuts. Skin is also water proof and had dead cells on its surface.
- Hairs and mucus in nose trap particles that could have pathogens
- Ciliated cells found within the trachea and bronchius move mucus across the surface of the cells, moving pathogens out of the body into the throat.
- Tears wash pathogens away
- Ear wax traps pathogens
- Nasal hairs trap pathogens
- Blood clots / scabs cover wounds to prevent pathogen entry.
Chemical barriers to stop pathogens entering the body:
1. Some of the cells lining the stomach produce hydrochloric acid, reducing the ph of the stomach to about 2. At this acidity, many pathogens are destoryed. ( Certian types like Helicobacter pylori can survive )
2. The skin contains glands that secrete substances onto the skin, one of which being lysozome which is an enzyme that breaks down the cell wall of certain bacteria.
3. Lysozome is secreted in tears, saliva and mucus, where it helps to protect the thinner surfaces of the body.
