Infectious diseases are generally caused by microbes known as pathogens. Pathogens invade the host and can cause changes in the body that stop parts, or all, of the body working correctly. Pathogens contain antigens that are made of proteins or polysaccharides. The bodies immune system reacts to these antigens to try to attack the pathogen and protect the body. The most common pathogens include viruses and bacteria. Other pathogens include worms, fungi and lice.
Bacteria are small, single celled organisms that can be seen under a light microscope. Bacteria are found everywhere and some are important and beneficial to the human body.
1)what is an agar plate?
It is a sterile dish that contains agar mixed with nutrients, which is used to grow microorganisms..
What does the agar gel contain?
A gel like substance made from seaweed, commonly used as a growth medium for microorganisms.
* 2) what things will grow in agar
Plants are commonly grown in agar, but without sterile conditions bacteria and disease can also grow and become potentially harmful.
3) find out how the microbes grow in the agar ie how long do they take to grow and if they continue growing
4)how is this information used in medical practice
1) Do all white blood cells (WBC) work the same?
2) How are WBC transported around the body?
3)What are the two divisions of the immune system?
4)When do WBC numbers increase in the body?
5) Why does the body temperature increase (fever) during infection?
* WBC| * Where are they found| * How do: they work to get rid of microbes| * Macrophage| * | * |
* neutrophil| * | * |
* eosinophil| * | * |
* Dendritic cells| * | * |
* 8 - cells| * | * |
* T - cells| * | * |
Barriers to disease and infection.
Skin – epithelial lining
digestive tract – epithelial lining
respiratory tract – epithelia lining
diseases cause harm to the body and can potentially kill us. Diseases change the normal physiological conditions in the body.
The defence force
The first line
Skin – prevents entry of microbes by placing a physical barrier to “larger” airborne particles.
* Nasal hairs – provide a physical barrier to “larger” airborne particles *
* chemical defence
* body fluids – saliva, tears contain chemicals to clean *
* acid – in the stomach breaks down the microbes
* acidic mucus – makes it difficult for microbes to grow *
* The second line
* Some microbes make it past the first line of defence.
* Affected tissues swell, become red and hot. This is called inflammation. Damaged cells release chemicals that increase blood flow to the area which causes swelling and redness. The blood contains both red and white blood cells. The white cells are attracted to the damaged cells and help to protect the body by removing the foreign microbes. Many of these white cells are killed and the combination of dead white cells, dead skin, foreign particles form pus. *
* The last line
* There are many different types of white cells. Some are found in the lymph system and some in the blood. Swollen glands are an indicator of infection as the body tries to reinforce it defence force by increasing the number of lymphatic cells (white cells) and releasing then into the blood stream to fight a microbe that has breached the first and second line of defence. Glands are lymph nodes that filter fluids and trapped foreign particles so the white cells can destroy them. *
* List 5 types od white blood cells ( at least 2 lymphocytes) where they are found mainly and how they protect the body.
infectious disease may be passed on in a number of different ways. Stopping the spread of disease requires us to understand how the disease is transmitted.
Diseases can be spread by:
1) vectors – vectors are objects that transport disease from the host organism to the new unaffected person. These include mosquitos, flies, rats, mice
2) direct contact – coughing and sneezing causes small airborne droplets which are transported over short distances. These land on surfaces which an then be picked up. Touching sores or infected areas can also transfer diseases like herpes virus
3) water – man pathogens can live in water. Consumption of contaminated water causes many diseases especially in areas with poor hygiene standards.
1. how do most people catch this bacteria?
It is a bacteria that is found on the skin or in the nose of healthy people. It may occasionally get into the body. 2. where do most people carry these bacteria?
3. why is MRSA such a dangerous infection?
4. what are the differences between a virus and a bacteria in terms of remaining alive? 5. what are 5 ways a person can catch MRSA?
6. what internal organ is most affected by MRSA?
7. how can we prevent the spread of MRSA in the hospital ( 3 actions )? 8. if we developed an advertising campaign to prevent the spread of MRSA what would be in it?
* Virus| * Bacteria|
* a cellular * no cell. * - invades host cell to make more viruses| * - cellular – single celled * - fission – cell grows then splits into two new cells| * | * |
HOW TO STOP DISEASE SPREADING
Treat the water
* keep individuals with disease away from general population * quarantine laws protect Australia from foreign diseases
Q1. Identify four factors that can lead to cancer
Cigarette smoking, exposure to the sun, poor diet, exposure to chemicals, genetic predisposition.
Q2. Cancer can be treated in a variety of ways. Describe three of these.
Q3. Explain why metastases make it difficult to treat cancer it is when cancerous cells find their way into the circulatory or lymph systems and travel to other parts of the body. This is then hard to treat once secondary cancer sites develop.
Drugs, alcohol, smoking and disease
a drug is any substance that has the ability to alter a persons body chemistry. Psychoactive drugs are these that alter mood. Drug use may be necessary to help in some diseases and is normally taken in a controlled does to limit side effects. Drug abuse is when a drug is used in a negative way. Some use drugs as a so called ‘’recreation’’ without understanding the potential hazards damage they cause in the body.
Alcohol and smoking cigarettes are common drugs that are freely available in Australian society but also caused significant damage to individuals and society. Approximately 7% of male deaths, 4% of female deaths can be attributed to alcohol. Alcohol is a ‘depressant’ which means it slows down the nervous system. The effects of alcohol are dependant on the amount consumed.
Small amount – warm, sense of wellbeing
Moderate amount – slowed thinking, slurred speech
Large amount – loss of consciousness death.
Binge drinking is particularly harmful as the body has no time to respond. Longer term alcohol abuse has significant impact on disease.
Major organs can be damaged such as liver, kidney, heart and brain cells. Melanisation is also an use in alcohol abuse. Significant changes in smoking habitats has seen an increase in female smokers. Cigarettes are appetite suppressant and are highly addictive. Smokers are more likely to have:
- heart attack
- constriction of blood vessels
- cancer (especially, throat and lung)
- early death
- obstructive long diseases
- birth weight issues
- bad breath and stained teeth/fingers
carbon hydrogen oxygen
water carbon dioxide ozone
nucleus cell membrane mitochondrion
blood cell sperm cell neuron
nervous tissue muscle tissue connective tissue
liver kidney heart
skeletal system muscular system nervous system