Solvents and alcohol
Solevents are Depressants that give off all kinds of vapours
Physical Effect- can cause damage to the lungs, brain and kidneys
Mental Effects- slow down reaction times by lowing down transmission of a message across synapses, causes hallucinations, change behaviour and personalilty.
Alcohol is a depressant that contains the chemical ethanol
Physical effects- can lead to brian damage and liver damage, because the liver removes alcohol from the body. Excess can lead to unconsiousness, coma and death.
Mental Effects- slows down reaction times by slowing down transmission of a messgae across synapses, can cause depression, can lead to loss of inibitions and self-control.
Tobacco and Cancer...
Tobacco tar and nicotine produces carbon monoxide when smoked.
Physical effects- carbon monoxide is absorbed by haemoblobin in red blood cells more easily than oxygen. Long term can lead to; emphysema:aveoli becoming damaged due to excessive coughing, cilia stop beating cauing mucus to build up, chest infections, damage to the circulatory system, damaged blood vessels which can lead to heart attack, strokes and heart disease, tar can cause cancer, increase heart rate and blood pressure
Mental effect- it is addictive.
Cancer- the tar in cigarette smoke contains carcinogens (chemicals that cause cancer) These can cause cells to mutate and divide uncontrollably, which can form tumours. The tar can cause cancer of the lungs, throat, mouth and stomach.
Emphysema and drug effect...
Emphysema - the walls of the aveoli in the lungs break down, reducing the surface area for gaseous exchange. This results in the sufferer having to breathe more deeply in order to compensate for the reduced surface area. The forced breathing reslts in the chest becoming barrel-shaped.
Drug- are chemicals which alter the way the body works. Some drugs are obtained from living things (often plants) whilst others are synthetic (man-made)
Paracetamol- is commonly-used painkiller and anti-flammatory, which also helps to lower body temperature. However, great care must be taken not to exceed the recommended dosage which could lead to liver failure or death.
Missues of drugs can cause physical and mental problems. Sharing unsterilised needles when injecting illegal drugs can lead to an increased risk of spready viral infections such as hepatitis and HIV.
Drugs and Pathogens + Disease...
Cannabis comes from cannabis plants. Opiates are drugs that come from poppy plants.
Both relieve pain, but are classed as illegal drugs.
A pathogen is a microorganism that causes a disease. There are three main types: bacteria, viruses and fungi.
Bacteria- Treated by antibiotics eg Tuberculosis, conjunctivitis
Fungi- Treated by anti-fungal medicine and antibiotics eg athletes foot, ringworm
Viruses- Very difficult to treat- eg flu, chicken pox, HIV.
Transmission of Microorganisms
Pathogens (germs) can be transmitted from one person to another in two main ways;
Direct contact- horizontal transmission- eg touching an ill person.
Vehicle transmission- eg touching an ill persons things
Some diseases cabn be spread directly from mother to foetus.
Indirect contact- many illnesses are spread through coughing or sneezing.
Some diseases are transmitted by a third party: another organism spreads the illness/disease. For example if someone who has malaria is bitten by a mosquito, the mosquito sucks up a drop of blood. It then flies off and bites another, healthy person. It transfers some of the ill person's blood to the healthy person. The healthy person then has malaria. The mosquito is a vector of malaria. Malaria is, therefore, a vector-borne disease.
Keeping Microorganisms out...
Lines of defence against invading microorganisms
- physical and chemical barriers
- non-specific defences: white blood cells and inflammatory response
- specific defence: white blood cells and the immune system
Nasal Hairs- trap dust and prevent it being breathed into the lungs
Lysozymes (found in tears) when bacteria land on the wet surface of the eye they are killed by lysozymes.
Skin- prevents entry of disease-causing microorganisms, puncture due to injury, friction or continued flexing.
White blood cells...
...are able to change shape and move out of the blood through the capillary walls into surrounding tissues and the site of the infection. This type of white blood cell is called a phagocyte. Phagocytes ingest the microorganisms and eventually die, forming pus.
White blood cells recognise the microorganisms as antigens (foreign bodies) and produce antibodies to destroy them. We feel ill because it takes time for the white blood cells to produce antibodies to kill the microorganisms.
The production of antibodies is much faster if a person has already had the infectious disease. The white blood cells 'remember' the antigen.
White blood cells also produce anti-toxins which neutralise harmful toxins produced by microorganisms.
TB is a disease caused by the bacterium Mycobacterium tuberculosis. Any part of the body can be affected, bt it usually infects the lungs.The disease can be passed on through coughing and sneezing.
New drugs and medicines have to be thoroughly tested and trialled before they can be prescribed by doctors. The three stages;
Is is toxic? Is it safe for humans? Does it work?