DISEASE
CAUSES
Testicular cancer
(common in young and middle-aged men)
Prostrate cancer
(common in men over the age of 60 years)
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detected as a hard (usually painless) swelling on the side of a testis
TREATMENT/CON TROL •
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surgical removal of the testis radiotherapy or chemotherapy
prostrate gland tends removal of the to enlarge and prostrate gland removal of testes interrupt the ow and treatment of urine, causing with oestrogen frequent urination (since testosterone may promote the growth of the cancer) •
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(linked to obesity)
en should check their testes regularly and men aged over 60 should report any symptoms of urination to their doctor!
Ovarian cancer
Cervical cancer
Asthma
(common in older women who have not had children)
any growths in the ovaries are cysts that are not harmful! "ome growths are cancerous but there are no symptoms until the ovarian cancer is large and has spread to the uterus, where it causes pain!
(common in
$o symptoms until cancer has spread
younger women who are se#ually active, have had se#ually transmitted infections or an early pregnancy) (linked to obesi ty) •
smoke, e!g! from cigarettes
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breathlessness di%culty e#haling
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cancer may be removed in an operation drugs (chemotherapy)
detection by taking cervical smears and looking for precancerous cells radiotherapy if the cancer is not far advanced steroid drug, e!g! the drug,
DISEASE TRANSMISSION Leptospirosi bacterium passed from animals to humans s !"eil#s &he bacteria pass out in the urine and may come into contact $isease% with breaks in the skin, the membranes of the eyes or into the nose! 'rinking infected water or eating contaminated food odents are vectors Den&ue irus '*$-+ to '*$- 'ever Aedes aegypti mosquito bites and drinks the blood of an infected person and passes the virus on in its saliva (astroenteri acterium of the Salmonella group tis .ousey picks up infected material from food or from faeces, and then passes it on to human food as it feeds &he mouthparts of a housey consist of a long, grooved tongue with two channels, one which releases saliva and the other channel sucks up digested foodstu/s! 'uring feeding, the y squirts saliva containing digestive enymes to partially digest its food and the resulting liquid is sucked up into the y1s intestine where digestion is completed! &he decaying remains of dead animals, dung and the remains of food on rubbish tips on which the houseies feed contain the microbes which cause typhoid, typhus, cholera, dysentery, tuberculosis and gastroenteritis, together with some tapeworm and threadworm eggs! &hese microbes and eggs stick to the housey1s feet, mouthparts and body and may be spread as the housey settles on human food and drinks! infectious diseases, e!g! cholera and typhoid non-infectious diseases, e!g! food intolerance causes inammation of the stomach and2or intestine and diarrhoea 3revention4 good sanitation (keep human wastes from drinking water), e!g! 5n many countries, sewage is carried by a drainage system to a sewage works! &he water supply is treated to kill potential pathogens and is distributed in a network of pipes! • •
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ost chronic diseases cannot be cured but can be treated to reduce symptoms! eneral prevention includes4 •
balanced diet
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e#ercise (improves circulatory, skeletal and muscular systems as well as improves mental health) not smoking drinking in moderation or not at all
esponse system4 +! &he epidermis of the skin is a barrier against the entry of pathogens! "ebum secreted by the sebaceous glands in the skin acts as an antiseptic! .ydrochloric acid in the stomach and lactic acid in the vagina provide acidic conditions which prevent the growth of bacteria! ucus is secreted by cells of the respiratory tract onto cilia which move it away from the lungs! 7ysoyme in many body secretions, e!g! tears, is an enyme which breaks down the cell walls of bacteria! 9hen pathogens get through these defences, phagocytes in the blood may engulf and destroy them! 9hen viruses, e!g! common cold and u, enter cells, the infected cells secrete chemicals to warn other cells of the invasion! &hese are nonspeci:c defences! &he body has an immune system consisting of tissues, cells and molecules dispersed throughout the body to produce speci:c defences if pathogens breach the second line of defence! &hen, the phagocytes 1cut them up1 and 1show1 them to lymphocytes which recognise the antigens and multiply by mitosis! &hese lymphocytes become :lled with endoplasmic reticulum and ribosomes so that they secrete protein molecules, called antibodies, into the lymph and blood! &he forked end of the antibody recognises and binds to the surface antigen to label it! &he other end acts as a signal to phagocytes or &-lymphocytes! &hese labelled antigens stick together in clumps to be ingested by phagocytes, are destroyed by &-lymphocytes which burst their membranes or are destroyed by the antibodies themselves which destroy the pathogen1s cell walls or membranes! =ntito#ins are antibodies that combine with the to#ic waste products of bacteria and neutralise them so that they have no e/ect, e!g! bacteria of tetanus and diphtheria! ?ther lymphocytes are activated to patrol the body looking for infected cells, which they destroy to stop the production of pathogens! "ome lymphocytes remain as memory lymphocytes which can recognise a second infection and destroy pathogens before symptoms even develop! − − −
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=n antigen is a protein or carbohydrate on the surface of a pathogen which provokes the immune system of the host! =n antibody is a A-shaped protein produced by lymphocytes which are able to recognise, bind to and destroy pathogens! =n antito#in is an antibody which neutralises to#ic waste products of bacteria (to#ins)!
DRU( "edative or tranquiliser, e!g! alium, 7ibrium
E))ECT slows down bodily functions to reduce an#iety induces sleep overdose of sedatives may be fatal especially if taken with alcohol alium makes it more di%cult for neurotransmitters to cross synapses relieves depression may be taken for other conditions, e!g! pain relief severe side e/ects even if taken within the prescribed dose, e!g! untypical violent behaviour relieve pain by interfering with the production of chemicals that cause inammation overdose of aspirin may cause bleeding of the stomach overdose of paracetamol may lead to liver failure and death
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=ntidepressant, e!g! 3roac
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3ainkillers, e!g! 3aracetamol, =spirin, 5buprofen =ntibiotics
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=nti-fungal drugs =ntiviral drugs
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"timulant, e!g! cocaine, amphetamines (such as ecstasy)
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used to control the spread of bacterial diseases in the body kill bacteria or stop them from reproducing target processes such as cell wall synthesis, protein synthesis in ribosomes and movement of substances across membranes controls the growth of fungi, e!g! thrush and ringworm interfere with enymes that are only found in fungi and not in human cells control the spread of viral diseases, e!g! genital herpes prevent the production of viral genetic material interfere with viral protease enymes greater alertness and wakefulness "timulants speed up (promote) the action of the nervous system Bocaine is highly addictive! *cstasy4 enables dehydration may lead to death or disability, due to high body temperatures or rapid dehydration reduces the number of nerve cell connections in the brain in the long-term, causing memory loss and inability to perform
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.allucinogen, e!g! 7"', mariCuana
'epressant, e!g! heroin (obtained from opium poppies), alcohol
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speci:c tasks a/ects coordination is especially dangerous for persons with high blood pressure, heart problems or epilepsy, being a stimulant causes changes in consciousness that users compare to having dreams or going into trances by upsetting the normal memory pathways in the association areas so that a normal stimulus may connect to an unusual response and the user may e#perience hallucinations (vivid waking dreams) reduce feelings of an#iety provides pain relief may induce sleep lowers blood pressure, heart rate and breathing rate 9ithdrawal symptoms of heroin from as little as four hours without the drug include4 vomiting trembling profuse sweating severe abdominal pain =lcohol4 a/ects emotional centres in the forebrain, acts as a depressant, overruling normal social constraints depresses the life-support centres in the medulla in high concentrations, stopping breathing, causing brain damage or even death reduces the e/ect of ='. on the kidney, dehydrating the body as water is not reabsorbed and causing a headache can upset normal sleeping patterns by reducing the levels of a 1calming agent1 in the brain slows down nerve impulses in peripheral nerves, causing slower reactionsD a/ects nerves that control blood ow to the skin, dilating skin blood vessels, causing ushing of the skin and hypothermia at low environmental temperatures stimulates se# organs and cause them not to work well has cardiovascular e/ects, e!g! anaemia (alcohol poisons bone marrow) and increased deposits of fat in coronary arteries causes irritation of the intestines, causing indigestion, nausea, diarrhoea and ulcers
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has liver cells work harder to deto#ify alcohol, damaging cells lining blood vessels and causing cirrhosis of the liver crosses the placenta in pregnant women, impairing the development of the development of the child1s nervous system, called foetal alcohol syndrome increases the risk of cancer of the tongue and oesophagus causes delirium tremens4 withdrawal symptoms, e!g! tremors, high pulse rate, sweating and visual hallucination, which is treated with sedatives and multivitamins
