Bullet point notes

 

 

CANCER

¨      A cancer is caused when a group of cells continue to divide rapidly when they don’t need to.

¨      This is caused by a change to the genes regulating cell division. The changed gene is called an oncogene (a cancer gene)

¨      The mass of additional cells is called a tumour

¨      Tumours have a rapid rate of cell division.

¨      & Abnormal cytoplasmic characteristics.

¨      They are Denser/harder/different colour than the surrounding tissues.

¨      Cells in tumours are clones and remain undifferentiated.

¨      Benign tumours are encapsulated

¨      Malignant tumours easily spread. This is known as metastases

¨      Malignant cells enter bloodstream

¨      Colonise cells in other parts of the body

 

CARCINOGENS CAUSE CANCER

Cancer

Causes

Lung Cancer             

Chemical carcinogens in tobacco smoke (e.g. tar) and air pollution.

Skin Cancer              

(Melanoma)              

UV light (Damage to ozone layer)

Colon Cancer

Chemical carcinogens e.g. Food additive/named additive

Slow gut transit time

Leukaemia

Ionising radiation

mouth/oesophagus/ larynx cancer

Caffeine/alcohol

 

Treatment

¨      Removal of tumour surgery

¨      radiotherapy

¨      chemotherapy

 

Cancers and screening

¨      Cancers are most successfully treated if detected early

¨      In the UK there are regular screening programmes e.g. Mammography/cervical smears

¨      Programmes to increase awareness of potentially dangerous changes

 

Reducing Cancer Risk

¨      high fibre/lowfat diet decreases risk of some types of cancer – breast/colon cancers

¨      some high fibre foods contain substances/ß carotene/vitamin A/vitamin C/selenium that may prevent inhibit cancer

 

CARDIOVASCULAR DISEASE

¨      Atheroma forms deposits under/in the Epithelium of arteries.

¨      If blood cells are damaged clotting factors are released.

¨      Clots in coronary arteries reduce blood flow to heart muscle therefore reduce O2 supply.

¨      Low saturated fat diets reduce build up of atheroma.

¨      High salt diets cause high blood pressure. As can stress

¨      Lack of exercise leads to:

¨                              low BMR (basal metabolic rate)

¨                              raised resting pulse

¨                              excess LDL’s

¨                              poor circulation in the heart muscle.

¨      Atheroma can lead to a loss of elastic tissue which can lead to an aneurysm – this is where a section of the artery collapses forming a balloon full of blood. If this ruptures it can have severe effects

¨      Diets high in saturated fats lead to high plasma levels of LDL’s (cholesterol), this increases the risk of atheroma development

 

VIRAL DISEASES

¨      Influenza virus enters body through respiratory surface of lungs. (infects epithelium of nasal passages, pharynx, lungs).

¨      Influenza is spread by droplet infection.

¨      Influenza virus protein coat changes when viral DNA mutates.

¨      Drug treatment difficult because viruses are inside cells therefore drugs cannot reach them. Also the drugs are likely to damage host cell as well.

¨      Retroviruses are RNA viruses

 

VACCINATION

¨      Vaccine= preparation which stimulates lymphocytes to produce antibodies;

¨      Vaccine acts as an antigen / stimulates immune response/ antibody production; to destroy pathogen before it multiplies/ causes disease;

¨      Vaccinations are not effective with 100%of recipients.

¨      Over time immunity may be reduced. This is because the memory cells that are produced in response to the first exposure can die. If this happens a booster is needed as levels of antibody may fall below immune level.

¨      New strains/mutation of pathogen may not be covered.

¨      If a high proportion of a population is vaccinated it will prevent the pathogen spreading to those not vaccinated. This is known as herd immunity.

 

TYPES OF VACCINE

¨      Killed virulent strain e.g. whooping cough/influenza.

¨      Living attenuated strain e.g. measles/mumps.

¨      Antigens separated from virus e.g. influenza.

¨      Antigen gene transferred to harmless organism e.g. Hepatitis B

¨      Toxoid eg Diptheria – antigen is toxin modify by heat still antigen but not toxic.

 

DANGERS

¨      Living viruses capable of causing disease in children with weak/slow immune response.

¨      Mutation to virulent form.

¨      Allergic reaction to a component of the vaccine.

 

MENSTRUAL CYCLE

¨      oestrogen stimulates LH production

¨      LH produced by pituitary gland

¨      LH stimulates ovulation

¨      LH stimulates formation of corpus luteum

¨      LH stimulates production of progesterone (by corpus luteum)

¨      progesterone maintains / thickens uterine lining

¨      LH inhibits FSH production

¨      without ovulation there is no egg release / no egg to fertilise

FSH

¨      stimulates growth / development of follicle;

¨      stimulates secretion of oestrogen;

¨      enhances effect of LH in stimulating ovulation;

LH

¨      stimulates (final) development of follicle;

¨      stimulates ovulation;

¨      stimulates development of corpus luteum;

¨      stimulates production of progesterone / corpus luteum produces progesterone.

Oestrogen

¨      stimulates repair / proliferation of uterine lining;

¨      (as it rises in concentration) it inhibits FSH;

¨      eventually positive feedback on FSH;

¨      (as it peaks its concentration) it stimulates release of LH:

Progesterone

¨      maintains / proliferates the uterine lining;

¨      inhibits release of FSH;

¨      inhibits release of LH;

¨      fall in progesterone results in menstruation;

¨      fall in progesterone removes inhibition of FSH and new cycle commences;

 

DEMOGRAPHICS

  • During the high stationary stage the population has a high fluctuating death rate and birth rate. The diseases are mainly infectious diseases e.g. cholera. Many such diseases are waterborne. These usually affect children most causing a high infant mortality. There is an absence of medical facilities. There is an uncertain food supply.

  • In the early expanding stage (Agricultural revolution meant) more food was available/better diet. There was also better sanitation/water supply.

  • In the late expanding stage children ceased to be economically useful/child labour laws passed/education compulsory. This made the desired family size smaller (especially when infant mortality decreased).

  • In the low variable stage there is improved contraception and women’s aspirations depend on lower family size

AGING

¨      Osteoporosis /loss of calcium from bones/ rate of cell replacement decreases/ less protein made as DNA becomes defective;

¨      fall in metabolic rate/decreased activity;

¨      loss of brain cells causes slower responses, slower learning ability, loss of memory;

¨      lower rate of nervous conduction reduces reaction time;

¨      cartilage on joints wears own/arthritis reduction in ease of movement;

¨      arteriosclerosis/atherosclerosis reduce efficiency of circulatory system

¨      reduced vital capacity of lungs/ reduced elasticity become more breathless on exertion;  

¨      Faulty copying of DNA and a lifetime of exposure to mutagens leads to accumulated genetic changes/mutations. So faulty proteins may be made

¨      cross-linking of proteins such as collagen in connective tissue, causes connective tissue to stiffen e.g. in heart, affecting resting cardiac output;

¨      other effect, e.g. wrinkling of skin/ reduced renal filtration rate/ slower circulation of blood.

¨      Body’s immune system produces antibodies against its own cells as the immune system deteriorates with age. Which also allows abnormal cells to proliferate

 

EMPHYSEMA

¨      Breakdown of alveolar walls

¨      Reduces surface area of alveoli; for diffusion of oxygen/gas exchange

¨      Walls of alveoli broken down to produce larger air spaces

¨      Diffusion of gases/gas exchange reduced/less oxygen enters blood

¨      Narrower bronchioles reduce gas flow

¨      Loss of elasticity reduces gas flow/unable to ventilate efficiently

¨      Lungs permanently inflated

¨      Less energy available/less respiration available for muscles   

¨      rate of diffusion into blood insufficient to sustain activity

 

BRONCHITIS OR EMPHYSEMA

¨      coughing attacks

¨      difficulty in breathing/short shallow breathing

¨      phlegm and coughing blood

¨      inability to sustain any physical exertion

¨      Causes include

¨      (High levels of) air pollution

¨      Smoking

¨      Industrial smoke/dust etc

 

BEHAVIOUR

¨      Inborn response/not learned/genetically determined; e.g. ability to produce a song of a specific length and containing specific notes

¨      shown by all individuals of species

 

Benefits of courtship behaviour:

¨      Species recognition;

¨      sex identification;

¨      courtship/attract a mate;

¨      synchronise sex behaviour/strengthen pair bond;

¨      territory marking/defence;

 

territories

¨      In winter maintains food supply to survive adverse conditions

¨      used for acquiring a mate/pair formation/courtship

¨      retaining the mate/pair bonding

¨      food supply for young/less competition for food

¨      protection of young

¨      less disease transmission

¨      lower chance of predation

¨      natural selection of fittest/only fittest obtain territories

 

Aggressive encounters

¨      Less chance of injury

¨      requires less energy

¨      is established territories intruder is submissive/withdraws (so fighting is not needed)

¨      fighting used when both individuals have a chance of acquiring it

¨      song/display used to advertise fitness

 

Kinesis

¨      Move faster in unfavourable environment

¨      increases chance of finding suitable environment/remaining in a favourable environment

¨      Rate of movement related to intensity of stimulus

 

Habituation

¨      Stimulus repeated many times;

¨      No reinforcement by actual predator;

¨      Nerve adaptation/ nerve impulses blocked

 

GROWTH

¨      Growth of brain and head very rapid in early years

¨      Enables scope for greater learning in childhood;

¨      allows development of complex types of behaviour;

¨      extended childhood allows longer period of learning;

¨      No need for reproductive organs to develop until adulthood;

¨      Reproductive organs develop slowly until puberty (12/13 years), when development is faster;

¨      Growth of reproductive organs at puberty allows reproductively mature individuals to be distinguishable;

¨      Reproductive organs are developing when the body/ person is mature enough to rear children

¨      delays reproduction until physical/ mental maturity reached.

 

SCREENING

  • Disease detected in early stages so treated quickly

 

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