Describe the events in the development of lung cancer[8] #
- carcinogens cause mutations;
- e.g. UV light/tar/X-rays/asbestos;
- oncogenes transformed by carcinogens;
- cancerous cells do not respond to signals from other cells;
- uncontrollable cell division/mitosis;
- cancerous cells not removed by immune systems;
- absorption of nutrients from other surrounding cells;
- tumour gets bigger;
- begnin tumours;
- malignant tumours;
- tumour supplied with blood and lymph vessels;
- metastasis;
- blockage of intestines/lungs/blood vessels
- secondary growth;
Describe how emphysema and chronic bronchitis affects the gaseous exchange system[8] #
- Emphysema
- digestion/destruction of elastin
- by phagocytes/elastace
- bursting of alveolus
- decrease in surface area for gaseous exchange
- lack of air spaces during breathing out
- Chronic bronchitis
- enlargement of mucus glands in the trachea and bronchi;
- increased mucus secretion;
- destruction of cilia;
- epithelia replaced by scar tissue;
- thickening of smooth muscle;
- blockage of airways or passages by mucus
Discuss the short term effects of physical exercise on muscles and gaseous exchange[8] #
- Effects on muscles
- Increased blood supply to muscles
- Muscle respire anaerobically (to produce ATP)
- Muscular fatigue may occur/muscle fail to contract and relax repeatedly with the same force
- Muscle fibres may be damaged (due to overstretching)
- Depletion of glycogen stores
- Effects on gaseous exchange
- Stimulation of the SNS and secretion of adrenaline
- Vasodilation of arterioles/capillaries
- Due to greater rate of blood flow through capillaries/due to greater cardiac output
- Increase in ventilation
- Dilation of bronchioles
- Reduced resistance to air movement
Effects of tar in tobacco smoke on the gaseous exchange system[8] #
- stimulates extra cell division +thickening of the epithelium;
- which may develop into a tumour;
- tar coats the epithelium lining of the breathing tubes;
- causing irritation of the epithelial cell;
- epithelia replaced by scar tissue;
- production of excess mucus by the goblet cells;
- paralysis of cilia;
- build up of pathogens + mucous;
- smoker‘s cough/emphysema;
- reduced surface area for gaseous exchange;
Effects of tar and carcinogens in tobacco smoke on the gaseous exchange system[8] #
- paralyses/destroys cilia;
- stimulates over secretion of mucus by goblet cells;
- growth of scar tissue;
- leads to development of bronchitis/emphysema;
- epithelial lining coated with tar;
- carcinogens;
- combine with DNA/chromosomes of cells in the bronchial epithelium/lining;
- leading to tumour growth/growth in the epithelium/lining;
- bronchial carcinoma;
- malignancy;
- metastasis/secondary tumours;
The effects of nicotine and carbon monoxide on the cardiovascular system #
- Nicotine
- causes constriction of arterioles;
- stimulates release of adrenaline;
- increase heart rate/blood pressure;
- reduced peripheral blood flow;
- less blood flows to the skin/hands/feet (blood supply to extremities reduced);
- increased stickiness of blood platelets;
- increases cholesterol levels;
- which may lead to atherosclerosis;
- due to formation of atheromas
- increases likelihood of thrombosis;
- Carbon monoxide
- combines with haemoglobin;
- to form a stable compound;
- haemoglobin has a greater affinity for carbon monoxide than oxygen;
- decreases oxygenation of blood/lead to shortage of oxygen;
- increases strain on the cardiovascular system to supply oxygen to all tissues;
- blood vessels more vulnerable to the development of atherosclerosis;
- may lead to CHD/stroke
Describe how atherosclerosis develops[8] #
- onset may be caused by damage to lining of artery;
- smooth muscle cells proliferate at site of damage;
- phagocytes invade breaks and release growth factors and stimulate the growth of smooth muscle cells/accumulation of cholesterol
- atherosclerosis starts as fatty streaks;
- fatty substances deposited in inner coat/lining of arteries;
- deposited in inner surface of artery;
- also high proportion of cholesterol;
- usually large arteries;
- deposit is called atheromas;
- (uneven) patches develop called plaques/atheromatous plaques;
- causes walls of artery to thicken/lumen narrow;
How you might tell whether a drug is socially acceptable or not[6] #
- survey of people‘s attitudes to the drug;
- legislation i.e. laws governing sale and use of drugs;
- e.g. banned by law;
- the number of people who use the drug/prevalence of drug taking;
- the number of deaths from illegal drugs;
- general acceptance or rejection of drug – takers;
- e.g. it is socially acceptable to drink alcohol;
- but not acceptable to inject heroin;
Social problems associated with heavy alcohol drinking #
- personal relationship affected/considerable stress caused to the family;
- social isolation from friends/neighbours/embarrassment;
- violence in marriage + marital breakdown;
- correlated with wife battering (half husbands involved frequently drink);
- aggressiveness + destruction of property;
- crime as means to finance drinking;
- drink-driving + traffic accidents;
- neglect of food intake;
- frequent changes of jobs/loss of employment;
- uncontrollable anger;
- sexual assault;
- grandiose behaviour;
- young single women getting pregnant;
- conflict between parents affect children;
- sexual abuse of children
- child neglect/children more likely to need child guidance/help from social services;
- children left unattended more likely to have accidents;
- poverty resulting from money spent on alcohol;
- poverty resulting from loss of job;
- poor health leading to loss of income/premature death;
- e.g. repossession of home, default on hire purchase/mortgage repayment;
Effects of heroin on the nervous system #
- heroin is an opiate/depressant;
- does not stimulate vomit and nausea centres;
- psychoactive;
- binds (with high affinity and specificity) to pain receptors on the synapses;
- mimics encephalins;
- inhibits activities of the neurones concerned with pain;
- inhibits activities of cardiac and respiratory systems;
- gives a sense of warmth/rush;
Short term effects of alcohol consumption on the brain #
- depressant;
- effects depends on blood alcohol concentration;
- depresses brain function;
- by inhibiting reticular activating system (RAS);
- therefore activity of cerebral cortex
- intellectual faculties diminished;
- loss of coordination/judgement/control over fine movement;
- e.g. slurred speech/staggering walking;
- depression of respiratory centres/death;
- relaxed feeling/increased confidence/reduced tension;
- loss of inhibitions;
- slower reaction time;
- loss of balance;
Long term consequences of alcohol consumption on the liver, brain and peripheral nervous system #
- Liver
- inflammation;
- scarring/fibrous tissue;
- cirrhosis/hepatitis/jaundice/cancer;
- fatty liver;
- compression of blood vessels in liver (blood forced from portal veins into veins from oesophagus and rectum);
- Brain
- loss of short term memory
- impaired judgement;
- confusion /disorientation/ anxiety/ hallucinations;
- impaired motor control;
- dementia;
- sleep disturbance/reduced REM sleep;
- shrinkage of brain cells;
- by alcohol induced dehydration;
- inhibits secretion of AHD so kidneys remove more water than normal ;
- hypoxia – low blood oxygen causes death of brain cells;
- low blood glucose levels cause death of brain cells
- blockage of brain capillaries;
- loss of intellectual functions e.g. calculations, learning;
- Peripheral nervous system
- (poly) neuropathy (neurological disorder that occurs when many PNS throughout the body malfunction simultaneously);
- damage to sensory nerves;
- feeling cold, pains/cramps/numbness(partial/total lack of sensation)/tingling;
- starts in hands and spread to centre of body;
- damage to motor neurones;
- muscle wasting/weakness;
- damage to autonomic nerves;
- related to faintness/incontinence (involuntary urination/defecation) / importance(powerlessness /feeble/weak) /blurred vision/ poor control of gut;
- caused by Vitamin B1/thiamine deficiency;
- poor diet/all or most energy needs from alcohol so no balanced diet;
- damage to axons;
