MINDARIE SENIOR COLLEGE

1. MINDARIE SENIOR COLLEGE 3A/3B Human Biological Science Homeostatic Dysfunction

2. Hormonal causes of disruptions: Diabetes mellitus • Symptom: • Hyperglycaemia: abnormally high levels of blood glucose. • Role of insulin: • Stimulate cells to take in glucose from blood. • Stimulate conversion of glucose into glycogen by liver and muscle cells. • Dysfunction: • Insufficient insulin production or cells resistant to insulin effects. • High levels of blood glucose. • Large quantities of glucose excreted in urine. • Types: • Type 1 (insulin dependent diabetes). • Type 2 (non-insulin dependent or adult onset diabetes).

3. Type 1(insulin dependent or juvenile diabetes ). • Cause: • Fault in immune system causes destruction of beta cells in Islets of Langerhans. • No insulin produced. • Treatment: • Tablets not suitable as insulin is digestible. • Regular injections of insulin • Programmable insulin pump • No cure • Long Term Effects: • Kidney failure • Heart attack • Stroke • Amputations • Blindness • Nerve damage

4. Type 2(non-insulin dependent or adult onset diabetes). • Cause: • Insulin is produced but cells do not respond to it. • Lifestyle disease. • Risk factors: • Inactivity • Obesity • Energy rich/low fibre diet • Hypertension • High blood cholesterol • Smoking • Treatment: • Often no symptoms – and not diagnosed. • Preventable by adopting a healthy lifestyle. • No cure • Early diagnosis can lead to successful management. • Long Term Effects: • Heart disease • stroke • Kidney disease • Eye problems • Nerve damage • Skin and foot problems.

5. Hormonal causes of disruptions: Excess or deficiency of thyroid hormones. • Symptom: • Too little or too much thyroid hormones (thyroxine and tri-iodothyronine) • Role of thyroxine and tri-iodothyronine: • Stimulate carbohydrate, protein and fat metabolism. • Regulate basal metabolic rate. • Influence long term homeostasis of body temperature • Dysfunction: • Imbalance in Thyroid Stimulating Hormone from anterior Pituitary leads to imbalance in thyroxine. • Large quantities of glucose excreted in urine. • Types of dysfunction: • Hyperthyroidism • Hypothyroidism

6. Hyperthyroidism • Cause: • Too much thyroid hormone secreted. • Types: • Graves’ disease (most common form) • Enlarged thyroid caused by immune system reaction. • Genetic predisposition. • Effects: • Overstimulation of cells • restlessness • Rapid heart rate • Weight loss • Increased appetite • Anxiety/excitable • Fatigue • Sweating • Swings in mood and emotional state. • Protruding eye balls – exophthalmia - (Graves’ disease) • (Pres G W H Bush suffered this condition.) • Treatment: • Drugs to block thyroid gland’s use of iodine. • Surgery to remove all or part of thyroid gland • Radioactive iodine used to over active thyroid cells.

7. Hypothyroidism • Cause: • Too little thyroid hormone secreted. • Problems with hypothalamus, pituitary gland or thyroid gland. • More common of the two conditions (6%-10% Australian females suffer) • Lack of iodine in diet prevents thyroid secreting sufficient hormones. • Surgical removal (cancer treatment) of gland or parts of gland. • Effects: • Goitre • Thyroid gland becomes enlarged in attempt to produce more hormone. • Cretinism • Deficiency of iodine in maternal diet • Baby severely mentally and physically retarded, impaired movement and hearing. • Hashimoto’s disease • Immune system attacks thyroid gland • Treatment: • Inclusion of extra iodine in diet (if this is the cause) • No cure. • Carefully monitored doses of thyroid hormone (tablets)

8. Behavioural causes of homeostatic disruption • Drugs • Non-medicinal drugs may interfere with nerve impulse transmission by binding to receptor sites. • Caffeine • Effects • Stimulates metabolism and CNS • Increases heart rate • Increases kidney blood flow, increasing urine production. • Increases pulmonary blood flow and relaxes bronchioles, increasing pulmonary ventilation. • Alcohol • Effects • CNS depressant • Stimulates insulin secretion, lowering blood sugar levels. • Inhibits secretion of ADH, increasing urine output and dehydration

9. More behavioural causes of homeostatic disruption • Drugs (continued) • Amphetamine and methamphetamine • Effects • Cause release of noradrenaline, dopamine (hormones and neurotransmitters) and serotonin (neurotransmitter) • May enhance alertness, motivation and clear thinking • Disrupts homeostasis by affecting appetite and weight control • MDMA (ecstacy) • Synthetic amphetamine • Effects • Cause release of noradrenaline, dopamine and accumulation of serotonin. • Initiates fight or flight syndrome, user feels more energetic • Increase heart rate and blood pressure • Increases breathing rate • Causes sweating and dehydration • Decreases appetite • In high doses – rapid rise in body temp and BP, heart palpitations, vomiting.

10. More behavioural causes of homeostatic disruption • Drugs (continued) • Cocaine • Effects • Blocks removal of noradrenaline, dopamine and serotonin from synapse between nerve cells • Stimulates CNS • Disrupts homeostasis by increasing heart rate, blood pressure, body temperature, breathing rate, dilating pupils, loss of appetite. • Heroin • Effects • Used medicinally as strong analgesic. • When injected recreationally, binds to brain receptors resulting in • Intense euphoria • Decrease in pain perception • Relief from anxiety. • Profound effects on homeostasis • Depresses control of breathing • Depressed control of blood pressure and body temperature • Irregular heart rate • Unconsciousness, coma or death (large dose)

11. More behavioural causes of homeostatic disruption • Excessive activity • Well planned, monitored and not obsessively over taxing exercise levels are beneficial • Excessive activity may cause physical damage to tendons, muscles, ligaments, cartilages, bones and joints. • Homeostatic dysfunction may result • If nutrition is inadequate muscle may breakdown to source energy • Eating disorders are strongly linked to excessive exercise. • Great stress on heart may lead to cardiovascular problems • Loss of Calcium deposition may lead to osteoporosis. • Amenorrhoea may occur if energy uptake is inadequate.

12. More behavioural causes of homeostatic disruption • Eating habits • Deficiency diseases may result from inadequate intake of vitamins and minerals • Examples of deficiency: • Iodine • Iron • Causes anaemia: • insufficient haemoglobin • Reduced oxygen carrying capacity of RBC’s • Reduced rate of Cellular Respiration and energy release. • causing weakness, fatigue, breathlessness, elevated heart rate. • Vitamin B • causes Pernicious anaemia (stem cell divisions don’t occur) • Vitamin K • Produced by bacteria in large intestine. • Lack causes reduced blood clotting ability. • Homeostasis compromised if excessive blood is lost. • Energy balance (intake and use) is a complex but essential element of homeostasis. • Alimentary canal, hormones, CNS (hypothalamus), Autonomic NS are linked. • Imbalances may be caused physically or psychologically. • Lifestyle, eating habits and natural selection play a role in contributing to obesity epidemic

13. Homeostatic disruption caused by disease. • A disease is any condition in which normal functioning is impaired. • Some diseases have direct effects on homeostasis • Emphysema: • Alveolar walls breakdown, reducing surface area for gas exchange • results in difficulty in taking in oxygen • Cause: • Smoking • Symptoms • Breathlessness, initially during activity, and eventually, constantly • Treatment: • damage is irreversible • Fever: • An elevation of body temperature • A symptom of a disease • Cause: • Many infections. • Symptoms • 1 or 2 degrees C increase in core temperature. • Effect: • Helps immune system overcome infection • Disrupts homeostasis by affecting many body reactions - increasing temp beyond optimal range.

14. More homeostatic disruption caused by disease. • Hypertension: • Cause: • Homeostatic mechanisms unable to keep blood pressure within normal range • Genetic factors, • excessive salt intake • obesity • Inactivity • High alcohol intake • Kidney disease • Poor lifestyle choices • Effects • Significant risk factor for cardiovascular disease and kidney failure • Treatment: • Adopt a healthy lifestyle • Injuries: • Examples: • Excessive blood loss limits supply of oxygen and glucose, and removal of carbon dioxide and wastes. • Punctured/collapsed lung impairs gas exchange • Immobility limits venous return • Spinal cord injuries reduce innervation of respiratory muscles.

15. Hormonal treatments to homeostatic disruptions • Hormone replacement therapy • To treat symptoms of menopausal women • hot flushes and night sweats • Uncomfortable skin sensations • Headaches • Thinning and dryness of walls of vagina • Aches and pains • Frequent urination • Reduced libido • Tiredness and irritability • Mood disturbances, loss of self esteem, depression • Sleeping difficulties • Treatment • May not require medical intervention • Severe symptoms may need HRT • Oestrogen and progesterone prescribed to counteract loss or irregularities in natural secretions • Carefully managed doses given as tablets, patches, gels, implants or nasal spray. • Risks and benefits must be carefully assessed • May lead to side effects – bleeding, bloating, breast tenderness, slight increase in risk of breast cancer, CV disease, thrombosis.

16. More hormonal treatments for homeostatic disruptions • Corticosteroids and treatment of rheumatoid arthritis • Rheumatoid arthritis • A crippling disease • Immune system attacks synovial membrane of joints, causing painful swelling and deformity • Treatment • Corticosteroids, closely related to cortisol (the ‘ stress hormone’ secreted by the adrenal gland) • Act on immune system to block production of substances which stimulate allergic and inflammatory responses • Side effect – reduce resistance to infection due to interference to WBC’s. • Usage of lowest possible doses must be managed verycarefully

17. Behavioural treatments for homeostatic disruptions • Control of reproduction • Intervention in Menstrual Cycle and Ovarian Cycle • Hormonal contraception • Combined Pill (synthetic progesterone and oestrogen) • Prevent ovulation • Reduce ability of sperm to enter uterus • Reduce likelihood of implantation • Mini Pill (progesterone substitute) • Thickens mucus plug in cervix preventing entry of sperm • Reliable, effective and allows personal choice. • Some risks involved with intervention to normal body functioning • Combined pill - Headaches, nausea, increased appetite, breast tenderness, increased incidence of heart attacks, strokes, blood clots • Mini Pill – fewer complications, but less reliable if not used with discipline. • Female infertility • Drugs, synthetic forms of pituitary hormones, can be used to induce ovulation • High risk of multiple pregnancy • Use of in-vitro fertilization • Side effects to hormones, multiple pregnancies, premature birth must be considered. • Male infertility • Problem with up to 50% of infertile couples due to male sperm problems • Treatment with gonadotrophins over several months may help.