Disruptions to homeostasis Flashcards
What is diabetes mellitus?
- Occurs when a person has abnormally high blood glucose levels
- Called hyperglycaemia
- A diabetic person either does not produce enough insulin, or their body cells have an abnormal resistance to the effects of insulin
What is diabetes type 1?
- An autoimmune disease
- Occurs when a fault in a patient’s immune system causes the destruction of the beta cells in the islet of Langerhans of the pancreases which secrete insulin
- Therefore, a person does not produce enough insulin
How is type 1 diabetes managed?
By giving the person insulin injections
Method of treatment with insulin
- Cannot be taken in tablet form as it is digested in the alimentary canal
- The only treatment is regular injections from a programmable pump which provides a continuous supply of insulin under the skin
- There is no cure
- Must have regular injections to stay alive
Long-term effects of type 1 diabetes
- Kidney failure
- Heart attack
- Stroke
- Amputations
- Blindness
- Nerve damage
What is type 2 diabetes?
- usually occurs in people over the age of 45
- patients are able to produce insulin, although their cells do not respond to it
Why is diabetes considered a lifestyle disease?
- more common in people who are not physically active and are overweight or obese
- factors include:
o lack of physical activity
o being overweight or obese
o a diet that is regularly high in fat, sugar and salt, and low in fibre
o high blood pressure
o high blood cholesterol
o smoking
Symptoms of type 2
- develops gradually, and often there are no symptoms
- estimated that half of the Australian’s who have type 2 have not yet been diagnosed
Is there a cure for type 2?
There is no cure, although it is better to be diagnosed earlier so that prevention and management methods can be put in place
Long-term effects of type 2 diabetes (if left untreated)
- heart disease
- stroke
- kidney disease
- eye problems
- nerve damage
- skin and foot problems
Management of type 2 diabetes
- maintain a healthy weight
- monitoring blood glucose
- medication
The thyroid gland
Secretes thyroxine (T4) and tri-iodothyronine (T3) to regulate metabolic rate
Important in maintaining long-term homeostasis of body temperature
Imbalances of thyroxine can be due to an imbalance in TSH
Hyperthyroidism
Too much thyroxine is produced
Most common form of hyperthyroidism
Graves’ disease
What is Graves’ disease?
- an enlargement of the thyroid gland caused by an immune system reaction
- it is not inherited, but there may be a genetic predisposition to the condition
Symptoms of hyperthyroidism
- rapid heart rate
- weight loss
- increased appetite
- fatigue
- sweating
- anxiety
- For Graves’ disease: protruding eyeballs (exophthalmia)
Treatment of hyperthyroidism
- Drugs that block the thyroid glands use of iodine
- Surgery to remove some or all of the gland
- Give a patient a drink containing radioactive iodine
What is the purpose of drinking radioactive iodine?
- The molecules are taken up by the thyroid cells
- Destroyed by the radioactivity
- Cells elsewhere in the body do not absorb iodine and are unaffected
- Eventually excreted in urine
What is hypothyroidism?
too little thyroxine is produced
more common than hyperthyroidism
Symptoms of hypothyroidism
- Slow heart rate
- Unexplained weight gain
- Fatigue or feeling a lack of energy
- Intolerance to cold
- Swelling of the face and goitre
Iodine in thyroxine and tri-iodothyronine
Thyroxine molecule – contains four iodine atoms (T4)
Tri-iodothyronine – contains three iodine atoms (T3)
What does a deficiency in iodine cause?
It prevents the thyroid gland from making enough hormones
Why does the thyroid gland become large?
The thyroid gland may then become large in an effort to increase hormone production
What is a goitre
An enlargement of the thyroid gland
Iodine deficiency
- May people suffer from it without it being severe enough to produce a visible goitre
- 46% of Australians are affected
- There is now a compulsory addition of iodine into most breads
- Iodised salt
Cretinism
- Deficiency of iodine in a pregnant mother’s diet affects the development of the baby’s brain and also retards physical development
- In severe cases the baby has severely retarded mental and physical growth or impaired movement or hearing
Hashimoto’s disease
- Most common cause of hypothyroidism
- An attack on the thyroid gland by the patient’s immune system
Surgery for the cancer of the thyroid
- May involve the removal of all or a large part of the gland
- Can cause hypothyroidism
treatment for lack of iodine causing hypothyroidism
Addition of iodine into the diet
Treatment for other causes
- Tablets containing thyroid hormones
- There is no cure
- Must be taken for the rest of a person’s life
- Must be carefully monitored as the tablets could result in hyper/hypothyroidism
Human growth hormone deficiency
Essential for normal growth and metabolism
Deficiency of hGH leads to growth retardation (dwarfism) which is an inheritable or acquired disease
Treatment
- Injections of growth hormone
- Made by genetically engineered E. coli bacteria
- Unlimited supply of this hormone
- Can also be used to enhance athletic performance and in anti-ageing treatments
