Disruptions to homeostasis

Question 1

What is diabetes mellitus?

Answer 1

• 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

Question 2

What is diabetes type 1?

Answer 2

• 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

Question 3

How is type 1 diabetes managed?

Answer 3

By giving the person insulin injections

Question 4

Method of treatment with insulin

Answer 4

• 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

Question 5

Long-term effects of type 1 diabetes

Answer 5

• Kidney failure
• Heart attack
• Stroke
• Amputations
• Blindness
• Nerve damage

Question 6

What is type 2 diabetes?

Answer 6

• usually occurs in people over the age of 45

- patients are able to produce insulin, although their cells do not respond to it

Question 7

Why is diabetes considered a lifestyle disease?

Answer 7

• 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

Question 8

Symptoms of type 2

Answer 8

• develops gradually, and often there are no symptoms

- estimated that half of the Australian’s who have type 2 have not yet been diagnosed

Question 9

Is there a cure for type 2?

Answer 9

There is no cure, although it is better to be diagnosed earlier so that prevention and management methods can be put in place

Question 10

Long-term effects of type 2 diabetes (if left untreated)

Answer 10

• heart disease
• stroke
• kidney disease
• eye problems
• nerve damage
• skin and foot problems

Question 11

Management of type 2 diabetes

Answer 11

• maintain a healthy weight
• monitoring blood glucose
• medication

Question 12

The thyroid gland

Answer 12

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

Question 13

Hyperthyroidism

Answer 13

Too much thyroxine is produced

Question 14

Most common form of hyperthyroidism

Answer 14

Graves’ disease

Question 15

What is Graves’ disease?

Answer 15

• 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

Question 16

Symptoms of hyperthyroidism

Answer 16

• rapid heart rate
• weight loss
• increased appetite
• fatigue
• sweating
• anxiety
• For Graves’ disease: protruding eyeballs (exophthalmia)

Question 17

Treatment of hyperthyroidism

Answer 17

• 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

Question 18

What is the purpose of drinking radioactive iodine?

Answer 18

• 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

Question 19

What is hypothyroidism?

Answer 19

too little thyroxine is produced

more common than hyperthyroidism

Question 20

Symptoms of hypothyroidism

Answer 20

• Slow heart rate
• Unexplained weight gain
• Fatigue or feeling a lack of energy
• Intolerance to cold
• Swelling of the face and goitre

Question 21

Iodine in thyroxine and tri-iodothyronine

Answer 21

Thyroxine molecule – contains four iodine atoms (T4)

Tri-iodothyronine – contains three iodine atoms (T3)

Question 22

What does a deficiency in iodine cause?

Answer 22

It prevents the thyroid gland from making enough hormones

Question 23

Why does the thyroid gland become large?

Answer 23

The thyroid gland may then become large in an effort to increase hormone production

Question 24

What is a goitre

Answer 24

An enlargement of the thyroid gland

Question 25

Iodine deficiency

Answer 25

• 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

Question 26

Cretinism

Answer 26

• 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

Question 27

Hashimoto’s disease

Answer 27

• Most common cause of hypothyroidism

- An attack on the thyroid gland by the patient’s immune system

Question 28

Surgery for the cancer of the thyroid

Answer 28

• May involve the removal of all or a large part of the gland
• Can cause hypothyroidism

Question 29

treatment for lack of iodine causing hypothyroidism

Answer 29

Addition of iodine into the diet

Question 30

Treatment for other causes

Answer 30

• 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

Question 31

Human growth hormone deficiency

Answer 31

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