Loss of Homeostasis

Question 1

Growth hormone disorders

Answer 1

Excess of GH, hypersecretion = gigantism
Deficiency of GH, hyposecretion = dwarfism

Question 2

How does infantile hypothyroidism occur?

Answer 2

Not enough thyroid hormone in newborns leads to low metabolic rate, cold intolerant, stumped growth, inhibited brain developement
Caused by lack of iodine in mothers diet

Question 3

What happens when you are iodine deficient?

Answer 3

Thyroid gland unable to make TH
Stored TH is depleted, TRH and TSH secretion increase to stimulate thyroid glands to make more TH
Without iodine TH cannot be made resulting in overstimulation of thyroid gland and growth of thyroid gland

Question 4

What is graves’ disease?

Answer 4

Occurs when too much thyroid hormone is secreted (hypersecretion)
Symptoms : high metabolic rate and weight loss
Cause : autoimmune disorder

Question 5

What is hyperparathyroidism?

Answer 5

Excess in PTH secretion caused by parathyroid tumour
Bones become soft, deformed and fragile
Raise blood levels of calcium and phosphate ions promoting formation of kidney stones

Question 6

What is hypercalcaemia?

Answer 6

[Ca2+] in blood is too high
Nerve and muscle cells less responsive and excitable
Can lead to depression of nervous system and muscle weakness
Caused by tumours and other factors

Question 7

What is hypocalcaemia?

Answer 7

[Ca2+] in blood is too low
Increased excitability of nervous system
Leads to muscle tremors, spasms or cramps
Caused by tumours, Vit D deficiency etc.

Question 8

What is type 1 diabetes mellitus?

Answer 8

Hyposecretion : too little or no insulin secreted
Caused : destruction of pancreatic beta cells
Outcome : glucosuria and polyuria
Treatment : insulin injections or infusion

Question 9

What is type 2 diabetes mellitus?

Answer 9

Hyposensitive : too little or no response to insulin
Caused : desensitisation of insulin receptor, associated with obesity
Outcome : glucosuria and polyuria
Treatment : changes in diet and exercise, medication

Question 10

How is diabetes mellitus diagnosed?

Answer 10

Need to check response to glucose, insulin levels and long term exposure

Question 11

What is glucagon?

Answer 11

Primary action is to increase blood glucose
Problems with glucagon signalling can be recused through action of other hormones - GH, adrenaline and cortisol