Loss of homeostasis

Question 1

What is the cause and affects of hyposecretion of cortisol

Answer 1

Autoimmunity - Addison’s disease.
Leads to increase in ACTH (melanin synthesis)
Symptoms: Low blood pressure, Weakness

Question 2

What is the cause and affects of hypersecretion of cortisol

Answer 2

Tumours - Cushing’s disease.
Mobilises fat redistribution (causing humps)
Symptoms: High blood pressure, Weakness

Question 3

What is the cause and affects of excess growth hormone

Answer 3

Hypo (excess) - Gigantism

Hyper (Deficiency) - Dwarfism

Question 4

What is the cause and affects of hyposecretion of Thyroid hormone (infants)

Answer 4

Many factors can disrupt hormone signalling - Infant hypothyroidism.
Lack of iodine in mothers diet
Symptoms: Low metabolic rate, cold intolerant, growth retarded, inhibited brain development

Question 5

What is the cause and affects of hyposecretion of thyroid hormone (adults)

Answer 5

Many factors can disrupt hormone signalling - Iodine deficiency disorder (simple goitre).
Unable to make more hormone when stores depleted. TRH and TSH secretion increases to make more TH and losses negative feedback loop, thyroid enlarges.

Question 6

What is often the cause of hyposecretion of thyroid hormone

Answer 6

A lack of iodine in some ones diet.

Question 7

What is the cause and affects of hypersecretion of thyroid hormone

Answer 7

Autoimmunity - Graves’ disease.

Symptoms: Weight loss, hair loss, heath intolerant (only need to know 2)

Question 8

What is the cause and affects of hypersecretion of parathyroid hormone

Answer 8

Tumours - Hyperparathyroidism.
Excess PTH secretion. Raises blood levels of calcium and phosphate ions.
Symptoms: Promotes formation of kidney stones, Bones become soft , deformed and fragile.

Question 9

What is the cause and affects of hypersecretion of Calcium

Answer 9

Tumours - Hypercalcaemia.
Nervous tissue less responsive, depression of nervous system, emotional disturbances, muscle weakness, sluggish reflexes. If plasma levels significantly elevated - cardiac arrest

Question 10

What is the cause and affects of hyposecretion of calcium

Answer 10

Many factors can disrupt hormone signalling - Hypocalcaemia.
Increased excitability of nerves, muscle tremors, spasm or cramps. Random firing of neurons, cramps tingle/burning
Caused by: Vitamin D deficiency, diarrhoea, thyroid tumours, underactive parathyroid glands, pregnancy and lactation (As extra is needed)

Question 11

What is the cause and affects of hyposecretion of glucose

Answer 11

Type 1 diabetes (mellitus) - Too little or no insulin produced. Destruction of pancreatic B cells by immune system.
Outcome: Heart problems, Inflammation damage to nerves (neuropathy) (same as type 2)

Question 12

What is the cause and affects of hyposensitive glucose receptors

Answer 12

Type 2 diabetes (mellitus) - Too little or non responsive insulin (resistance). Desensitisation of insulin receptors,(obesity).
Outcome: Glucose urine. Excess urine production (Polyuria)
(same as type 1)

Question 13

When might you need to change your setpoint to maintain homeostasis

Answer 13

Change in altitude (oxygen carrying capacity of blood)
Change in climate (Change BMR)
Fever (temporary shift)