Loss of Homeostasis

Question 1

What are the growth hormone disorders?

Answer 1

Gigantism and dwarfism

Question 2

What causes gigantism?

Answer 2

Excess growth hormone

Question 3

What causes dwarfism?

Answer 3

A deficiency in growth hormone

Question 4

What is infantile hypothyroidism?

Answer 4

Hyposecretion of thyroid hormone caused by an external factor (other)

Question 5

What ca not enough thyroid hormone in newborns lead to?

Answer 5

Low metabolic rate, growth being retarded, cold intolerant (can’t warm up), brain development is inhibited causing mental impairments

Question 6

What can cause infantile hypothyroidism?

Answer 6

Lack of iodine in a mothers diet so maternal iodine supplementation is recommended to avoid it

Question 7

What is iodine deficiency disorder known as?

Answer 7

Simple goitre

Question 8

What happens when someone is iodine deficient?

Answer 8

The thyroid gland is unable to make enough thyroid hormone (TH). When stored TH is depleted, TRH and TSH secretion increase to stimulate the thyroid gland to make more TH. Without iodine the TH is unable to be made

Question 9

What is the net result of iodine deficiency?

Answer 9

Loss of negative feedback control and overstimulation of the thyroid gland. The excess TSH stimulates growth of the thyroid gland and so a goitre/growth may be formed

Question 10

What is graves disease?

Answer 10

Hypersecretion of thyroid hormone (too much) caused by an autoimmune disorder

Question 11

What are the symptoms of graves disease?

Answer 11

High metabolic rate, weight loss, heat intolerant, increased heart rate, nervousness, hair loss, exophthalmos (plugging out of eyes) and thyroid swelling

Question 12

What does hyperparathyroidism lead to?

Answer 12

Excess PTH secretion (hyper secretion)

Question 13

What is hyperparathyroidism caused by?

Answer 13

A parathyroid tumour

Question 14

What is the effects of hyperparathyroidism?

Answer 14

Bones become soft, deformed and fragile. Raises the blood levels of calcium and phosphate ions. Promotes formation of kidney stones composed of calcium and phosphate

Question 15

What happens when blood calcium concentration is too high?

Answer 15

Hypercalcemia

Question 16

What is effected by hypercalcemia?

Answer 16

Nerve and muscle cells

Question 17

How are nerve and muscle cells effected by hypercalcemia?

Answer 17

They become less responsive and excitable because increase in extracellular calcium ions makes the membrane potential further from the threshold

Question 18

What other effects does hypercalcemia have?

Answer 18

Can lead to depression of the nervous system, emotional disturbances, muscle weakness and sluggish reflexes

Question 19

What happens if blood calcium concentration is significantly elevated?

Answer 19

Cardiac arrest can occur

Question 20

What happens when blood calcium concentration is too low?

Answer 20

Hypocalcemia

Question 21

What is effected by hypocalcemia?

Answer 21

nervous system

Question 22

How is the nervous system effected by hypocalcemia?

Answer 22

Increased excitability because decrease in extracellular calcium ions makes the membrane potential closer to threshold

Question 23

What does increased excitability of the nervous system from hypocalcemia do?

Answer 23

Leads to muscle tremors, spasms or cramps

Question 24

What happens when blood calcium levels are very low?

Answer 24

Get paraesthesia (tingling/burning sensation) in the hands and face, muscle cramps, and in some cases the muscles of the larynx may contract tightly (laryngospasm) which can shut off air flow and cause suffocation

Question 25

What can hypocalcemia be cause by?

Answer 25

Vitamin D deficiency because the gut doesn’t absorb calcium, diarrhoea, thyroid tumors, underactive or removal of parathyroid glands, pregnancy and lactation

Question 26

What is diabetes type 1?

Answer 26

Hyposecretion (too little or no) of insulin

Question 27

What can type 1 diabetes be caused by?

Answer 27

Destruction of pancreatic beta cells by the immune system

Question 28

What is the outcome/ effects of diabetes type 1?

Answer 28

Glycosuria (glucose in the urine), polyuria (excess volume of urine production) and polydipsia (thirst)

Question 29

How is type 1 diabetes treated?

Answer 29

Insulin injections or infusion

Question 30

What is diabetes type 2?

Answer 30

Hyposensitive (too little or no response) to insulin “insulin resistance”

Question 31

What is the cause of type 2 diabetes?

Answer 31

Desensitisation of insulin receptor. Associated with obesity

Question 32

What is the outcome/effects of diabetes type 2?

Answer 32

Same as type 1- Glycosuria (glucose in the urine), polyuria (excess volume of urine production) and polydipsia (thirst)

Question 33

How is type 2 diabetes treated?

Answer 33

Changes in diet and exercise. various medications

Question 34

How is diabetes mellitus diagnosed?

Answer 34

Because blood glucose concentration fluctuates throughout the day a single blood test isn’t effective. So, responses to glucose (glucose tolerance test) are checked, insulin levels and longer term exposure (HbA1C test)

Question 35

What happens if there is a problem with glucagon secretion?

Answer 35

Because there are other hormones which can increase blood glucose concentration, if there is a problem with glucagon secretion it doesn’t cause a problem as large.

Question 36

When may the set point/normal range need to be changed to maintain homeostasis?

Answer 36

Change in altitude, shift to a location with different climate, fever

Question 37

What needs to change when altitude is changed?

Answer 37

Change in blood count for oxygen carrying capacity

Question 38

What needs to change when we move to a location with a different climate?

Answer 38

Basal metabolic rate (BMR) which is linked to the thyroid hormone

Question 39

What needs to change when we get a fever?

Answer 39

The set point for temperature needs to be shifted temporarily