Human Development

Question 1

What are the four general functions of hormones?

Answer 1

• Stimulate cell function
• Inhibit cell function
• Maintain a physiological state
• Stimulate or inhibit cell growth or differentiation

Question 2

What organ produces TSH?

Answer 2

Anterior pituitary

Question 3

What specialised cells produce TSH?

Answer 3

Thyrotrophs in the anterior pituitary

Question 4

What organ produces TRH?

Answer 4

Hypothalamus

Question 5

Describe the thyroid axis:

Answer 5

1) The hypothalamus releases TRH
2) The anterior pituitary releases TSH
3) The thyroid glad releases T3 and T4
4) T3 and T4 travel to organs and affect basal metabolic rate and pulse
5) High levels of T3 and T4 feeds back to the hypothalamus and the anterior pituitary to halt TRH and TSH production respectively.

Question 6

What kinds of hormone are TRH, TSH, T4 and T3?

Answer 6

TRH = releasing factor
TSH = trophic hormone
T3 and T4 = target hormone

Question 7

What causes hypothyroidism?

Answer 7

A deficiency at any point within the thyroid axis.

Question 8

What is tertiary deficiency in hypothyroidism?

Answer 8

A problem with the hypothalamus and TRH

Question 9

What is secondary deficiency in hypothyroidism?

Answer 9

A problem with the anterior pituitary and TSH

Question 10

What is primary deficiency in hypothyroidism?

Answer 10

A problem with the thyroid gland itself and T3/T4

Question 11

What is peripheral resistance in hypothyroidism?

Answer 11

Where the target tissues do not recognise T3/T4 circulating in the blood.

Question 12

What is the most common form of hypothyroidism?

Answer 12

Primary

Question 13

What is an example of incidental hypothyroidism?

Answer 13

When patients go to ophthalmologists for vision problems and it turns out to be caused by a pituitary mass pressing down on the optic chiasm.

Question 14

Where does the pituitary gland lie in the skull?

Answer 14

In the sella turcica

Question 15

What is severe bi-temporal haemianopia?

Answer 15

Partial blindness where the vision is completely gone from the outer half of both eyes.

Question 16

What are the hormones released by the anterior pituitary?

Answer 16

TSH
ACTH
GH
LH/FSH
PRL

Question 17

What are the signs and symptoms of hypothyroidism?

Answer 17

• Weight gain
• Lethargy
• Low mood
• Cold intolerance
• Dry, cold, yellowish skin
• Non-pitting oedema
• Dry, coarse scalp hair, loss of lateral aspect of eyebrows
• Hoarse voice
• Decrease in memory/cognition
• Constipation
• Menorrhagia
• Decreased deep tendon reflexes
• Carpal tunnel syndrome
• Goitre
• Weakness/myalgia

Question 18

What changes in hormones occur in an almost complete anterior pituitary failure?

Answer 18

• Slightly increased prolactin
• Decreased growth hormone and cortisol response to hypoglycaemia
• Decreased testosterone
• Normal thyroxine

Question 19

How do you test for TSH levels?

Answer 19

By checking T3/T4 levels

Question 20

How do you test for LH levels?

Answer 20

By checking testosterone and oestradiol levels

Question 21

How do you test for FSH levels?

Answer 21

Spermatogenesis

Folliculogenesis

Question 22

How do you test for GH levels?

Answer 22

IGF-1 (insulin-like growth factor 1) - do an insulin tolerance test (ITT)

Question 23

How do you test for ACTH levels?

Answer 23

Measure cortisol levels by a synacthen test

Question 24

What is an insulin tolerance test?

Answer 24

Insulin is injected and blood glucose levels are measured at regular intervals.

Question 25

What is an adequate cortisol response to an ITT?

Answer 25

A rise in cortisol to greater than 550nmol/L

Question 26

What is an adequate GH response to an ITT?

Answer 26

GH levels exceeding 20mU/L

Question 27

How do you determine the level of the endocrine axis/hierarchy that is abnormal?

Answer 27

By measuring the function of each level in turn.

Question 28

What are the 5 steps of a general endocrine evalutation?

Answer 28

1) Assess clinical symptoms
2) Determine what hormone is causing the symptoms
3) Determine the level of the endocrine axis
4) Localise the site of the abnormality
5) Identify the pathology

Question 29

if T4 is low, but TSH is high, then it is _______ _______________.

Answer 29

Primary hypothyroidism

Question 30

If T4 is low and TSH is low, then it is ______________.

Answer 30

Hypopituitary

Question 31

How is prolactin secreted?

Answer 31

Dopamine (which inhibits pituitary lactotrophs) is no longer released or recognised allowing prolactin to be secreted.

Question 32

What is the size difference between microadenoma and macroadenoma?

Answer 32

Greater or smaller than 10mm

Question 33

What does excess GH secretion cause?

Answer 33

Acromegaly - enlargement of hands and feet

Question 34

What does excess ACTH secretion cause?

Answer 34

Cushing’s syndrome

Question 35

What does excess PRL secretion cause?

Answer 35

Galactorrhoea (abnormal lactation) and amenorrhoea (absence of menstruation)

Question 36

What does excess TSH secretion cause?

Answer 36

Thyrotoxicosis

Question 37

How do you determine if a macroadenoma is functioning?

Answer 37

You stain for particular cell groups.

Question 38

The surgery to remove a pituitary tumour is called ____________________ surgery.

Answer 38

Trans-sphenoidal

Question 39

What are the four ways a pituitary tumour can be treated?

Answer 39

1) Conservative/surveillance (when the tumour is non-functioning and not very large)
2) Surgery
3) Medical (for prolactin-secreting tumours)
4) Radiotherapy (as a second-line treatment)

Question 40

How do you medically treat a prolactin-secreting hormone?

Answer 40

By giving a drug that mimics dopamine which inhibits prolactin secretion and shrinks the tumour.

Question 41

How do you treat hypopituitarism?

Answer 41

By replacing the un-secreted hormones.

Question 42

What must be particularly paid attention to when treating hypopituitarism?

Answer 42

Ensuring that the hormone replacement mimics the diurnal variation and the evolution of hormone levels over time.