Pituitary

Question 1

Where is the pituitary gland?

Answer 1

Between and behind eyes
Deep in the brain

Like two grapes hanging off the hypothalamus

Question 2

Describe the structure of the pituitary?

Answer 2

Attached to hypothalamus via the infundibulum (stalk)

Two ‘lobes’ anterior and posterior

Question 3

What is a hypophysis?

Answer 3

Another name for pituitary gland

Question 4

Blood supply of pituitary?

Answer 4

Posterior pituitary receieves blood from many arteries

Anterior pituitary receives blood from a portal vein from the hypothalamus

Question 5

What is the name of the portal venous system that supplies the anterior pituitary?

Answer 5

Hypothalamo-hypophysial portal system

Question 6

What does the pituitary do?

Answer 6

Produces different hormones which regulate the function of all the endocrine glands

Question 7

List some effects that hormones made by the pituitary have on the body?

Answer 7

Growth
Thyroid function
Puberty
Steroid production in body

Question 8

What control pituitary function?

Answer 8

Hypothalamus

Question 9

How does the hypothalamus communicate with the anterior pituitary gland?

Answer 9

Hypothalamus secretes a hormone into the hypothalamo-hypophysial portal system

It goes to the anterior pituitary, stimulating the pituitary to release hormones

Question 10

Which hormones are produced in the anterior pituitary? What are the target organs for these hormones?

Answer 10

Growth hormone: bones + soft tissues

Adrenocorticotropic hormone (ACTH): adrenals

Thyroid stimulating hormone: thyroid

FSH and LH: ovaries and testes

Prolactin: breast

Question 11

Which hormones does the posterior pituitary gland make?

What are the target organs for these hormones?

Answer 11

Anti-diuretic hormone: kidney

Oxytocin: breast, uterus in labour

Question 12

How does the hypothalamus communicate with the posterior pituitary gland?

Answer 12

Neuronal communication

Question 13

Name some diseases of the pituitary?

Answer 13

Benign adenoma
Craniopharyngioma
Trauma
Apoplexy / Sheehan's
Sarcoid / TB

Question 14

What problems does benign adenoma of pituitary cause?

Answer 14

Pressure on local structures: optic chiasm, dura

Raised ICP

Pituitary hormone production problems (deficiency or excess)

Question 15

What is a craniopharyngioma?

Answer 15

Childhood tumour affecting the hypothalamus and pituitary

Question 16

Clinical features of craniopharyngioma?

Answer 16

Raised ICP

Visual problems

Pituitary hormone deficiency

Question 17

What visual problems occur when a pituitary tumour presses on the optic chiasm?

Answer 17

Bilateral hemianopia

Question 18

What happens when a pituitary tumour presses on the dura?

Answer 18

Headaches

Question 19

What happens when a pituitary tumour causes deficiency of pituitary hormones?

Answer 19

Hypopituitarism

Question 20

Clinical features of hypopituitarism?

Answer 20

Pale
Central obesity
Lack of body hair

Amenorrhoea in women

Question 21

What are functioning pituitary tumours?

Answer 21

Tumours of pituitary that cause it to release excess of the normal hormones it produces

Question 22

Name the big 3 conditions caused by functioning pituitary tumour?

Answer 22

Prolactinomas

Acromegaly

Cushing’s syndrome

Question 23

Difference between microadenoma and macroadenoma?

Answer 23

Micro = less than 1cm
Macro = more than 1cm

Question 24

You suspect a patient has a problem with the hypothalamus-pituitary-thyroid axis.

How do you investigate?

Answer 24

Measures levels of

TSH
T3 and T4

Question 25

What levels of TSH, T3 and T4 would you expect to see in primary hypothyroidism?

Answer 25

Low T3, T4 High TSH Thyroid is not working so low T3 and T4 Pituitary tries to compensate so releases more TSH

Question 26

What levels of TSH, T3 and T4 would you expect to see in hypopituitarism?

Answer 26

Low T3, T4 Low TSH Pituitary is not producing enough TSH So it is not stimulating thyroid to make T3 and T4

Question 27

What levels of TSH, T3 and T4 would you expect to see in Grave's disease?

Answer 27

High T3, T4 Low TSH Thyroid is overactive so too much T3 and T4 produced Pituitary senses high levels so releases less TSH to try to compensate

Question 28

What is a TSHoma?

Answer 28

A tumour of the pituitary that releases too much TSH

Question 29

What levels of TSH, T3 and T4 would you expect to see in THSoma?

Answer 29

High T3, T4 High TSH Tumour causes excess TSH Which stimulates more T3 and T4 production

Question 30

You suspect a patient has a problem with HIS hypothalamus-pituitary-gonadal axis. How do you investigate?

Answer 30

Measure levels of Testosterone (T) FSH and LH

Question 31

What levels of T, FSH and LH would you expect to see in primary hypogonadism?

Answer 31

Low T High FSH and LH Problem with gonads (testes) so reduced production of T Pituitary tries to compensate by producing more FSH and LH

Question 32

What levels of T, FSH and LH would you expect to see in hypopituitary?

Answer 32

Low T Low FSH and LH Pituitary is not releasing enough FSH and LH So gonads are not being stimulated to make T

Question 33

What levels of T, FSH and LH would you expect to see in excessive anabolic steroid use?

Answer 33

Low T Low FSH and LH Anabolic steroids disrupt this pathway

Question 34

You suspect a patient has a problem with HER hypothalamus-pituitary-gonadal axis. How do you investigate?

Answer 34

Measure levels of Oestradiol (O) FSH and LH

Question 35

What levels of O, FSH and LH would you expect to see in primary ovarian failure?

Answer 35

Low O High FSH and LH Dysfunctioning of ovary means no O production Pituitary tries to compensate so more FSH and LH

Question 36

You suspect a patient has a problem with their hypothalamus-pituitary-adrenal axis. How do you investigate?

Answer 36

Measure cortisol levels Synacthen test: give them a synthetic version of ACTH If healthy, cortisol levels should rise as the ACTH is triggering the adrenals to make cortisol

Question 37

What result would you see when doing a synacthen test on someone with primary adrenal deficiency?

Answer 37

Poor problem is in adrenals, no amount of extra ACTH makes the adrenals work better to make more cortisol

Question 38

What result would you see when doing a synacthen test on someone with hypopituitarism?

Answer 38

Increase in cortisol level, because the person is deficient in ACTH. If you replace the ACTH the adrenals will be stimulated to produce cortisol

Question 39

What does ACTH stand for?

Answer 39

AdrenoCortioTropic hormone

Question 40

What controls prolactin secretion?

Answer 40

Dopamine! | Not the hypothalamus

Question 41

How would you investigate problems with prolactin axis?

Answer 41

Measure prolactin levels: Prolactin is a stress hormone, more is released in times of stress Cannulate the patient (cause stress) and then measure prolactin levels for an hour after. You should see prolactin levels fall