HPA axis

Question 1

Name 6 general pituitary functions

Answer 1

Feeding
Stress response
Water balance
Sleep-wake cycle
Thermoregulation
Emotions

Question 2

Where does the pituitary gland sit

Answer 2

Sella turcica which is a small depression in sphenoid (pituitary fossa)

Question 3

What are the proper names for anterior/ posterior pituitary

Answer 3

Anterior= adenohypophysis
Posterior= neurohypophysis

Question 4

Where is the anterior lobe of pituitary derived from

Answer 4

Upward migration from roof of the mouth called Rathke’s pouch
Composed of glandular secretory epithelial tissue

Question 5

Where is the posterior lobe of pituitary derived from

Answer 5

Downward migration of neuroectoderm from the diencephalon directly connected to hypothalamus

Question 6

Do the anterior and posterior lobes share the same venous drainage

Answer 6

Yes

Question 7

Where does the anterior pituitary gland receive supply from

Answer 7

Superior hypophyseal artery

Question 8

What is the hypothalamo-hypophysial portal system

Answer 8

Superior hypophyseal artery forms a capillary network around the hypothalamus and blood from this network is transported to secondary capilary plexus surrounding anterior pituitary

Question 9

What artery supplies the posterior pituitary

Answer 9

Blood supply from inferior hypophyseal artery

Question 10

Where does pituitary blood supply drain

Answer 10

Into efferent anterior and posterior hypophyseal portal veins
Drains into cavernous sinus

Question 11

Briefly state what is meant by the HPA axis

Answer 11

• Stimulus causes hypothalamus to secrete a hormone
• This causes pituitary to secrete another hormone
• Act on a target organ which may or may not secrete another hormone

Question 12

Name 4 stimuli for the thyroid axis

Answer 12

Cold, acute psychosis, severe stress, circadian rhythm

Question 13

What does the hypothalamus release in response to thyroid axis stimuli?

Answer 13

Thyrotropic releasing hormone

Question 14

What inhibits release of TRH

Answer 14

• T4 levels

- Somatostatin, dopamine, corticosteroids

Question 15

What does the pituitary release in response to TRH

Answer 15

TSH

Question 16

What inhibits TSH release

Answer 16

T3

Question 17

What does the thyroid gland release in response to TSH

Answer 17

T4 and T3

Question 18

What are the stimuli for growth hormone release

Answer 18

Circadian rhythm, stress, hypoglycaemia, ghrelin

Question 19

What stimulates the pituitary gland to release growth hormone

Answer 19

Growth hormone releasing hormone

Question 20

What does growth hormone stimulate? Effect of this?

Answer 20

Stimulates IGF-1 release from the liver

Growth

Question 21

What inhibits GHRH release

Answer 21

IGF-1

GH

Question 22

Whst inhibits growth hormone release

Answer 22

GH
Somatostatin
IGF-1

Question 23

Role of growth hormone?

Answer 23

Stimulates growth and repair
Regulates carbohydrate metabolism
Effects cell proliferation

Question 24

What can growth hormone deficiency cause

Answer 24

Inadequate energy and impaired well being
Role in insulin resistance and lipid metabolism and thus deficiency can cause hyperlipidaemia
Decreased bone mineral density
Impaired cardiac function

Question 25

What is CRH

Answer 25

Corticotropin releasing hormone

Question 26

What stimulates release of CRH

Answer 26

Circadian rhythm, stress and hypoglycaemia | ADH

Question 27

What stimulates the pituitary gland to release adrenocorticotropic hormone

Answer 27

- CRH | - ADH

Question 28

What is the effect of ACTH release

Answer 28

Cortisol release from zona fascilculata of the adrenal gland

Question 29

What does cortisol inhibit release of

Answer 29

adh acth crh

Question 30

Effect on the body of cortisol release

Answer 30

- Gluconeogenesis and glycogenolysis - Suppreses immune system - Aids in fat, protein and carbohydrate metabolism

Question 31

When does cortisol release peak

Answer 31

Just after waking up

Question 32

What is cushings?

Answer 32

Excess cortisol

Question 33

What is the difference between cushings syndrome cushings disease

Answer 33

``` Syndrome= ACTH independent= adrenal hyperplasia or adrenal adenoma Disease= ACTH dependent= pituitary adenoma ```

Question 34

What is addisons

Answer 34

Low cortisol

Question 35

What stimulates the hypothalamus tol release GnRH

Answer 35

Kisspeptin

Question 36

What is released from the pituitary when GnRH is released

Answer 36

LH and FSH

Question 37

What inhibits kisspeptin

Answer 37

Prolactin

Question 38

What inhibts GnRH release

Answer 38

Oestrogen | Testosterone

Question 39

What inhibits LH and FSH

Answer 39

Oestrogen | Testosterone

Question 40

What stimulates prolactin release

Answer 40

Nipple sucking

Question 41

What does prolactin release from the hypothalamus cause the pituitary to release

Answer 41

Prolactin

Question 42

What inhibits prolactin release

Answer 42

Dopamine

Question 43

What is the difference between primary and secondary hormone underactivity

Answer 43

``` Primary= underactivity at target organ Secondary= underactivity at pituitary ```

Question 44

Where is ADH released from

Answer 44

Neurons from supraoptic nuclei

Question 45

Where is oxytocin released from

Answer 45

Neurons from paraventricular nuclei

Question 46

Effect of oxytocin

Answer 46

Affects uterine contraction in pregnancy and birth | Stimulates initial release of breast milk post birth

Question 47

What is the most and least vulnerable hormone to be lost because of a pituitary tumour

Answer 47

Growth hormones- most# | ACTH- last to be lost

Question 48

What is an addisonian crisis

Answer 48

Rapid drop in ACTH leading to hypovolemic shock, vascular collapse, profound electrolyte abnormalities, confusion and psychosis