Pituitary

Question 1

What are the the two hormones secretes by the posterior pituitary gland

Answer 1

Vasopressin (ADH)

Oxytocin

Question 2

What is the role and nuclei of vasopressin

Answer 2

Controls water secretion into the urine

Primarily from supraoptic nuclei

Question 3

What is the role and nuclei of oxytocin

Answer 3

Expression of milk from the glands of the breast to the nipples - promotes onset of labour

Primarily from the paraventricular nuclei

Question 4

What does caffeine and alcohol do to the control and release of vasopressin

Answer 4

Inhibitor

Less ADH secreted - water loss

Question 5

What are positive feedbacks for the control of vasopressin release

Answer 5

High osmolality
Low blood volume

Nausea
Vomiting
Stress
Exercise

More ADH secreted = higher water retention

Question 6

For osmolality is the size of the particle important

Answer 6

No

Number is important

Question 7

What does drinking rapidly do to vasopressin release

Answer 7

Supresses vasopressin release and thirst

Question 8

What happens to vasopressin release in pregnancy

Answer 8

Osmotic threshold for VP release and thirst is decreased

Question 9

Does plasma vasopressin concentrations decrease or increase with age

Answer 9

Increases

Question 10

What is the release and action of oxytocin

Answer 10

Release stimulated by milk suckling

Action
- stimulates milk let down
- stimulates contraction of myometrium (100x more potent than AVP)
- 200x less active at the V2 receptor compared to AVP

Question 11

What produces positive feedback in oxytocin action

Answer 11

Suckling

Uterine contractions

Question 12

What does the pituitary secrete hormones in response to

Answer 12

Signals from hypothalamus

Question 13

What does the anterior pituitary secrete

Answer 13

ACTH

TSH

GH

LH

FSH

Prolactin

Question 14

What is the hormone type and function of adrenocorticotrophic hormone (ACTH)

Answer 14

Polypeptide

Glucorticoid and adrenal androgen production

Question 15

What is the hormone type and function of growth hormone (GH)

Answer 15

Polypeptide

Linear growth, CHO metabolism, bone mass

Question 16

What is the hormone type and function of prolactin

Answer 16

Polypeptide

Lactation

Question 17

What connects the hypothalamus to the anterior pituitary

Answer 17

Hypothalamic-hypophyseal portal system

Question 18

What does the release of thyrotropin releasing hormone (TRH) for the hypothalamus, stimulate hormone release from the anterior pituitary

Answer 18

TSH - thyroid stimulating hormone

Question 19

What does the release of corticotropin releasing hormone (CRH) for the hypothalamus, stimulate hormone release from the anterior pituitary

Answer 19

Adrenocorticotrophic (ACTH)

Question 20

What does the release of gonadotropin releasing hormone from the hypothalamus release what hormone from the anterior pituitary

Answer 20

Follicle stimulating hormone (FSH)

Luteinising hormone (LH)

Question 21

What does the release of GH releasing hormone (GHRH) from the hypothalamus trigger the release of what hormone

Answer 21

Growth hormone (GH)

Question 22

What is the inhibatory hormone released from the hypothalamus for effect on growth hormone

Answer 22

Somatostatin

Question 23

What is the inhibitor for the release of prolactin from the anterior pituitary

Answer 23

Dopamine

Question 24

What is the only anterior pituitary hormone that does not have negative feedback

Answer 24

Prolactin

Question 25

Describe ACTH - adrenocorticotropic hormone

Answer 25

Affects adrenal size - too much = big adrenal gland Regulates glucocorticoid synthesis - stimulates cortisol release - stimulates corticosteriod release - CRH stimulates ACTH release - negative feedback of cortisol on CRH and ACTH production

Question 26

Describe growth hormone (GH)

Answer 26

Released throughout life Pulsatile Stimulates by low glucose, exercise, sleep Supressed by hyperglycaemia Effectors mediated by GH and IGF1

Question 27

What are the actions of growth hormone

Answer 27

Linear growth in children Acquisition of bone mass Stimulates - protein synthesis - lipolysis (fat breakdown) - glucose metabolism Regulation of body composition Psychological well-being

Question 28

Describe thyroid stimulating hormone (TSH)

Answer 28

Negative feedback loop between TSH and thyroxine

Question 29

Describe LH and FSH (female axis)

Answer 29

LH stimulates sex hormone secretion FSH stimulates development of follicles Absence leads to infertility and hypogonadism

Question 30

Describe prolactin

Answer 30

Synthesised in lactotrophs Regulation of PRL different to other anterior pituitary hormones Negative regulation by tonic release in inhibiting factor - dopamine

Question 31

What is the role of prolactin

Answer 31

Essential for lactation Levels increase dramatically in pregnancy and during breast-feeding Inhibits gonadal activity through central suppression of GnRH