Hypothalamus and Posterior Pituitary

Question 1

What does the hypothalamus integrate and interpret?

Answer 1

Info from CNS, PNS and endocrine system

Question 2

What is the response from the hypothalamus?

Answer 2

Visceral ANS
Neuroendocrine function

Question 3

Where is the hypothalamus arranged?

Answer 3

Either side of 3rd ventricle

Question 4

What are the 5 main nuclei for endocrine regulation in the hypothalamus?

Answer 4

paraventricular
dorsomedial
supraoptic
ventromedial
arcuate

Question 5

What is the pituitary gland?

Answer 5

Master gland of endocrine system

Question 6

What are the 2 lobes of the pituitary gland?

Answer 6

Anterior and posterior lobe

Question 7

What two places do neuroendocrine cells in hypothalamus release hormones to?

Answer 7

Systematic circulation (posterior)
Local portal circulation that perfuses into anterior

Question 8

What are the 3 types of neuronal endocrine cells?

Answer 8

peptidergic neuroendocrine cells
magnocellular neurons
Parvocellular

Question 9

What do peptidergic neuroendocrine cells release?

Answer 9

peptide hormones into circulation

Question 10

What do magnocellular neurons release?

Answer 10

Oxytocin and ADH into systemic circulation via vasculature of posterior pituitary

Question 11

What do parvocellular neurons release?

Answer 11

TRH< CRH< SST, GHRH, GnRH, dopamine into hypophyseal portal circulation

Question 12

What are hypophysiotrophic hormones?

Answer 12

Hormones that regulate hormone production in anterior lobe of pituitary gland

Question 13

What is Kallman’s Syndrome?

Answer 13

Inherited disorder of GnRH deficiency
KAL1 gene mutations

Question 14

What are 4 characteristics of Kallman’s Syndrome?

Answer 14

Hypogonadotrophic hypogonadism
Infertility
Absent/partial pubertal maturation
Anosmia

Question 15

What are the 4 regions of the posterior pituitary?

Answer 15

Pars tuberalis
Pars distalis
Pars intermedia
Pars nervosa

Question 16

What are 3 features of the neurohypophysis?

Answer 16

Unmyelinated nerve axons
Pituicytes (glial cells)
Herring bodies - secretory granules

Question 17

What is vasopressin secreted by?

Answer 17

Neurons whose cell bodies originate in SON and PVN of hypothalamus with axons that terminate in posterior pituitary

Question 18

What 2 receptors does vasopressin act through?

Answer 18

V1 in vascular smmoth muscle cells
V2 in renal tubule epithelial cells

Question 19

What does vasopressin play a role in?

Answer 19

Osmoregulation - promotes H2O retention by stimulating renal H2O reabsorption

Question 20

What 3 stimuli control vasopressin/ADH release?

Answer 20

Blood osmolality
Hypovolemia
HYpotension

Question 21

What is a disease related to vasopressin/ADh deficiency?

Answer 21

Diabetes Insipidus - excretion of large volumes of dilute urine, dehydration and inability to reabsorb water

Question 22

What are two types of diabetes insipidus?

Answer 22

Neural - hypothalamus/pituitary lesion
Nephrogenic DI - renal resistance to vasopressin/ADH

Question 23

How is DI treated?

Answer 23

Desmopressin

Question 24

What is SIADH?

Answer 24

Inappropriate ADH secretion despite normal or increased plasma volume by pulmonary and GIT tumours

Question 25

What is oxytocin secreted by?

Answer 25

Peptidergic neuroendocrine cells in PVN and SON

Question 26

What are 3 physiological roles of Oxytocin?

Answer 26

Parturition
Lactation
Social/mating/emotional behaviour
Weak antidiuretic action

Question 27

How does oxytocin stimulate lactation?

Answer 27

Stimulates myoepithelial contractions to expel milk from mammary alveoli into ducts/collecting chamber

Question 28

What role does oxytocin have in parturition?

Answer 28

Stimulates uterine contractions
Can be used to induce labour

Question 29

Why is oxytocin nicknamed the ‘cuddle chemical’?

Answer 29

Post coital ‘glow’ - promotes monogamy
Postpartum mother child bonding
Reduces fear and anxiety
Promotes trust and empathy