Pituitary physiology

Question 1

what is on the sides o pituitary

Answer 1

internal carptid arteries

Question 2

what is above the pituitary

Answer 2

optic chiasm

Question 3

below pituitary

Answer 3

sphenoid sinus

Question 4

where is adh secreted from

Answer 4

posterior pituitary

Question 5

where are most hormones secretd from

Answer 5

anterior pituitary

Question 6

how are most hormones released

Answer 6

by an activating pathway
except for prolactin

Question 7

how is prolactin inhibited

Answer 7

under tonic inhibition by hypothalamic dopamine

Question 8

when do prolcatin levels rise

Answer 8

in pregnancy response to prolactin releasing hormone from hypothalamus

Question 9

dynamic endocrine testing

Answer 9

○ Hormone excess - suppression test
Hormone deficiency - stimulation test

Question 10

stimulatory tests

Answer 10

synacthen test
diagnostic procedure used to assess the function of adrenal glands and their response to ACTH

Question 11

key components of synacthen test

Answer 11

synthetic form of ACTH
stimulates adrenal glands to produce cortisol

cortisol management: blood samples are taken to measure cortisol levels before and after synacthem administration

Question 12

what is the posterior pituitary regulated by

Answer 12

alternative signals such as vasopressin, barcoreceptors

Question 13

pituitary disease

Answer 13

too much hormone or too little if function is compromised
or glsnd too big
some tumours may be doing all three

Question 14

optic chiasm

Answer 14

x shaped structure formed by the crossing of optic nervesw

Question 15

when might the optic chiasm be compressed

Answer 15

due to pituitary tumours-loss of peripheral vision

Question 16

why is acth a difficult hormone to measure

Answer 16

its unstable and easily degraded by enzymes

short half life of 10 min roughly

peak levels occur early in morning and lowest at night - requiring precise timing

Question 17

indications for synacthen test

Answer 17

primary adrenal insufficiency- addisons - failure of adrenals themselves

secondary adrenal insufficiency- due to insufficient ACTH production by the pituitary gland

Question 18

HPA Axis Assessment

Answer 18

to assess adrenal glands in response to stress

Question 19

gold standard test for HPA axis assessment

Answer 19

insulin tolerance test

Question 20

clinical features assoc with anterior pituitary deficiency

Answer 20

GrowthHormone;Growthhormonedeficiency(GHD)-growthfailure
- → TSH; hypothyroidism (secondary)
- → LH/FSH; Hypogonadism (hypogonadropic hypogonadism)
- → ACTH;hypoadrenal(secondary)
→ Prolactin;noneknown

Question 21

clinical features assoc with posterior pituitary def

Answer 21

ADHdeficiency: Arginine vasopressin deficiency (diabetesinsipidus)

Question 22

causes of hypopituitaryism

Answer 22

• Tumours - non pituitary and pituitary
• Brain damage
• Iatrogenic
• Infection
• Genetic
• Idiopathic
  Granulomatous disease

Question 23

replacement therapy for hypopituitarism

Answer 23

hydrocortisone
thyroxine
sex steroids
GH
ADH

Question 24

testosterone replacement

Answer 24

skin gels
IM injection
prolonged IM injcetion

Question 25

which hormone regulates ACTH production

Answer 25

corticotropin releasing hormone - CRH

Question 26

which cranial nerve is most commonly affected by an enlarging pituitary gland

Answer 26

optic nerve - cranial nerve II

Question 27

prolactin functions

Answer 27

lactation and reproduction functions
stimulates milk production in mammary glands after childbirth - increases in pregnancy to prepare breasts

regulates menstrual cycle

in men it influences sperm production and maintains overall reproductive health