Hypothalamus and Pituitary Tutorial

Question 1

what is a ENdocrine gland

Answer 1

secretes its hormones directly into the bloostream

Question 2

what is an EXocrine gland

Answer 2

secrete their hormones into a collection of ducts which are carried around the body

Question 3

what is the difference in onset and duration of action of endo vs exocrine glands

Answer 3

exocrine quicker response

endocrine longer duration as taken to kidney to made available for absorption

Question 4

match each hormone to its class:
steroid
protein and peptide
amine

insulin
adrenaline
testosterone

Answer 4

steroid- testosterone
protein and peptide- insulin
amine- adrenaline

Question 5

true or false- amine peptides and proteins are only synthesised on demand

Answer 5

false

Question 6

true or false- steroid hormones are mainly bound to proteins in the plasma

Answer 6

true

Question 7

true or false- amines, peptides and proteins stimulate and act on intracellular receptors

Answer 7

false - have cell surface receptors

Question 8

list these from shortest to longest half lives:
steroid
amine
peptide

Answer 8

amine- seconds
peptide- minutes
steroid- hours

Question 9

what connects the hypothalamus to the pituitary

Answer 9

the pituitary stalk

Question 10

what is the adenohypophysis

Answer 10

anterior pituitary

Question 11

what in the neurohypophysis

Answer 11

posterior pituitary

Question 12

what synthesises posterior hormones in the hypothalamus

Answer 12

supraoptic and paraventricular nuclei (neuroendocrine)

Question 13

how do hormones from the hypothalamus get to the anterior pituitary

Answer 13

cell bodies secrete into via portal veins

Question 14

what are the ‘releasing’ stimulatory hypothalamic hormones

Answer 14

growth hormone releasing hormone (GHRH)
prolactin releasing hormone (PRH)
thyrotrophin releasing hormone (TRH)
corticotrophin releasing hormone (CRH)
gonadotrophin releasing hormone (GnRH)

Question 15

what are the inhibitory hypothamalic hormones

Answer 15

somatostatin and dopamine

Question 16

what class are the hypothamalic hormones

Answer 16

all peptides except dopamine which is an amine

Question 17

what does dopamine inhibit

Answer 17

the release of prolactin (ant pit)

Question 18

what does somatostatin inhibit

Answer 18

growth hormone (ant pit)

Question 19

what is released from the anterior pituitary

Answer 19

GH 
ACTH (andenocorticotrophic hormone)
TSH
PRL
FSH (follicle)
LH (lutenising)

Question 20

what is released from the posterior pituitary

Answer 20

oxytocin

anti-diuretic hormone (ADH)

Question 21

what is the function of oxytocin

Answer 21

milk secretion and uterine contractions

Question 22

what is the function of ADH

Answer 22

increases water reabsorption at kidneys

vasoconstriction at vascular smooth muscle

Question 23

what are the actions of growth hormone

Answer 23

increases blood glucose by increasing gluoneogenesis in the liver
releases insulin GF (IGF-1) from the liver
decreases glucose uptake in muscles cells- increases it in brain cells
increases the rate of lipolysis in fat cells
has anabolic effect on the body
increase glucose and fatty acids
increased protein synthesis
decreased fat storage
increased soft tissue growth
increased bone growth

Question 24

what are common conditions in growth hormone excess

Answer 24

diabetes (T2), carpal tunnel syndrome, hypertension

Question 25

what does IGF-1 cause

Answer 25

increased bone growth increased soft tissue growth increased protein synthesis

Question 26

what changes can be seen in acrogmegaly

Answer 26

``` increase in hand and foot size prominent brow large nose and jaw pronounced cheekbones skin changes (thickens, sweating, acne) oral manifestations (enlargement of tongue and swelling of larynx, interdental separation) ```

Question 27

how can acromegaly's oral manifestations cause presentations

Answer 27

deep or coarser voice | obstructive sleep apnoea

Question 28

how is movement affected in acromegaly

Answer 28

joint pain, proximal muscle weakness, lethargy decreases movement decreased movement in hands and pain/ tingling sensations

Question 29

what behavioural problems arise in acromegaly

Answer 29

lethargy | polydispsia and uria

Question 30

why do you get hypertension in acromegaly

Answer 30

increased plasma fatty acids causes patty plaques

Question 31

what nerve is affected in carpal tunnel

Answer 31

median nerve

Question 32

what provides negative feedback for GH

Answer 32

IGF-1 negative on ant pit | GH negative on Hypothalamus

Question 33

what causes acromegaly

Answer 33

``` pituitary tumour (micro <1cm or macroadenoma >1cm) ectopic tumour ```

Question 34

what is gigantism

Answer 34

when children have a growth hormone secreting tumour of the pituitary gland- epiphyseal plates not closed so large bone growth

Question 35

in acrogmegaly what hormone can also be secreted in excess

Answer 35

prolactin (in one 1/3rd of patients)

Question 36

why can GH nnot diagnose acromegaly

Answer 36

as released in pulsatile manner - highest when asleep and in times of stress

Question 37

when is growth hormone low normally

Answer 37

in pregnancy

Question 38

what is the definitive test for acromegaly

Answer 38

oral glucose tolerance test

Question 39

how does oral glucose tolerance test diagnose acromegaly

Answer 39

oral glucose should suppress GH to <1 microgram/litre if no suppression then acromegaly

Question 40

what can IGF-1 test show

Answer 40

mean 24 hour secretion of growth hormone

Question 41

what scan is done to see if there is a tumour in acromegaly

Answer 41

MRI of the pituitary fossa

Question 42

what is the treatment for acrogmegaly

Answer 42

surgery- trans-sphenoidal radiotherapy- (with/without surgery) dopamine agonists (bromocriptine and cabergoline) somatostatin receptor agonists (octreotide and lanreotide) growth hormone antagonists (pegvisomant)- works on GH receptors not on tumour

Question 43

what can cause hypopituitarism

Answer 43

pituitary tumour radiation damage trauma infective (meningitis, syphilis, encephalitis) immunological (autoimmune) infiltrative (haemachromoatosis, sarcoidosis, secondary mets lesions)