Pituitary Gland Pathology

Question 1

Define autocrine signalling

Answer 1

receptors occur on the plasma membrane of the same type of cell that secretes the signalling molecules

Question 1

Define paracrine signalling

Answer 1

receptors occur on a different type of target cell located near the cell secreting the signalling moelcules

Question 2

Define intracrine signalling

Answer 2

receptors occur on the nuclear envelope of the cell that synthesized the signalling molecule

Question 3

Define endocrine signalling

Answer 3

receptors occur on a different type of target cell located distant from the cells secreting the signalling molecules, through the circulatory system

Question 4

Name the 4 types of signalling

Answer 4

autocrine
paracrine
intracrine
endocrine

Question 5

Define a steroid

Answer 5

cholesterol based (lipid soluble), function as nuclear receptors and transcription factors

Question 6

Define a catecholamine/iodothyronine

Answer 6

act on plasma membrane surface OR intracellularly

Question 7

What cells is the pars distalis made up of

Answer 7

acidophils, secrete peptide hormones
basophils, secrete glycoproteins
chromophobes, secrete corticotrophs

Question 8

What hormones are secreted by the neurohypophysis ?

Answer 8

oxytocin and ADH

Question 9

Define a primary hyperfunction

Answer 9

autonomous hypersecretion of hormone, typically neoplastic

Question 10

Define a secondary hyperfunction

Answer 10

increased trophic or releasing hormone from the hypothalamus/pituitary themselves OR decreased inhibitory hormones

Question 11

Define a primary hypofunction

Answer 11

Destruction, lack of formation of secretory cells or deficiency in synthesis of a hormone itself

Question 12

Define a secondary hypofunction

Answer 12

Decreased production of a trophic hormone, resulting in trophic atrophy

Question 13

Define canine juvenile panhypopituitarism

Answer 13

the failure of the oropharyngeal ectoderm to differentiate into the adenohypophysis (pituitary dwarfism)

animal ends up deficient in GH, TSH, prolactin, gonadotrophs and ACTH

grossly. animal appears normal until 2 months, when they have slower growth, retention of puppy hair and eventually complete alopecia.

Question 14

Define diabetes insipidus and name the 2 forms.

Answer 14

Acquired disorders of growth of the posterior lobe of the pituitary gland

hypophyseal form = inadequate ADH secretion, due to neurohypophysis destruction OR hypothalamic nuclei compression from a mass

nephrogenic form = an inability to respond to ADH due to kidney damage

Question 15

CS of diabetes insipidus

Answer 15

PU/PD

Question 16

What happens to the pituitary in the event of a loss of negative feedback ?

Answer 16

hyperplasia, hypertrophy and hyperfunction

Question 17

Common pituitary neoplasms

Answer 17

adenomas –> cortocotroph (ACTH-secreting), somatotroph (GH-secreting), lactotrophs and thyrotrophs
non functional adenomas
equine pituitary pars intermedia dysfunction (ePPID) (increased PI hormones)

Question 18

Define hypophysitis

Answer 18

inflammation of the pituitary gland, typically due to haematogenous arrival of systemic infection