Endocrine System Flashcards
What breeds have adenohypophyseal hypoplasia as a genetic defect?
guernsey and jersey cattle
What plant causes cyclopia when ingested by pregnant sheep?
veratrum californicum (skunk plant)
Why is there prolonged gestation during fetal adenohypophyseal hypoplasia?
failure of fetus to convert pregesterone to estrogen surge
What causes pituitary cysts?
failure of rathke’s pouch to differentiate into pars distalis
What characterizes pituitary dwarfism?
slow growth, alopecia, hyperpigmentation of skin
What lesion is seen with pituitary cysts?
enlarging cyst in sella turcica and absence of adenohypophysis
What pituitary neoplasm is seen in young animals?
craniopharyngiomas
What 2 pituitary neoplams are seen in older animals?
adenomas and carcinomas
How can adenomas of the pituitary gland be distinguished from nodular hyperplasia?
large size and presence of a capsule
What is the most common pituitary neoplasm in horses?
adenomas of the pars intermedia
What are the sequlae of INACTIVE adenomas of the pars intermedia in dogs?
hypopituitarism and diabetes insipidus
What are the sequalae of ACTIVE adenomas of the pars intermedia in dogs?
cushings disease
What happens with adenomas of the pars intermedia in horses?
compression of hypothalamus –>PU/PD, hyperhidrosis, hypertrichosis (cushings)
What lesion will be seen in a dog with ACTH-secreting adenoma?
bilateral enlargement of the adrenal glands
What species have been seen with endocrinologically inactive chromophobe adenoma?
dogs, cats, rodents, parakeets
What is the sequlae of endocrinologically inactive chromophobe adenoma?
compression atrophy/space occupying lesion –> blindness
What is the sequlae of craniopharyngiomas in young animals?
failure to attain somatic maturation diabetes insipidis (no ADH) CNS dysfunction
Why do dogs with pituitary dwarfism have short life spans?
secondary endocrine dysfunction –>hypothyroidism, hypoadrenocorticocism
What pituitary neoplasm is functionally inactive but space occupying leading to panhypopituitarism in older dogs and cows?
pituitary gland carcinoma
What species get sporadic pituitary abscesses?
ruminants and swine
What is the cause of pituitary abscesses?
bacteria or mycotic agents
What form of diabetes insipidus interferes with the ADH synthesis or secretion?
hypophyseal form
What form of diabetes insipidus is a heriditary defect resulting in lack of adenylate cyclase in kidney?
nephrogenic form (cells don’t respond to ADH)
What can cause hypophyseal diabetes insipidus?
Growth disturbances that cause:
severance of infundibular stalk
or destruction of pars nervosa