Unit 2 - Adrenal Gland Flashcards
What are the layers of the cortex of the adrenal gland?
zona glomerulosa, zona fasciculata, zona reticularis
What hormone does zona glomerulosa secrete?
aldosterone
What hormone does zona fasciculata secrete?
cortisol and cortisone
What hormone does zona reticularis secrete?
androstenedione, testosterone, and estradiol
What hormones does the medulla secrete?
catecholamines
What layers of the adrenal cortex are under ACTH control?
zona fasciculata and zona glomerulosa (little effect)
What is the precursor for the biosynthesis of hormones of the adrenal cortex?
Cholesterol which is regulated by ACTH
What are the effects of cortisol on the intermediary metabolism?
they are opposite the effect of insulin and it potentiates (increases) the effects of glucagon, epinephrine and GH
What are the major effects of cortisol on the anterior pituitary?
decrease ADH, TSH, and GH
What are the major effects of cortisol on connective tissue?
decreased collagen synthesis
What are the major effectsof cortisol on the GI tract?
decreased mucosal barrier, ulcer formation, decreased Ca absorption
What are the major effects of cortisol on the fetus?
prepares the fetus organ systems for birth and triggers parturiton
What are the major effects of cortisol on the inflammatory and immune system?
decreased inflammatory and immune response - limit destruction of normal tissue during injury
What are the major effects of cortisol on bone?
decrease in calcium deposition
What is Cushing’s disease?
pituitary dependent hyperadrenocorticism - excessive ACTH decretion
What species are you most likely to see cushings in?
horses and dogs
What is Cushing’s disease also known as in horses?
Equine PPID - pituitary pars intermedia dysfunction
What are the mechanisms that lead to Equine PPID?
the cells in the pars intermedia lose hypothalamic dopaminergic inhibition leading to an increase in ACTH release
What is the treatment for Cushing’s disease in horses?
dopamine agonists
What are common symptoms associated with PPID?
PU/PD, hirsutism, laminitis
What are the treatments for Cushings disease in dogs?
The primary one is mitotane and the second is trilostane
What does mitotane do?
it is used for controlled destruction of the adrenal cortex
What does trilostane do?
it blocks cortisol synthesis
