endocrinoly 3- the adrenal gland Flashcards
where are the adrenal glands located?
on top of each kidney
the adrenal gland is actually two _______ that form what?
two distinct glands
form one organ
the adrenal _______ is the inner portion of the gland. what does it develop from?
adrenal medulla
develops from neural crest cells
t/f: the adrenal medulla is part of the sympathetic nervous system
true
what does the adrenal medulla secrete?
epinephrine and norepinephrine
the _____________ makes up the outer portion of the adrenal gland. how many layers is it arranged into?
adrenal cortex
arranged into 3 layers
what does the adrenal cortex develop from? what system is it part of?
develops from intermediate mesoderm
part of the ENDOCRINE system (not nervous)
the adrenal medulla is a modified _____________
sympathetic ganglion
what do the preganglionic neurons release onto the adrenal medulla?
acetylcholine (ACh)
chromaffin cells have no _______, and instead secrete what substances?
have no axons
secrete NE and E
what does the action of phenyl-N-methyltransferase lead to?
the conversion of norepinephrine to epinephrine
occurs in the chromaffin cells of the adrenal medulla
the effects of NE and E as hormones mimic what?
the sympathetic nervous system acting via synapses with target organs
t/f: norepinephrine remains in the blood longer than epinephrine
false
name the 3 zones of the adrenal cortex
zona glomerulosa
zona fasciculata
zona reticularis
which zone of the adrenal cortex releases mineralcorticoids? what hormone is produced?
zona glomerulosa
releases ALDOSTERONE
which zone of the adrenal cortex releases DHEA and androstenedione? what category of hormones are these?
zona reticularis
androgen steriods- sex hormones
cortisol and corticosterone are both released by the _______________. What type of hormones are these?
zona fasciculata of the adrenal cortex
they are GLUCOCORTICOIDS
steroids from the adrenal cortex are released in response to ______, except which hormone?
in response to ACTH
Aldosterone is the exception- its secretion is regulated by other signals
what is the major target of Aldosterone? what are the effects?
targets the Kidney
- stimulates Na+ and water RETENTION by the kidneys
the zona glomerulosa contains high levels of ________, and is deficient in enzymes that convert corticosterone to what?
aldosterone synthase
deficient in enzymes that convert corticosterone into cortisol or androgens
where is aldosterone synthase found?
in the zona glomerulosa (of the adrenal cortex)
secretion of aldosterone is stimulated by:
- increase in plasma ANGIOTENSIN 2, ACTH, or potassium
- decrease in plasma pH
- decrease in blood pressure
increased ______ intake will inhibit aldosterone secretion
sodium
what are the 3 ways in which aldosterone increase reabsorption of Na+?
1) increase # of sodium channels
2) increase # of Na/K-ATPase pumps
3) increase ATP output from mitochondria (to supply pump)
the zona fasciculata secretes __________
glucocorticoids
what regulates glucocorticoid synthesis/secretion
ACTH
ATCH is stimulated by ____. what hormone has a negative feedback effect on both of these
stimulated by CRH
CORTISOL has a negative feedback on both
what are the major effects of glucocorticoids?
increase metabolic fuel availability and use
what are the minor effects of glucocorticoids that become important during a stress response?
- helps maintain blood pressure
- inhibits non-essential functions
DHEA is the precursor to what other hormones?
precursor of other sex steroids
____________ is the extragonadal source of testosterone and estradiol that can be made from DHEA
androstenedione
what regulates androstenedione?
ACTH
NOT GnRH
what are the effects of adrenal sex steroids?
mood effects, hair growth, erythropoiesis (red blood cells)
the stress response is critical for maintaining __________
homeostasis
what is a stress response?
responses of the stress acid to a stressor that stimulates HYPOTHALAMIC CRH neurons and inputs to the SNS
what does SNS activation as a result of the stress response cause?
specific organ responses
increased circulating epinephrine from adrenal medulla
activation of the HPA axis results in what?
increased cortisol secretion
name the 3 primary goals of the stress response
1) maintain blood pressure
2) mobilize metabolic fuel or increase availability
3) inhibit non-essential function
cortisol has permissive actions on _________ receptors.
catecholamine receptors
found on smooth muscle of vasculature
how does cortisol maintain circulating conc. of blood glucose?
stimulating synthesis of liver enzymes for gluconeogenesis and glycogenolysis
____________ are highly catabolic
glucocorticoids
what is Addison’s Disease?
Adrenal insufficiency
NOT a complete lack of cortisol
what are the causes for a primary insufficiency of adrenal hormones?
disease
congenital disorders
autoimmune disorder
what are the causes for a secondary insufficiency of adrenal hormones?
(something happening UPSTREAM of the gland)
- pituitary problem- no ACTH secretion
- glucocorticoid therapy
what are the symptoms of Addison’s disease? how is it treated?
- LOW cortisol, HIGH ACTH
- hyperpigmentation
treat with exogenous glucocorticoids
what causes Cushing’s disease?
hypercortisolinemia
elevated adrenal gland output
Cushing’s syndrome is usually due to a ________ tumor
pituitary
what hormone is relieved of negative feedback during Cushing’s syndrome?
ACTH
does not get neg feedback from circulating adrenal hormones
the symptoms of Cushing’s syndrome are related to elevated basal concentrations of _______
cortisol
what are the symptoms of cushing’s syndrome?
- excess catabolism of skin, bone and muscle
- diabetes-like symptoms (cortisol is anti-insulin)
- impaired immune function
- threat of hypertension
what is the treatment for Cushing’s disease?
surgical removal of tumor
when treating patients with Cushing’s disease, what must a dentist be concerned with?
excess cortisol impares normal immune function
- slow healing
thin bone
increased bleeding- from high BP
what are the ramification of Addison’s disease in dental patients?
- under anesthesia, the HR and BP will drastically drop
peripheral concentrations of ______ can indicate adrenal activity
DHEA
