endocrinology 3 adrenal function Flashcards
how many glands are in the adrenal gland
2 distinct glands that come from 1 organ in development
what is the inner and outer part of the adrenal gland
Inner: adrenal medulla
Outer: adrenal cortex
what does the adrenal medulla develop from
Neural crest cells
what system is the adrenal medulla part of
Sympathetic nervous system
what does the adrenal medulla seceret
Catecholaminergic hormones
-epinephrine(80%) and norepinephrine (20%)
what does the adrenal cortex develop from
Mesothelial cells of the intermediate mesoderm
what is the adrenal cortex part of
Endocrine system (not nervous systems
what does the adrenal cortex respond to
hormones
what does the adrenal cortex secrete
Steroid hormones
what part of the adrenal gland is a modified sympa ganglion
Adrenal medulla
appart from the adrenal medulla, what else secretes norepinephrine
Postganglionic neurons in the SNS
what converts Norepinephrine to epinephrine in the adrenal medulla
Phenyl-N-methyltransferease
what has the greatest affinity for epinephrine
Beta-adrenergic receptors
what has the greatest affinity for norepinephrine
Alpha-adrenergic receptors
what tissues can E and NE bind to
organs and tissues not directly innervated by postganglionic neurons
- liver, skeletal muscle and fat
what happens when Epinephrine acts on tissues not directly innervated by postganglionic neurons
Increases availability of metabolic fleul
- stimulate lipolysis, glycogenolysis, gluconeogenesis
how does the adrenal medulla enhance sympa response
release hormones to reach added targets without using neural circuits that can also last longer
zones of the adrenal cortex
zona glomerulosa: outer
Zona Fasciculata: middle
Zona reticularis: innermost, adacent to medulla
why do the different zones of the adrenal cortex produce different hormones
contain different steroidogenic enzymes within the cells
what stimulates most of the steroids to be synth and secreted in the Adrenal cortex
ACTH (not aldosterone though)
what hormones does the zona fasciulata make
Glucocorticoids:
Cortisol
Corticosterone
what hormones does the zona glomerulosa make
Mineralcorticoids:
aldosterone
what hromones does the Zona reticularis makde
Sex:
DHEA-s
androstenedione
what kind of steroid is aldosterone
Mineralocorticoid
what enzymes are found in the zona fasciulata, to make their hormones
PRegnenolone
what enzymes are found and what are lacking in the zona glomerulosa to make aldosterone
Aldosterone synthase
lack: enzymes that convert corticosterone to cortisol or androngens
what is the principle action of aldosterone
Stimulate Na and H2O retenion by the kidney
- maintain blood volume and blood pressure
what happens to your Pee when your body releases aldosterone
increase in urinary excretion of K and H
what is the steps of Aldosterone action on the tubular epithelial cells of the kidney
- aldosterone-receptor complex binds DNA
- Stimulates Synth of proteins to increase Na and H2O reabsorption from tubular fluid back into blood
what are the effects of aldosterone
More Na channels in apical membrane
More Na-K ATPase in basolateral membrane
increased synth of mitochondrial enzymes used in ox phos (electron transport system)
how does Na get from the lumen of the tube, backinto the blood
- Na enters the luminal surface of the epithlium via Sodium permease
- Na leaves the cell to go to the blood via a Na-K pump
what leads to the secretion of aldosterone
increase in plasma angiotensin increase in plasma K Decrease in plasma pH sdrop in systeic bo inhibited by increase in Na
what is angiotensin II
Hormone produced in response to renin
what is renin
hormone release by kidney in response to deecrease in Na or BP
what is the physiologically important hormone in humans
Clucocorticoids
what is the major effect of glucocorticoids
increase metabolic fuel availability for use in tissues
what is glucocorticoids effect on the liver
increase in gluconeogenesis
what is glucocorticoids effect in muscle
increase proteolysis
decrease glycose uptake
what is glucocorticoids effect in fat
Decrease glucose uptake
what are the whole body effects of glucocorticoids
increase lipolysis
decrease immune and inflammatory response
decrease growth and reproductive function
what is glucocorticoids effect in blood vessels
action of beta adrenergic receptors in smooth muscle to regulate blood pressure
what stimulates synth and secretion of glucocorticoids
ACTH
negative feedback given by cortisol
acts on both CRH and ACTH
what is the precursor of other sex steroids
DHEA
what is the roll of DHEA in circulation
circulating reservoid for conversion in peripheral tissues containing steroidogenic enzymes
strength of DHEA
weak androgenic action
what does the peripheral concentration of DHEA reflect
overall activity of the adrenal cortex
how is androstenedois is synthesized
by enzymatic conversion of DHEA
strength of Androstenedoine
stronger androgen than DHEA but weaker than Testosterone
what is the roll of Androstenedoine
provides non-gonadal source of test and estradiol
when is DHEA imporant as a reproductive steroid
an important source of reproductive steroids prior to puberty and postmenopausal women
why are adrenal sex steroids important
regulate mood libido hair growth erythropoiesis acne
what stimulates synth and secretion of adrenal androgens
ACTH (not GnRH and LH)
why is the stress response is important
Maintenance of homeostasis and needed for survival
allows body to respond to deviations from normal
good
what is a stress response
Is a response of the stress axis to stressors that stimulate Hypothalamic CRH neurons and inputs to the SNS
what is the stress axis
Hypothalamus
Anterior pituitary
adrenal cortex
what does SNS activation lead to in the stress response
specific organ responses and increased circulating epinephrin
rapid response in s. mucls stimulation and inhibition
widespread effects of epinephrine
what does activation of the stress axis lead to
increased secretion of cortisol
what does the increased secretion of cortisol from the activation of the stress axis lead to
increases the availability of metabolic fuel and other function
- inhibits action of insulin
response time of SNS activation and Stress axis
SNS: rapid
Stress axis: delayed
what are the 3 goals of the stress response
Maintain blood pressure
Mobilize and increase availability of metabolic fuel
inhibit non-essential function
what tends to be the hormones released via human stress
E and NE from adrenal medulla
and cortisol from the adrenal cortex
what does the SNS do during stress for quick glucose
Increase hepatic and muscle glycogenolysis
what does the SNS help to breakdwon
Breakdown adipose tissue triglycerides
what does the SNS do for the heart during stress
increased cardiac function
how does the blood change during human stress response due to the SNS
diverts bllood from viscera to skeletal muscles by vasocontrsiction in viscera and vasodilation in skeletal muscles
how does the lungs change from stress due to the SNS
increased ventilation by stimulating brain breathing centers and dilating airways
what does the presence of cortisol during stress do to organic metabolism
- Protein catbolism in bone lymph muscle and elseway
- stimulate liver uptake of amino acids and convert to glucose (gluconeogenesis)
- maintenace of plasma glucose concetration
- stimulate triglyceride catabolism in adipose tissue, with release og glycerol and fatty acids in blood
what does the presence of cortisol during stress do to the vessels
Enhanced vascular reactivity (increase ability to constrict in response to NE)
what part of human stress responds to the damaging influences of stress
Cortisol
what part of human stress inhibits inflammation and specific immune response
Cortisol
what part of human stress inhibits nonessential functions
Cortisol
what happens if cortisol is high for a long time
Can become damaging
how long does it take for the catabolic effect of stress to go away
can last long as llong as stresor is present
what immunologic effect does cortisol have
Anti-inflammatory and anti-immune effects
- inhibit cytokines and phagocytosis
- block prolieration of white blood cells
pros and cons of stopping immunologic effects of cortisol
Conserves energy
damaging if chronic
problems with movment of metabolic fuels
leads to atherosclerosis and hypertension
what does HSV while having a psychiatric illness lead to
Increased recurrences and duration of outbreaks
what does having influenza and family dysfunction lead to
An increased frequency and severity of illness
what does hep B plus exams lead to
delayed antibody response to vaccine
what is addison’s disease
adrenal insufficiency
causes of primary insufficiency from addison’s disases
Disease
Congenital - improper function, missssing enzymes,
Autoimmune
causes of a secondary insufficiency from addison’s disaes
Pituitary problem
Glucocorticoid therapy
how an glucocorticoid therapy lead to addison’s insufficiency
has feedback effects on CRH and ACTH
- can impair a normal stress response
why does secondary insufficiency from addison’s disease matter to dentist
Complications with maintaining blood pressure during anethesia, diminished immune and inflammatory response
symptoms of adrenal insufficinecy
Low cortisol and high ACTH weakness, lethargy , decreased appetite Low blood pressure Low glucose when fasting Hyperpigmentation due to lack of neg feedback control of POMC production
how do you treat addison’s dissorder
exogenous gluccorticoids
dietary control
what casues Hypercortisolinemia or cushing’s disase
typically a pituitary tumor
how to treat hypercortisolinemia/cushing’s
removing tumor
symptoms of high cortisol
Tissue catbaolism (bone, skin, muscle)
Diabetes like symptoms
impaired immune
hypertension
