Exam 1 -- Pt 5: Adrenals Flashcards
What is another name for the adrenal glands?
suprarenal glands (=”above the kidney”)
T/F. The adrenal glands hormones are not required for maintenance of life.
FALSE– They ARE REQUIRED for maintenance of life!!!!
What are the two “parts” of the adrenal gland? Where are they derived from and what hormone types do they secrete?
- outer Cortex–> mesodermal orgin; secrete steroids
2. inner Medulla–> chromaffin cells from ectodermal cells of neural crest; secrete catacholamines (Epi, NE)
What are the layers from outside in of the adrenal gland? (4)
- Zona glomerulosa
- Zona fasciculata
- Zona reticularis
- Adrenal medulla
(1-3 = adrenal cortex)
What hormones are released from:
- Zona glomerulosa
- Zona fasciculata
- Zona reticularis
- Adrenal medulla
- Mineralcorticoids (Ex: adlosterone)
- Glucocorticoids (Ex: cortisol, corticosterone, cortisone)
- Androgens (Ex: DHEA)
- Stress hormones (Epi and NE)
Where are the adrenal glands located?
in the retroperitoneal cavity on top of each kidney
What percentage of secretion does the Medulla have for the adrenals? What does it secrete?
(ectoderm derived)
20%
Secretes catacholamines (Epi and NE)
What percentage of secretion does the Cortex have for the adrenals? What does it secrete?
(mesoderm derived)
80%
Secreted Steroid hormones:
1. Mineralocorticoids (zona glomerulosa)
2. Glucocorticoids (primarily zona fasciculata)
3. Andorgens (primarily zona reticularis)
What is the mineralocorticoid that the adrenal cortex secretes?
aldosterone
What do mineralocorticoids have control over?
sodium and potassium
What stimulates the release of aldosterone from the adrenal cortex?*
angiotension II
What controls the secretion of mineralocorticoids?
mainly by renin-angiotensin system (kidney) via angiotension II, which stimulates aldosterone synthase
When would the renin-angiotension-aldosterone system kick in?
when blood pressure falls and kidney filtration levels drop, renin-angiotensin will assist increase of glomerular filtration
What affect does angiotensin II have on blood vessels?
causes them to constrict
What is the function of aldosterone?
increases reabsorption of Na and water; therefore increasing blood pressure and fluid volume
What organs are involved in the Renin-Angiotensin-Aldosterone System?–How?
- Kindey–> produces renin, which activates…
- Liver–> tp convert angiotensinogen to Angiotensin I, then…
- Lungs–> converts it to Angiotensin II with ACE
- Adrenal –> releases aldosterone due to stimulation by Angiotensin II
What are the glucocorticoids secreted by the adrenal cortex?
cortisol, corticosterone, cortisone
What do glucocorticoids affect?
- metabolism of glucose, proteins, and fat
- has anit-inflammatory activity*
What is the secretion of glucocorticoids controlled by?
ACTH (adrenal corticotropic hormone)–from anterior pituitary
What are two drugs that inhibit glucocorticoids?
- Metyrapone
2. Ketoconazole
What is Metyrapone do?
inhibits 11beta-hydroxylase; prevents production of corticosterone and cortisol
What is ketoconazole used for?
to treat fungal infections
inhibits several steps, including cholesterol desmolase (step from cholesterol–> pregnenolone)
How common is Adrenal Insufficiency (AI)? How serious is it?
rare; and potentially life-threatening
What is a type of Androgen released by the Adrenal cortex?
Dehydroepiandrosterone (DHEA)
What controls the secretion of Androgens from the adrenal cortex?
ACTH (adrenal corticotropic hormone) from and anterior pituitary
(also controls glucocorticoids secretion too)
Androgens have similar functions to what other structure?
testes
What involves masculinization in females, suppression of gonadal fxn in both sexes, early development of pubic/axillary hair, and increase levels for 17-ketosteroids?
Adrenogenital syndrome
What is increased in Adrenogenital syndrome?
increased synthesis of adrenal androgens–> high levels of DHEA and androstenedione
What would cause Adrenogenital syndrome to develop?
a deficiency of 21-beta hydroxylase
- which increases androgen production and
- decreases mineralcorticoid and glucocorticoid production
What hormone do the adrenals produce the most of on an average day?
Cortisol at 20 mg/day
(Androgens 10-15 mg/day
Corticosterone 2 mg/day
Aldosterone .15 mg/day)
T/F. The Adrenal cortex and medulla often behave as a functional unit.
True
Which is fast acting, the medullary hormones or the cortical hormones?
medullary hormones are fast acting; the cortical hormones are slower acting
What are three things that the slower acting cortical hormones serve as?
- maintain or increase sensitivity to medullary hormones
- maintain or enhance capacity of tissue to respond to medullary homrones
- act as modulators rather than initiators of responses
What are the two hormones released by the adrenal medulla?
Epinephrine and Norepinephrine
Which medullary hormone increases blood sugar levels, increases HR, increases contractility of heart, and relaxation of smooth muscles in airway?
Epinephrine
What medullary hormone increases narrowing of blood vessels, low blood pressure, and may induce septic shock?
Norepinephrine
What medullary hormone stimulates the liver to do catabolism of glycogen to glucose?
epinephrine
What is the “emergency hormone” for fight or flight?
epinephrine
T/F. Th e only adrenal medullary hormone NE increases levels of free fatty acids.
False- BOTH Epi and NE increase levels of free fatty acids
What is the precursor for all adrenocortical steroids?
cholesterol
What is deficient with a 17-alpha hydroxylase deficiency?
- aldosterone
- cortisol
- DHEA and Androstenedione
What is deficient with a 17,20 lyase deficiency?
- DHEA and Androstenedione
What is deficient with a 3-beta Hydroxysteroid dehydrogenase deficiency?
- Aldosterone
- Cortisol
- Androstenedione
What is deficient with a 21-beta Hydroxylase deficiency?
- Aldosterone
- Cortisol
What is deficient with a 11-beta Hydroxylase deficiency?
- Aldosterone
- Cortisol
What is deficient with an Aldosterone synthase deficiency?
- Aldosterone
How does cholesterol circulate?
bound to LDL
Where are receptors located for LDLs?
in membranes of adrenocortical cells; take up by endocytosis and esterfied and stored in cytoplasmic vesicles until needed for synthesis of steroid hormones
What adrenal hormones have anti-inflammatory effects?
glucocorticoids
What adrenal hormone stimulates gluconeogenesis and storage of glycogen?
glucocorticoids
What are glucocorticoids affect on the immune system?
suppresses the immune response, can suppress the thymus
What impact do glucocorticoids have on the glomerular filtration rate (GFR)?
increases it
- causes vasodilation of the afferent arterioles
- increases renal blood flow and GFR
What does cortisol (type of glucocorticoid) have a metabolism impact on? What does this increase synthesis of?
protein, fat, CHO in order to increase glucose synthesis
What hormones are essential for survival during fasting? Why?*
Glucocorticoids, b/c they simulate gluconeogenesis