The Adrenal Gland Flashcards
The adrenal glands are located on top of each ___ and are two distinct glands that form from ___ organ during embryonic development.
kidney; one
What is the inner portion of the adrenal gland called? where does it develop from?
adrenal medulla; neural crest cells
T/F. The adrenal medulla is part of the parasympathetic nervous system.
False, it is part of the sympathetic nervous system (fight or flight)
What is secreted from the adrenal medulla?
catecholaminergic hormones - epinephrine and norepinephrine
The adrenal ___ is the outer portion that develops from ___ cells in the ___ mesoderm.
cortex; mesothelial; intermediate
T/F. Similar to the adrenal medulla, the adrenal cortex is part of the nervous system.
False, it is NOT part of the nervous system
The adrenal cortex responses to blood-borne signals called ___ and it secretes several types of ___ hormone.
hormones; steroid
The adrenal medulla is a modified sympathetic ___ and there are no ___ neurons. Instead the postganglionic cells, called ___ cells, release epinephrine (80%) and norepinephrine (20%) into the blood.
ganglion; postsynaptic; chromaffin
Normally, the SNS includes ___ neurons that arise from the ___ and ___ regions of the spinal cord, the preganglionic neurons synapse in ___ with postsynaptic neurons whose ___ terminate on a variety of organs.
preganglionic; thoracic; lumbar; ganglia; axons
What enzyme is found in considerable amounts in the adrenal medulla can convert NE to E?
pheny-N-methyltransferase
___ (Alpha/Beta)-adrenergic receptors have greater affinity for E and ___ (alpha/beta)-adrenergic receptors have affinity for NE.
Beta; Alpha
T/F. Once secreted into the blood, these neurotransmitters (NE and E) are now called hormones.
True.
T/F. There is also an effect of E and NE on organs and tissues not directly innervated by postganglionic neurons including the liver, skeletal muscle and fat. In these tissues, E acts to increase the availability of metabolic fuel by stimulating lipolysis, glycogenolysis and gluconeogenesis.
True.
The adrenal ___ enhances the SNS response by releasing hormones that can reach additional targets without using neural circuits. And because the signal is blood-borne, the responses may last ___.
medulla; longer
Match the following zones of the adrenal cortex.
- Zona glomerulosa
- Zona fasciculata
- Zona reticularis
A. Inner
B. Middle
C. Outer
- C
- B
- A
Why do different zones within the adrenal cortex secrete a different class of steroids?
due to the presence and availability of different steroidogenic enzymes within the cells
What stimulates steroid synthesis and secretion from the adrenal cortex? What is the exception?
ACTH
except for Aldosterone
Aldosterone is a ___ produced by cells of the zona ___. These cells contain the enzyme ___ ___ and are deficient in the enzymes that convert ___ to cortisol or androgens.
mineralocorticoid; glomerulosa; aldosterone synthase; corticosterone
What is the principle action of aldosterone?
to stimulate Na+ and H2O retention by the kidney in order to maintain blood volume and blood pressure.
The mechanism by which aldosterone helps reabsorb Na+ and H2O in the kidney results in what being excreted in the urine?
increase urinary excretion of K+ and H+
The aldosterone-receptor complex binds to ___ and stimulates the synthesis of proteins that act to increase ___ and ___ reabsorption from the ___ fluid back into the ___.
DNA; Na+; H+; tubular; blood
Where are the Na+ channels located and what is the function of these channels?
apical membrane
increase reabsorption of Na+ from tubular fluid
Where are the Na+-K+ ATPases located and what is the function of this pump?
basolateral membrane
pumps Na+ back into the blood and therefore decreases K+ in blood or increases K+ excretion
___ enzymes used in oxidative phosphorylation (ETC) are used to produce ___ and fuel the Na+-K+ ATPase.
Mitochondrial; ATP
What has a minor effect on the secretion of aldosterone?
ACTH
Aldosterone is stimulated by an increase in plasma ___ ___, which is a hormone produced in response to renin. Renin is released by the kidney in response to a ___ in Na+ or blood pressure.
angiotensin II; decrease
The secretion of aldosterone is stimulated by an ___ in plasma K+ and a ___ in plasma pH or ___ in plasma H+.
increase; decrease; increase
This allows K+ and H+ to be removed from the blood and excreted in the urine
A drop in systemic blood pressure will cause the secretion of ___.
aldosterone
What can inhibit aldosterone secretion?
increase in Na+ intake
___, cortisol and corticosterone, are secreted by the cells of the zona ___.
Glucocorticoids; fasciculata
Which does glucocorticoids or cortisol increase or decrease?
- gluconeogenesis in liver
- proteolysis in muscle
- lipolysis
- glucose uptake in muscle and fat
- immune and inflammatory responses
- growth and reproductive function
The major effects are to increase metabolic fuel availability and use in tissues.
1 - 3 increase
4-6 decrease
T/F. Cortisol has a permissive action on Beta-adrenergic receptors in vascular smooth muscle to regulate blood pressure.
True. B-receptors maintain BP and cortisol keeps BP at a normal level by having receptors available to respond and regulate pressure.
What stimulates the synthesis and secretion of glucocorticoids? What has a negative feedback action on both CRH and ACTH?
ACTH
Cortisol
What zone of the adrenal cortex secretes sex steroids? What are the two major androgens secreted?
zona reticularis
dehydroepiandrosterone (DHEA) and androstenedione
What androgen is a precursor for other sex steroids but has relatively weak androgenic actions with peripheral concentrations that reflect the overall activity of the adrenal cortex?
DHEA
How is androstenedione produced?
by enzymatic conversion of DHEA
___ is stronger than DHEA, provides a non-gonadal source of ___ and ___ and is an important source of reproductive steroids prior to ___ and in ___ women.
Androstenedione; testosterone; estradiol; puberty; postmenopausal
What are important regulators of mood and libido, hair growth, erythropoiesis, and acne?
adrenal sex steroids
T/F. The synthesis and secretion of adrenal androgens is stimulated by GnRH.
False, they are stimulated by ACTH NOT GnRH…just because they are sex steroids doesn’t mean they are regulated by gonadotropin releasing hormone or gonadotropins!
What is critical for the maintenance of homeostasis and essential for survival?
stress
What is the stress axis?
hypothalamus - anterior pituitary - adrenal cortex
The ___ response is a response of the stress axis to a stressor that stimulates hypothalamic CRH neurons and inputs to the ___.
stress; CRH; SNS
What does SNS activation cause?
specific organ responses and increased circulating epinephrine
rapid response involving smooth muscle stimulation and inhibition
Activation of the stress axis is a ___ response that leads to increased secretion of ___, which causes increases in availability of metabolic fuel and other functions.
delayed; cortisol
T/F. Cortisol inhibits the actions of insulin.
True.
The primary goals of the stress response are to maintain ___ ___, mobilize and increase availability of metabolic ___, and ___ non-essential function.
blood pressure; fuel; inhibit
T/F. The actions of cortisol are not essential under non-stress conditions, but they can become damaging when cortisol is elevated for long periods of time and combined with acute activation of the SNS.
False, The actions of cortisol are ESSENTIAL under non-stress conditions, but they can become damaging when cortisol is elevated for long periods of time and combined with CHRONIC activation of the SNS.
Cortisol is highly ___ to use substrates to produce needed ___. Tissues can be rebulit when ___ is over but continue catabolic processes as long as stress is present.
catabolic; glucose; stress
Cortisol has ___ and ___ effects to inhibit cytokines and phagocytosis, and blood proliferation of ___. This ___ energy in the short term but is damaging with chronic stress.
anti-inflammatory; anti-immune; WBCs; conserves
What can cortisol increase in the blood as a result of the mobilization of metabolic fuels? Why is this bad?
It increases LIPIDS.
When lipids are combined with increased blood pressure it can lead to development of atherosclerosis and hypertension.
How do problems arise with the activation of cortisol?
When a continued physical or psychological stressor turns a short-term response into chronic activation of CHR neurons
What are the primary insufficiency causes of Adrenal insufficiency or Addison’s disease?
- disease due to loss of function or loss of gland
- congenital disorder
- autoimmune disorder
What are the secondary insufficiencies caused by Adrenal insufficiency or Addison’s disease?
pituitary problem - no ACTH or no aldosterone
glucocorticoid therapy - the use of exogenous corticosteroids has negative feedback effects on CRH and ACTH and can impair a normal stress response.
List the symptoms of adrenal insufficiency.
- low cortisol and high ACTH
- weakness, lethargy, decreased appetite
- low blood pressure
- low glucose when fasting
- hyperpigmentation due to lack of negative feedback control on POMC production
How do you treat symptoms of adrenal insufficiency?
treat exogenous glucocorticoids and/or dietary control
Hypercortisolinemia or ___ disease is typically due to a ___ tumor (or administering too much exogenous ___), and can be treated by removing the ___.
Cushing’s; pituitary; glucocorticoid; tumor
Symptoms of Cushing’s disease include excessive ___ catabolism in bone, skin and muscle, ___-like symptoms causing increased ___ and circulating ___ and redistribution of ___ stores. Also there is impaired ___ function and a threat to ___.
tissue; Diabetes; appetite; glucose; fat; immune; HTN
In dental patients, the primary concern is impairment of ___ function after a procedure, but HTN, osteorporosis and increased bleeding are also problematic.
immune
