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