1.
What
gland is it produced in?
a.
The
inner region, adrenal medulla, of the adrenal glands located on top of both
kidneys.
2.
Chemical
Pathway – what does this mean/Structure etc.
a.
Cells
in the nervous and endocrine system work together in an environment of what our
senses perceive as danger, stress, or threat, initiating the fight or flight
response.
This elicits instantaneous and simultaneous
responses throughout the body
b.
Sensory
nerve cells pass the signal to the hypothalamus in the brain. Neurosecretory
cells in the hypothalamus transmit a signal to the pituitary gland compelling
the cells there to release a chemical messenger into the bloodstream.
Simultaneously, the hypothalamus transmits a nerve signal down the spinal cord.
The adrenal gland will receive both the chemical messenger and the nerve
impulse.
c.
The
adrenal glands (located on top of the kidneys) receive the signals initiated by
cells in the hypothalamus, activating the release of epinephrine into the
bloodstream.
d.
When
chemical messengers arrive via the bloodstream, they dock on to receptors and
begin cell signaling that results in the production of cortisol. Cortisol is
released into the blood stream, resulting in an increase in blood pressure,
increase in blood sugar levels, and suppression of the immune system and
digestive system.
3.
Water
soluble or Fat soluble and Structure
– type and contrast it with the opposite type.
a.
Epinephrine
is a water-soluble molecule derived from amino acids (the building blocks of
protein). These hormones are stored in endocrine cells until they are needed.
They act by binding to protein receptors on the outside surface of the cell.
The binding alerts a second messenger molecule inside the cell that activates
enzymes and other cellular proteins or influences gene expression.
b.
Most
water-soluble hormones can travel freely in the blood because they
"like" water. They are repelled by lipid and fatty structures such as
the membranes that surround a cell and its nucleus. Because of this repulsion,
these hormones generally bind to receptor sites on the outside of the cell and
signal from there.
c.
Fat-soluble
hormones, like the sex hormone steroids estrogens and androgens, are fat
soluble and water repellent. They "like" lipid or fatty structures (such
as those surrounding cells and are repelled by watery areas). Steroids
generally travel to their target cells attached to a special carrier protein
that is water soluble. (such as, sex steroid hormone binding globulin and serum
albumin). The hormones detach before passing into the cell where they bind to
receptors.
4.
Type
of cellular receptor
a.
Epinephrine,
which binds to two types of GPCRs, is important in mediating the body’s
response to stress, when all tissues have an increased need for glucose and
fatty acids. These principal metabolic fuels can poured into the blood in a
matter of seconds by the breakdown of glycogen in the liver and of
triacylglycerol in adipose storage cells.
b.
“In
mammals, the liberation of glucose and fatty acids can be triggered by binding
of epinephrine (or norepinephrine) to β-adrenergic receptors on the surface of
hepatic (liver) and adipose cells. Epinephrine bound to similar β-adrenergic
receptors on heart muscle cells increases the contraction rate, which increases
the blood supply to the tissues. Epinephrine bound to β-adrenergic receptors on
smooth muscle cells of the intestine causes them to relax. Another type of
epinephrine receptor, the α2-adrenergic receptor, is found on smooth muscle
cells lining the blood vessels in the intestinal tract, skin, and kidneys.
Epinephrine bound to α2 receptors causes the arteries to constrict, cutting off
circulation to these peripheral organs. These diverse effects of epinephrine
are directed to a common end: supplying energy for the rapid movement of major
locomotor muscles in response to bodily stress. As discussed in more detail
later, β- and α-adrenergic receptors are coupled to different G proteins. Both
β1- and β2-adrenergic receptors are coupled to G proteins (Gs), which activate
adenylyl cyclase. In contrast, α1 and α2 receptors are coupled to two other G
proteins, Gq and Gi, respectively. Gi inhibits adenylyl cyclase, and Gq
stimulates phospholipase C to generate IP3 and DAG as second messengers.”
5.
What
type of feedback loop is it?
a.
Positive.
6.
Action
of hormone or its function – specific
a.
It
regulates heart rate, blood vessel, air passage diameters, and metabolic
shifts. It also controls our instinctive fight or fight response.
b.
After
epinephrine is released, the supply of oxygen and glucose to muscles and the
brain is increased. There is a rise in stroke volume (the volume or quantity of
blood pumped by a ventricle due to a single heartbeat) and the heart rate
increases. The hormone also dilates the pupils and constrict the arterioles
present in the skin. The secretion of adrenaline also brings up the sugar level
in the blood as well as suppressing the function of the immune system and
digestive system.
7.
What
is this regulated by?
a.
Epinephrine
is regulated by the central nervous system. The sympathetic nervous system and
the Adrenocorticotropic hormone both play important roles in the synthesis of
epinephrine.
