The three main patterns of hormone secretion are humoral,
hormonal, and neural. These hormone secretions are responsible for managing
different hormones. Below is a description of each stimulus.
The humoral stimuli are responsible for non-hormone chemicals and
the changes they make to blood levels. For example, high blood sugar would be
managed by the hormone insulin. Insulin’s job would be to bring the blood glucose
(sugar) levels back down.
The main function of hormonal stimuli is to release hormones
whenever stimulated by other hormones from the endocrine system, such as the
hypothalamus. For example, the hypothalamus and the pituitary gland are known
as the command center of the endocrine system. The hypothalamus actually
produces the hormones that stimulate other hormones belonging to the anterior
side of the pituitary gland.
The neural stimuli respond to nerve stimulation and will release
hormones when stimulated. For example, the flight-in-fight response. If the
body senses danger the neural stimuli will trigger hormone release of hormones
norepinephrine and epinephrine from the adrenal glands.
As mentioned above, the
hypothalamus and the pituitary gland are known as the command center of the
endocrine system. The hypothalamus is responsible for releasing hormones that
stimulate other hormones in the anterior pituitary gland. The hypothalamus and
the pituitary The relationship, as explained above, between the hypothalamus
and pituitary gland are able to communicate through releasing and inhibiting
hormones that travel through the hypophyseal portal system. This serves as a
bridge between the hypothalamus and the pituitary gland.
The Hydrophilic hormones are mostly amino acid-based peptides and
proteins. They are soluble in water but not in lipids. They are unable to cross
the cell membrane and require a transduction system to send signals across the
cell membrane. Hydrophobic hormones are made up of mostly steroids and
therefore are soluble in lipids, but not in water. They can also cross the cell
membrane unlike hydrophilic hormones.
Insulin and glucagon are hormones that are secreted from by the pancreas
and are in charge of regulating glucose levels in the blood. When glucose
levels are too high the pancreas releases insulin. Insulin then increases the
liver’s storage of glycogen which brings blood sugar levels back down. However,
if glucose levels are too low, the pancreas releases glucagon which breaks down
glycogen in order to raise blood sugar levels back up.
Here are the following descriptions of the hormones thyroid,
parathyroid, adrenal glands, pineal gland and the thymus gland.
o The thyroid is located in the
neck, in front of the trachea, where it wraps around it. One hormone that the
thyroid releases are calcitonin. Calcitonin is released whenever there is a
rise in blood calcium levels. By releasing calcitonin, the hormone is able to
reduce the blood calcium levels. One way of doing this is by increasing calcium
loss through the urine.
o The Parathyroid is located in
the thyroid gland towards the back. Most people have four parathyroid glands.
Two on each side. The parathyroid releases the parathyroid hormone also
referred to as PTH. PTH is responsible for regulating calcium levels.
o The Adrenal glands are
located on top of the kidneys. There are two glands total. One on each kidney.
They are responsible for regulating sodium and potassium ions through the
urine, sweat and, saliva.
o The Pineal gland is located
inside the bran, just behind the third cerebral ventricle, not too far from the
thalamus. Not much is known about the pineal gland, except that it produces the
melatonin hormone which helps regulate sleep.
o The Thymus gland is located
in the upper anterior part of the chest, between the lungs. Not much is known
about the thymus gland, but what is known is that it plays a role in the immune
system. The thymus gland produces the hormone thymosin, which helps contribute
to the disease-fighting T lymphocyte cells.