The cells of the pancreatic islets occur in the following percentages: Alpha - 70%, Beta - 20%, Delta - 5-10%, PP cells (rare)
Type I diabetes is insulin dependent. It involves the auto immune destruction of beta insulin producing cells in the pancreas
The thyroid gland is unique in that it is the only gland in which large quantities of secreted product are stored outside of the cells. Storage is in the colloid of the follicle as precursor called thyroglobulin. On stimulation of the thyroid by TSH Thyro
The thyroid gland is
in origin. It is comprised of large
that are made up from surrounding
which is a hormone precursor and is secreated into the follicle lumen.
The activity of the thyroid gland is modulated by
released from the
Calcitonin has a key role in decreasing plasma Ca2+ levels by inhibiting osteoclast bone re-modelling. Accidental removal of the parathyroid glands during surgery will have severe effects
The parathyroid glands are found to the posterior of the
which is critical in the maintenence of
levels in the blood.
Parathyroid glands also contain
cells, which are found in higher concentrations in older people an are thought to be transitional derviatives.
When Ca2+ levels in the blood fall,
cells of the
which acts on the bones and kidney, causing an
plasma Ca2+ levels.
This hormone also causes an increase in plasma levels of
which increases the absobtion of Ca2+ and Mg2+ from the gut.
An increase in plasma Ca2+ stimulates the
from parafollicular cells, which inhibits
and brings about a fall in plasma Ca2+ levels.
选择要在Apple App Store上查看的Topgrade应用程序。