Endocrine System
What is an Endocrine system
Comprised of a widely distributed group of organs that work together to
maintain the body’s metabolic equilibrium
Achieve this by secreting molecules, which are frequently called
hormone
Hormones can be classified into several broad catego- ries
o Hormones that act by binding to cell surface receptors
This large class of compounds is composed of two groups
Peptide hormones ( Growth Hormone , Insulin
hormone )
Small molecules ( epinephrine )
o Hormones that act by binding to intracellular receptors, includes;
Steroids ( estrogen, progesterone, glucocorticoids)
Retinoids ( Vitamin A )
Thyroxine
Endocrine diseases generally are caused by ;
o Under production or over production of hormones
o End organ resistance to the effects of a hormone
o Neoplasms
Pituitary
, is a small, bean-shaped structure that lies at the base of the brain within
the confines of the sella turcica.
Along with the hypothalamus, the pituitary has a central role in the regu-
lation of most of the other endocrine glands
is composed of;
o the anterior lobe ( adenohypophysis )
o posterior lobe ( neurohypophysis )
The anterior pituitary, or adenohypophysis, produces trophic
hormones that stimulate the production of hor- mones from the
thyroid, adrenal, and other gland
The anterior pituitary, or adenohypophysis, produces trophic
hormones that stimulate the production of hor- mones from the
thyroid, adrenal, and other gland
Rarely, signs and symptoms of pituitary disease may be caused by
overproduction or underproduction of hypotha- lamic factors, rather than
a primary pituitary abnormality.
Symptoms and signs of pituitary disease fall into the following
categories:
Hyperpituitarism related effects
o Hyperpituitarism arises from excessive secretion of trophic
hormones. It most often results from an anterior pituitary adenoma
but also may be caused by other pituitary and extrapituitary lesion
Hypopituitarism related effects
o Hypopituitarism is caused by deficiency of trophic hormones and
results from a variety of destructive processes that may damage the
pituitary
o including ischemic injury, surgery, radiation, and inflammatory
reactions. In addition, nonfunctional pituitary adenomas may
encroach upon and destroy the normal anterior pituitary, causing
hypopituitarism.
Local mass effects:
o including sellar expansion, bony erosion, and disruption of the
diaphragma sellae.
Because of the close proximity of the optic nerves and
chiasm to the sella, expanding pituitary lesions often
compress decussating fibers in the optic chiasm.
This can give rise to visual field abnormalities, classically in
the form of defects in the lateral (temporal) visual fields—a
so-called “bitemporal hemianopsia”
As in the case of any expanding intracranial mass, pituitary
tumors may produce signs and symptoms of elevated
What is an Endocrine system
Comprised of a widely distributed group of organs that work together to
maintain the body’s metabolic equilibrium
Achieve this by secreting molecules, which are frequently called
hormone
Hormones can be classified into several broad catego- ries
o Hormones that act by binding to cell surface receptors
This large class of compounds is composed of two groups
Peptide hormones ( Growth Hormone , Insulin
hormone )
Small molecules ( epinephrine )
o Hormones that act by binding to intracellular receptors, includes;
Steroids ( estrogen, progesterone, glucocorticoids)
Retinoids ( Vitamin A )
Thyroxine
Endocrine diseases generally are caused by ;
o Under production or over production of hormones
o End organ resistance to the effects of a hormone
o Neoplasms
Pituitary
, is a small, bean-shaped structure that lies at the base of the brain within
the confines of the sella turcica.
Along with the hypothalamus, the pituitary has a central role in the regu-
lation of most of the other endocrine glands
is composed of;
o the anterior lobe ( adenohypophysis )
o posterior lobe ( neurohypophysis )
The anterior pituitary, or adenohypophysis, produces trophic
hormones that stimulate the production of hor- mones from the
thyroid, adrenal, and other gland
The anterior pituitary, or adenohypophysis, produces trophic
hormones that stimulate the production of hor- mones from the
thyroid, adrenal, and other gland
Rarely, signs and symptoms of pituitary disease may be caused by
overproduction or underproduction of hypotha- lamic factors, rather than
a primary pituitary abnormality.
Symptoms and signs of pituitary disease fall into the following
categories:
Hyperpituitarism related effects
o Hyperpituitarism arises from excessive secretion of trophic
hormones. It most often results from an anterior pituitary adenoma
but also may be caused by other pituitary and extrapituitary lesion
Hypopituitarism related effects
o Hypopituitarism is caused by deficiency of trophic hormones and
results from a variety of destructive processes that may damage the
pituitary
o including ischemic injury, surgery, radiation, and inflammatory
reactions. In addition, nonfunctional pituitary adenomas may
encroach upon and destroy the normal anterior pituitary, causing
hypopituitarism.
Local mass effects:
o including sellar expansion, bony erosion, and disruption of the
diaphragma sellae.
Because of the close proximity of the optic nerves and
chiasm to the sella, expanding pituitary lesions often
compress decussating fibers in the optic chiasm.
This can give rise to visual field abnormalities, classically in
the form of defects in the lateral (temporal) visual fields—a
so-called “bitemporal hemianopsia”
As in the case of any expanding intracranial mass, pituitary
tumors may produce signs and symptoms of elevated
