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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
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• Symptoms and signs of pituitary disease fall into the following
categories:
• Hyperpituitarism related effects
o Hyperpituitarism arises from excessive secretion of trophic
hormones
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In addition, nonfunctional pituitary adenomas may
encroach upon and destroy the normal anterior pituitary, causing
hypopituitarism
...

§ 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
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§ acute hemorrhage into a pituitary neoplasm is asso- ciated
with rapid enlargement of the lesion and loss of
consciousness

Thyroid
• Your thyroid is a small, butterfly-shaped gland located at the front of
your neck under your skin
• thyroid’s main job is to control the speed of your metabolism (metabolic
rate), which is the process of how the body transforms the food you
consume into energy
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Although your thyroid makes the most of this
hormone, it doesn’t have much of an effect on your metabolism
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o Reverse triiodothyronine (RT3): Your thyroid makes very small
amounts of RT3, which reverses the effects of T3
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thyroid hormones affect the following bodily functions:
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How your body uses energy (metabolism)
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Breathing
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Body temperature
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Mental activity
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Fertility
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Hyperthyroidism (overactive thyroid)
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Thyroid cancer
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This causes aspects of your
metabolism to slow down
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It is treatable
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Thyroiditis (inflammation of the thyroid)
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A nonfunctioning thyroid gland (when the thyroid doesn’t work correctly
from birth)
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Thyroid gland removal
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This causes aspects of
your metabolism to speed up
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It is treatable
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Thyroid nodules
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Postpartum thyroiditis (inflammation of the thyroid that happens after
giving birth)
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Over-treatment of hypothyroidism through medication
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Goiter
Goiter is an enlargement of your thyroid gland
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Simple goiters: These goiters develop when your thyroid gland doesn’t
make enough hormones to meet your body's needs
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Endemic goiters: These goiters occur in people who don't get enough
iodine in their diet (iodine is necessary to make thyroid hormone)
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Sporadic goiters: These goiters have no known cause in most cases
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Thyroid cancer
Thyroid cancer is cancer that begins in your thyroid tissues
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Treatments for most thyroid cancers are very successful
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Thyroid cancer types include:
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Papillary: Up to 80% of all thyroid cancer cases are papillary
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Medullary: About 2% of thyroid cancer cases are medullary
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Anaplastic: About 2% of thyroid cancer cases are anaplastic

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