The Endocrine System
T. Zack Crawford
What is the Endocrine System?
• A collection of glands that produce hormones
to regulate the body’s growth, metabolism,
and sexual development
• These hormones are released into the
bloodstream for transport throughout the
body.
• In general, the Endocrine system is in charge
of maintaining homeostasis, the property of a
stable body in terms of things like
temperature and pH
Example Hormone Functions
• Oxytocin – Released during and after childbirth.
Important for lactation and other maternal
behaviors.
• Dopamine – Important for social behavior,
controls reward, punishment, mood, cognition,
motivation, etc.
• Thyronines – Simulate body heat production,
bone growth, and metabolism.
• Thymosin – controls immune mechanisms,
matures T and B-cells.
Example Hormone Functions
• Insulin – regulates fat/carbohydrate metabolism
• Adrenaline – Controls “fight of flight” response,
can suppress non emergency processes, boost
oxygen and glucose supply, etc.
• Testosterone – developing male reproductive
tissues as well as promoting muscular and bone
growth.
• Progesterone – Involved in female menstrual
cycle and pregnancy, etc. Can inhibit immune
response to embryo, inhibit onset of labor,
increase core temperature during ovulation, etc.
An example negative feedback
mechanism of the endocrine system
An example if a negative feedback mechanism
is the blood calcium levels. Calcium receptors on
parathyroid cells activate in the absence of calcium.
This activation leads to the release of the
parathyroid hormone which will then release
calcium into the blood from various locations on
the body such as reservoirs in the bones. The
increase in calcium concentration in the blood will
then turn off the calcium receptors and inhibit the
release of the parathyroid hormone.
Insulin and Glucose Uptake
After eating food, glucose is released into
the blood. High concentrations of glucose will
cause the beta cells of the pancreas to release
insulin into the blood. Insulin will bind to the cell
membrane proteins to facilitate flow of glucose
into cells.
Diabetes
• Diabetes refers to a chronic disease where a
person has high blood sugar but the pancreas
does not produce enough insulin(Type I) or
cells cannot respond to the insulin produced
by the pancreas (Type II)
• Symptoms include weight loss. Frequent
urination, increased hunger/thirst, sometimes
blurred vision or skin rashes. Type I Diabetes
usually onsets more quickly than Type II
Diabetes
• An estimated 285 million people have
diabetes, 90% of which are Type II. Both types
of diabetes is more common in the western
world.
• No cure currently existing. Management
includes measuring and maintaining insulin
levels, insulin injections (especially in those
with Type I), and medications to combat
insulin resistance in those with Type II
diabetes.
Cushing’s Syndrome
• Cushing’s Syndrome refers to the symptoms
caused by abnormally high exposure to the
hormone cortisol. It can be onset by medicine
or a tumor on the pituitary gland (Cushing’s
disease)
• Symptoms include weight gain, moodiness,
weakness in the muscles, osteoporosis,
diabetes, hypertension, etc.
Cushing’s Syndrome
• Cushing’s syndrome is a relatively common
condition, it is usually caused as a side effect
of a steroid medication.
• The easiest treatment for Cushing’s is tapering
off of the causing medicine, or in the case of
Cushing’s Disease, removal of the causing
pituitary tumor.
Sources
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http://www.ama-assn.org/ama/pub/physician-resources/patient-education-materials/atlas-of-humanbody/endocrine-system.page
http://en.wikipedia.org/wiki/Endocrine_system
http://en.wikipedia.org/wiki/Homeostasis
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http://www.anewlife.co.uk/hormones_endocrine_glands.html
http://en.wikipedia.org/wiki/Oxytocin
http://en.wikipedia.org/wiki/Dopamine
http://en.wikipedia.org/wiki/Melatonin
http://en.wikipedia.org/wiki/Thyroxine
http://en.wikipedia.org/wiki/Insulin
http://en.wikipedia.org/wiki/Adrenaline
http://en.wikipedia.org/wiki/Testosterone
http://en.wikipedia.org/wiki/Progesterone
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http://en.wikipedia.org/wiki/Parathyroid_hormone
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http://www.livestrong.com/article/27924-insulin-signal-cell-glucose-blood/
http://en.wikipedia.org/wiki/Diabetes
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http://en.wikipedia.org/wiki/Cushing%27s_syndrome
http://en.wikipedia.org/wiki/Cushing%27s_disease