The
Endocrine System
By Jonathan Gonzalez, Aaron Mednick, Matt Solórzano,
Grant Zitomer
What Does It Mean?
• Endo: within
• Crinis: secrete
Opposed to exocrine system, which
excretes substances into external
environment such as sweat and saliva
Physiology
• Releasing hormones into bloodstream
• Many organs and glands work in tandem
• Functions:
o Controlling internal chemical environment
o Responding to change in case of emergency
(i.e. infection)
o Regulating metabolism and energy balance
o Contributing to growth and development
Important Glands and Organs
• Hypothalamus: part of brain, secretes
hormones; controls homeostasis
• Pineal Body/Gland: produces melatonin
•
•
•
(helps regulate circadian rhythm [i.e.
sleep])
Pituitary Gland: regulates all endocrine
gland functions
Thyroid Gland: important for regulating
metabolism
Ovaries: produce egg cells, estrogen, and
Important Glands and Organs, cont'd
• Parathyroid Glands: regulate body
calcium balance
• Thymus: trains T-Lymphocytes (WBC)
• Adrenal Glands: produce and release
adrenaline & cortisol responding to stress
• Kidneys: process blood to filter out waste
products
• Pancreas: assists in digestion and
hormone production
• Testes: produce testosterone and sperm
Hypothalamus
• Located within the brain near optic chiasm
• Secretes hormones which control anterior
pituitary
• Controls:
o Water Balance
o Sleep
o Temperature
o Appetite
o Blood Pressure
Hypothalamus, cont'd
• Releases into the pituitary gland
o Dopamine
o Thyrotropin-releasing hormone
o Corticotropin-releasing hormone
o Gonadotropin-releasing hormone
o Growth hormone-releasing hormone
o Somatostatin
Pituitary Gland
• Not part of the brain, but protrudes off of
hypothalamus
• Controls:
o Growth
o Sex organs
o Metabolism
o Water balance
o Temperature
Pituitary Gland, cont'd
• Prolactin
o Stimulates mammary glands
o Causes sexual arousal
• Thyrotropin
o Stimulates thyroid
• Growth hormone
o Stimulates development and growth
Pineal Body/Gland
• Located in the brain
• Produces melatonin that affects:
o Sleep/wake patterns
o Seasonal functions
Thyroid Gland
• Located below the Adam's Apple in the
neck
• Controls metabolism
o How fast the body reacts to hormones
o Protein production rate
o Energy usage speed
Thyroid Gland, cont'd
• Thyroid stimulating hormone (TSH)
activates:
o Triiodothyronine (T3) which controls
 Body temperature
 Heart rate
 Growth
•
o Thyroxine (T4) which controls
 Rate of protein synthesis
 Growth
 Produces ATP from glucose
These two hormones affect almost all physiological
processes in the body
Parathyroid Glands
• Located behind to the thyroid gland
• Regulates all calcium in the body
o Calcium is the only mineral that has its own
regulatory system.
• Provides electrical energy to muscles and
•
nervous system
(via calcium regulation)
Provides strength to
skeletal system
(via calcium regulation)
Parathyroid Glands, cont'd
• Produces Parathormone
o Increases concentration of calcium in blood
o Stimulates osteoclasts
o Increases calcium reabsorption in kidneys
(to the bloodstream)
• Produces Calcitonin
o decreases concentration of calcium in blood
o Inhibits osteoclast activity in bones
o Increases amount of calcium in urine
Thymus
• Trains T-Lymphocytes (also known as TCells)
• Part of immune system as well
• Part of endocrine for use of hormones in
training
Adrenal (Suprarenal) Glands
• Located superior to both kidneys
• Responsible for releasing hormones in
response to stress
o Cortisol: stress and low glucose
o Epinephrine: "fight or flight"
• Produce androgen
o Controls and maintains
development of male
characteristics in vertebrates
(primary androgen is testosterone)
Adrenal Glands, cont'd
• Produce aldosterone
o Increase reabsorption of water in kidney
o Results in increased blood pressure
Kidneys
• A natural "filter" for the endocrine system
• Processes the blood to sift out waste
products and extra water
o Waste and extra water is excreted as urine
Pancreas
• A dual function organ
• Produces several important hormones
o Insulin: lowers blood glucose levels
o Glucagon: raises blood glucose levels
• Also secretes digestive enzymes which
assist the stomach
Ovaries
• Located in groin area of females
• Produces:
o Egg Cells (for reproduction)
o Estrogen
o Progesterone: the "pregnancy hormone"
Estrogen
• Develops secondary female
characteristics
o Enlargement of breasts
o Widening of hips
o Growth of pubic hair
• Regulates menstruation
Progesterone
• Effects:
o Prepares uterus for implantation
o Makes vaginal skin impenetrable to sperm
o Decreased levels lead to:
 Menstruation if not pregnant
 Labor if pregnant
Testes/Testicles
• Located in groin area of males
• Produces:
o Testosterone: develops male reproductive
tissues; increases muscle mass
o Sperm: fuse with egg cells during fertilization
Testosterone
• Develops secondary male characteristics
o Body hair
o Facial hair
o Muscle growth
o Deepens voice
o Adam's Apple
o Sperm creation
Disorders
• Occur due to the increase or decrease of
endocrine hormones, which may be
caused by:
o Problems with endocrine feedback
o Failure of a gland to stimulate another gland
to release its hormone
o Genetics
o Infection
o Injury to an endocrine gland
Adrenal Insufficiency
• The adrenal glands do not release
•
enough cortisol and sometimes
aldosterone
Symptoms:
o Muscle weakness, loss of appetite, weight
loss
o Nausea, vomiting, diarrhea, headache,
sweating
o Low blood pressure, low blood glucose
Hyper/Hypothyroidism
• Hyperthyroidism
o High heart rate
o Tremors
o Weight loss
• Hypothyroidism
o Low heart rate
o Fatigue
o Weight gain
o Growth stunting
Gigantism and Acromegaly
• Caused by the secretion of excess growth
hormone from the pituitary gland
o Gigantism: during childhood
o Acromegaly: during adulthood
• Usually tumors in the gland
cause these disorders
Multiple Endocrine Neoplasia
(MEN)
• Rare genetic disorder
• Causes tumors which cause
overproduction in affected glands:
o Parathyroid
o Adrenal
o Thyroid
Testing for Disorders
• Visit an Endocrinologist:
o Conduct urine and blood tests
o Imagine test pinpoint tumors
o Check hormone levels
• Treatment
o Difficult because complication with one
hormone balance affects other hormone
balances
o Routine blood work to track imbalance
Relationship Between Endocrine
System and Other Systems
•
•
•
•
•
•
Reproductive System - hormones control development
of reproductive organ; regulates production of gametes
Respiration System - hormones regulate breathing rate
Skeletal System - hormones regulate bone growth/
calcium concentration
Muscular System - hormones regulate muscle
metabolism
Excretory System - hormones control water
conservation in kidneys
Immune System - parathyroid regulates calcium levels;
cortisol can be used as an immunosuppressant
To Recap...
• Regulates homeostasis
• Is in control of the body's hormones
• These hormones tell many things in the
body what to do, from growing to
breathing to giving birth
So remember to thank your
endocrine system
Works Cited
http://www.medterms.com/script/main/art.asp?articlekey=3791
http://www.britannica.com/EBchecked/topic/118220/circadian-rhythm
http://www.britannica.com/EBchecked/topic/460967/pineal-gland
http://www.medterms.com/script/main/art.asp?articlekey=3791
http://www.yourhormones.info/hormones/calcitonin.aspx
http://www.britannica.com/EBchecked/topic/186893/human-endocrine-system
http://www.nlm.nih.gov/medlineplus/ency/article/001174.htm
http://women.webmd.com/guide/understanding-thyroid-problems-basics
http://www.webmd.com/digestive-disorders/picture-of-the-pancreas
http://www.britannica.com/EBchecked/topic/435788/ovary
http://www.nlm.nih.gov/medlineplus/ency/article/002380.htm
http://www.hormone.org/Pituitary/overview.cfm