Download The Endocrine System

The Endocrine System
By:
Imani Elston and Kristin Hildreth
Period 5
What is the Endocrine System?
• Bodily system comprised of glands and
hormones
• Purpose: Regulate bodily functions
– Maintain homeostasis
– Regulate growth and development
– Respond to external factors (outside of the
body)
– Coordinate the production, use, and storage
of energy
What are Glands?
• A gland is a group of cells that produce
and secrete hormones either directly into
the bloodstream or extracellular fluid
The Hypothalamus and Pituitary
Gland
• The hypothalamus links the activities of the
nervous system and the endocrine system
– Receives information about internal and external
conditions from other cerebral regions
– Regulates bodily functions like body temperature
– Issues instructions to the pituitary gland
• The pituitary gland secretes hormones that
control other endocrine glands
– Divided into two lobes: anterior and posterior
– Aids in bodily functions, like the development of
gametes
The Thyroid and Parathyroid
Glands
• The thyroid gland makes and releases
thyroid hormones
– Regulates metabolism and promote the
growth of bones, muscles, and the brain
during childhood
– Maintains mental alertness in adults and
affects reproductive functions
• The parathyroid gland produces the
parathyroid hormone
– Raises the body's calcium levels
The Adrenal Glands
• Two almond-sized glands, one on top of each
kidney
• Adrenal medulla is a warning system in time of
stress by releasing "fight-or-flight" hormones
(epinephrine and norepinephrine)
– Prepare the body for action in emergencies
• Adrenal cortex produces hormones that give a
slower, long-term response to stress
– Cortisol: Makes more energy available to the body
– Aldosterone: Reabsorbs sodium ions from kidney
filtrate
What are Hormones?
• A hormone is a chemical compound that is
secreted by cells to regulate the activity of other
cells (chemical messengers)
– Two types:
• Amino-acid-based: Hormones made of amino acids (watersoluble)
• Steroid: Lipid hormones made from cholesterol (fat-soluble)
• Hormones bind and act on target cells
– Specific cell with certain receptors on surface or in
cytoplasm of cell
– Proteins are shaped to allow only one hormone to fit
Insulin and Adrenaline
• Insulin is a hormone that is secreted from the
pancreas
– Lowers glucose levels in the blood by promoting the
accumulation of glycogen, a polysaccharide, in the
liver
– Stimulates muscle cells to convert glucose into
glycogen
• Adrenaline (epinephrine) is a hormone made
in the adrenal glands
– Increases heart rate, blood pressure, cardiac output,
and metabolism
Calcitonin and Human Growth
Hormone
• Calcitonin is a hormone secreted from the
thyroid gland
– Is involved in the regulation of calcium levels in
animals by stopping the loss of calcium from bone to
the blood
• Growth Hormone is produced in the pituitary
gland
– Stimulates protein synthesis as well as bone and
muscle growth
– Encourages cell division
Estrogen and Testosterone
(Sex Hormones)
• The ovaries produce estrogen in females
– Estrogen is used to develop and maintain female sex
characteristics
– Prepares the uterus for fertilization of an egg
• Testosterone is produced in the testes in males
– The sex hormone that stimulates the development of
male sex organs, sexual traits, and sperm
Other Organs and Diseases
• Other organs and glands produce hormones, they
include:
– Stomach, small intestine, kidney, liver, pancreas
Diseases/Disorders:
• Overproduction of thyroid hormones (hypothyroidism)
can cause nervousness, sleep disorders, and an
irregular heart rate
– Daily use of synthetic thyroid hormone levothyroxine (Restores
hormone levels)
• Diabetes mellitus causes cells to be unable to obtain
glucose from the blood
– Result: High glucose levels
– Solution: Insulin injections, proper dieting and exercising
Bibliography
• Dowshen, Steven, MD. "Endocrine System: Body
Basics." Kidshealth.org. The Nemours Foundations, Mar.
2012. Web. 12 May 2013.
<http://kidshealth.org/teen/your_body/body_basics/endo
crine.html>.
• Johnson, George B., Ph.D., and Peter H. Raven, Ph.D.
Biology. Austin: Holt, Rinehart and Winston, 2007. Print.
(textbook)
• Rogers, Kirsteen, Verinder Bhachu, and Joanne Kirkby.
The Usborne Science Encyclopedia. London: Usborne,
2009. Print.