The Endocrine System
The Endocrine System
• Endocrine’s latin parts mean inside secretion
• DEFINITION: the endocrine system is a system of
ductless glands that secrete hormones directly
into the bloodstream or lymph system for a
specific physiological purpose or response
• The endocrine system is responsible for:
– male and female differentiation (during puberty and
in the womb)
– flight or fight response
– sleep regulation
– cellular metabolism
– disease defense
– energy regulation
– reproduction
• All of the processes are controlled by the
chemicals released from the glands called
HORMONES
The organs of the endocrine system are spread throughout the body
Two types of hormone
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Protein-like Hormones
Made of amino acids, just
like proteins
Can be very large in size
Are water soluble
Need receptors to pass
through the fatty cell
membrane
Ex: insulin
Fat-based Hormones
• Also called steroids
• Don’t dissolve in water or
plasma (blood)
• Need transport proteins to
move through the blood
stream
• Pass easily through the fatty
cell membrane
• Ex: cortisone, estrogen,
testosterone
Testosterone entering a target cell
Percy Julian
(1899-1975)
-entered university at a time
and place where public
education for AfricanAmericans only went up to the
8th grade
-used soy sterol to manufacture
progesterone and testosterone,
useful for troubled pregnancies,
and a significant step forward in
creating oral birth control
-invented a synthetic cortisone
substitute that is used to treat
arthritis
Hormones Activity
• Each lab group will be assigned a hormone. Your job is to figure out:
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Where the hormone is produced (what organ or type of cell?)
What initiates release and/or production of the hormone
The target cell type for the hormone
The effect of this hormone on the target cell(s)
How the release of the hormone is regulated
How the hormone travels through the body and into the cells
• You will present this information to your classmates utilizing the
organs scattered around the room to show the cycle of the
hormone, from stimulation of production to regulation of level
• Signs and role-playing of different hormones or other signalers is
mandatory!
Types of Steroid Hormones and How They Are Produced