Endocrine System

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Endocrine System
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Aim What are the main parts and functions of the
endocrine system?
I. Endocrine System
A. Endocrine (ductless) gland - is a group of
cells that produces and secretes chemicals. A
gland selects and removes materials from the
blood, processes them, and secretes the finished
chemical product for use somewhere in the body.
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NO DUCTS
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Exocrine gland a gland that has a duct and
releases it secretions directly to where they
have to go. Ex pancreatic duct and bile duct.
DUCTS
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B. Hormone - is a chemical messenger from one
cell to another.
C. Target Cell specific cell that a specific
hormone stimulates.

• A target cell may do one of the following when
  stimulated by a hormone
• Secrete more of its product
• Stop secreting its product

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II. Main endocrine glands
A. Hypothalamus links the nervous system to the
endocrine system. Releases hormones that go to
the pituitary gland and tells the pituitary what
hormones to secrete.
B. Pituitary Gland Master Gland produces
hormones that affect many other endocrine glands.
1. Has two lobes (anterior and posterior) that
release their own hormones.
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2. Hormones of the pituitary
a. Growth hormone (GH) controls growth by
promoting growth of bone and muscle.
Robert Wadlow
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b. Thyroid stimulating hormone (TSH) stimulates
thyroid gland to release thyroxin.
c. Follicle stimulating hormone (FSH)
stimulates the follicles in females to develop
egg.
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C. Thyroid Gland releases thyroxin which
controls rate of metabolism.
Goiter
Results from having insufficient iodine in diet.
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D. Islets of Langerhans found in the pancreas.
Release hormones insulin and glucagon.

1. Insulin lowers blood sugar level
2. Glucagon raises blood sugar level.

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E. Adrenal Glands located on top of kidneys.
Secrete hormones adrenaline (epinephrine) and
noradrenaline (norepinephrine).
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1. Adrenaline is the fight or flight hormone.
F. Gonads testes and ovaries.
1. Testes secrete hormone testosterone that is
responsible for secondary sex characteristics.
2. Ovaries secrete hormones estrogen and
progesterone. These hormones are responsible for
secondary sex characteristics and the menstrual
cycle.