Download 29-6 Endocrine

Section 29-6
“Endocrine
System”
Write everything that is
underlined
29.6 The Endocrine System and Hormones
KEY CONCEPT
The endocrine system produces
hormones that affect growth,
development, and homeostasis.
29.6 The Endocrine System and Hormones
I. Hormones influence a cell’s activities
by entering the cell or binding to its
membrane
• Glands are
organs of the
endocrine
system
29.6 The Endocrine System and Hormones
• Hormones are chemicals:
– produced by glands
– travel through the circulatory system
(blood vessels)
– affects cells with matching receptors
target cell
hormone
bloodstream
receptor
not a target cell
29.6 The Endocrine System and Hormones
• There are steroid hormones and nonsteroid hormones.
– Steroid hormones enter the cell
– Nonsteroid hormones do not enter the cell
Steroid hormone
Steroid hormone
diffuses through the
cell membrane
Nonsteroid
hormone binds to
receptor on the
cell membrane.
Non-steroid
hormone
receptor
Steroid hormone
binds to a receptor
within the cell.
receptor
nucleus
The hormone and
receptor enter the
nucleus and bind
to DNA
DNA
Steroid hormone
causes DNA to
make proteins.
proteins
Receptor stimulates
a second messenger
with in the cell.
Second messenger
starts a series of
chemical reactions
in the cytoplasm.
Second messenger
reactions activate
enzymes.
second
messenger
Chemical
reactions
activated
enzymes
29.6 The Endocrine System and Hormones
Endocrine glands secrete hormones that act
throughout the body
• There are many glands in the body
HYPOTHALAMUS
PITUITARY
THYROID
THYMUS
ADRENAL GLANDS
PANCREAS
FEMALE GONADS
:OVARIES
MALE GONADS : TESTES
– Hormones travel through the bloodstream to
cells with matching receptors
29.6 The Endocrine System and Hormones
The hypothalamus interacts with the nervous and
endocrine systems
• The hypothalamus is a gland found in the brain
– a structure of both the nervous and
endocrine systems
– produces releasing hormones,
sent to pituitary gland
• The pituitary gland is found below
the hypothalamus in the brain.
– controls growth and water
levels in blood
– produces releasing hormones
sent throughout the body
–Here’s how
temperature
regulation occurs
by glands
communicating
with each other
29.6 The Endocrine System and Hormones
Hormonal imbalances can cause
severe illness
• Abnormal hormone levels affect
homeostasis
• Hormonal imbalances might be
treated with surgery or medicine
• Steroids, a pituitary tumor, or some
prescription drugs can make the
pituitary overactive and indirectly
cause problems