Download 39.1-2 Endocrine System notes only

Vocabulary
Endocrine System
Chapter 39.1-2
I. 
Endocrine system = glands that
release their products into the
bloodstream to deliver messages
throughout the body
1. 
Pituitary gland
- produces hormones that
regulate many of the other
endocrine glands
endocrine = releases hormone
directly into blood stream (ex:
pancreas secretes insulin into
blood)
Parathyroid glands
- 4 glands release
parathyroid hormone, which
regulate calcium in the blood
2. 
B. 
exocrine = releases hormones on
the surface or into the body cavity
(ex: sweat glands)
Glands = organs that produce and
release hormones
1. 
2. 
3. 
Hypothalamus = part of the brain
which controls the pituitary
Pituitary gland = secretes 9
hormones that control the actions
of other glands
Thyroid gland = regulates
body s metabolism by
releasing thyroxine
a.  Hyperthyroidism = too
much thyroxine 
nervousness, increased
metabolic rate,
increased blood
pressure
b.  Hypothyroidism = too
little thyroxine  lower
metabolic rate, lower
body temperature, and
weight gain
4.  Parathyroid glands = on
the back of the thyroid,
assist in maintaining
calcium levels
exocrine gland
endocrine gland
pituitary gland
thyroid gland
adrenal glands
diabetes
gonads
ovaries
testes
hormone
target cell
prostaglandin
Hypothalamus
- makes hormones that
control the pituitary gland
Human Endocrine Glands
A. 
1. 
2. 
3. 
4. 
5. 
6. 
7. 
8. 
9. 
10. 
11. 
12. 
DRAW Figure
39-2, pg 998
with labels
Thymus
During childhood, stimulates
Tcell development
Adrenal glands
- release epinephrine and
nonepinephrine, which help the
body deal with stress
Pineal gland
- releases melatonin, which is
involved in rhythmic activities,
such as sleep-wake cycles
Thyroid
- produces thyroxine, which
regulates metabolism
Pancreas
- produces insulin which regulates
the level of glucose in the blood
Ovary
- produce estrogen, progesterone, &
eggs
Testis
- produce testosterone
& sperm
5.  Adrenal glands = release
hormones that help the body
deal with stress
a.  Adrenal cortex – regulates
sodium, potassium, and
metabolism of carbs, fats,
and proteins
b.  Adrenal medulla –
1)  produces epinephrine
(adrenaline), the fight or
flight response to stress
2)  general increase in body
activity in preparation for
intense physical activity
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6.  Pancreas
a.  helps regulate insulin and
glucagon to keep glucose
levels in the blood stable
b.  diabetes = when the
pancreas fails to produce
or properly use insulin
(high glucose levels can
damage most cells in the
body)
1)  Type I diabetes –
autoimmune disorder,
little or no secretion of
insulin, developed
before 15 years old
2)  Type II diabetes –
produce low insulin
but cells are unable to
properly respond to it,
can be controlled by
proper diet and
exercise
7.  Reproductive glands
a.  gonads = production of gametes and
secretion of sex hormones
1)  female gonads – ovaries which produce eggs,
estrogen, and progesterone
2)  male gonads – testes which produce sperm,
testosterone
Pituitary gland
Thyroid
Adrenal glands
Pancreas
Kidney
8. Endocrine System Graphic Organizer
Endocrine
System
regulates
Growth
Water
balance
by means
of the
by means
of the
Pituitary
Ovaries
II.
Hormones
A.  hormones = chemicals released in one part of
the body that travel through the bloodstream and
affect the activities of cells in other places
1.  target cells = cells that have receptors for a
particular hormone
2.  the body’s response to hormones is slower
and longer lasting than responses to nerves
Parathyroid
glands
Reproduction
Metabolism
by means
of the
by means
of the
Testes
Thyroid
Calcium
and glucose
levels
by means
of the
Pancreas
Response
to stress
by means
of the
Adrenals
Parathyroids
B.  Hormone action
1.  Steroid hormones
a.  produced from cholesterol (a lipid)
b.  can cross cell membranes, binds to DNA
c.  steroid hormones can turn on or off whole sets
of genes
2.  Nonsteroid hormones
a.  cannot pass through cell membrane, but binds to
cell membranes to affect cell activity
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C.  Prostaglandins
1.  produced by all cells in small amounts, only affect
nearby cells (“local hormones”)
2.  Ex: aspirin stops the production of a prostaglandin
which causes headaches
D. 
Endocrine Control
endocrine system is controlled by negative
feedback mechanisms to maintain homeostasis
2.  Metabolism control
1. 
a. 
b. 
c. 
thyroid makes thyroxine  increases metabolism
hypothalamus senses thyroxine is low  TRH released to
stimulate anterior pituitary  TSH released to stimulate the
thyroid to produce more thyroxine
high levels of thyroxine  decreases TRH and TSH which
stops the release of thryroxine
DRAW Figure 39-4, page 1000
Feedback Mechanism
Example - Rate of metabolism
When the hypothalamus senses
that the level of thyroxine in the
blood is low, it secretes TRH.
TRH stimulates the anterior
pituitary to secrete TSH. TSH
stimulates the thyroid to release
thyroxine. Increased levels of
TSH and thyroxine inhibit TRH
secretion by the hypothalamus.
3.  Water balance
a.  dehydration stimulates the release of ADH,
causing the kidneys to conserve water
b.  an oversupply of water causes the kidneys to
eliminate excess water in urine
4.  Complementary hormone action
a.  two hormones can work with opposite effects to
regulate homeostasis
b.  Ex: calcium
1)  blood calcium levels too high  calcitonin
released by parathyroid glands telling kidneys
to release more calcium in urine
2)  blood calcium levels too low  PTH released
telling intestine to absorb more calcium from
food
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