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Endocrine System
Hormones
AP Biology
2007-2008
Regulation
 Why are hormones needed?
chemical messages from one
body part to another
 communication needed to
coordinate whole body
 daily homeostasis & regulation
of large scale changes

 solute levels in blood
 glucose, Ca++, salts, etc.
 metabolism
 growth
 development
 maturation
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 reproduction
growth hormones
Regulation & Communication
 Animals rely on 2 systems for regulation

_______________________
 system of ductless glands
 secrete chemical signals directly into blood
 chemical travels to target tissue
 target cells have receptor proteins
 slow, long-lasting response

_______________________
 system of neurons
 transmits “electrical” signal &
release neurotransmitters to
target tissue
 fast, short-lasting response
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Regulation by chemical messengers
 _____________________ released by neurons
 _______________ release by endocrine glands
endocrine gland
neurotransmitter
axon
hormone
carried by blood
receptor proteins
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receptor proteins
target cell
Classes of Hormones
 ___________________________

polypeptides
 small proteins: ________, _________

insulin
glycoproteins
 large proteins + carbohydrate: ______, _______

amines
 modified amino acids: ___________, __________
 ___________________________

steroids
 modified cholesterol: _____________, __________
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How do hormones act on target cells
 _______________________________

__________________ & lipid-soluble
 diffuse across cell membrane & enter cells
 bind to receptor proteins in cytoplasm & nucleus
 bind to DNA as ________________________
 _______________________________
 _______________________________

__________________ & not lipid soluble




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can’t diffuse across cell membrane
bind to receptor proteins in cell membrane
trigger ________________________________
activate internal cellular response
 enzyme action, uptake or secretion of molecules…
Action of lipid (steroid) hormones
steroid hormone
target cell
S
1
S
cross cell membrane
S
cytoplasm
blood
protein
carrier
2
binds to receptor protein
becomes
transcription factor
5
S
3
mRNA read by ribosome
plasma membrane
DNA
4
mRNA
nucleus
6
protein
7
protein secreted
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ex: secreted protein = growth factor (hair, bone, muscle, gametes)
signal-transduction pathway
Action of protein hormones
1
protein
hormone
P
signal
plasma membrane
binds to receptor protein
activates
G-protein
activates enzyme
cAM
P
receptor
protein
activates
cytoplasmic
signal
GTP
cytoplasm
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target
cell
acts as 2° messenger
transduction
ATP
ATP
activates
enzyme
2
secondary
messenger
system
activates
enzyme
produces an action
3
response
Ex: Action of epinephrine (adrenalin)
adrenal gland
signal
1
epinephrine
activates
G protein
receptor
protein
in cell
membrane
activates GTP
3
activates
adenylyl cyclase
cAMP
GDP
transduction
4
GTP
2
ATP
activates
protein kinase-A
5
activates
phosphorylase kinase
cytoplasm
liver cell
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released
to blood
activates
glycogen phosphorylase
glycogen
6
glucose
7
response
Benefits of a 2° messenger
system1
signal
Activated adenylyl cyclase
receptor protein
2
Not yet
activated
amplification
4
3
GTP
amplification
cAMP
amplification
5
G protein
protein kinase
6
amplification
Amplification!
enzyme
Cascade multiplier!
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FAST
response!
7
amplification
product
Maintaining homeostasis
hormone 1
lowers
body condition
gland
high
specific body condition
low
raises
body condition
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gland
hormone 2
Negative Feedback
Model
Nervous System Control
Feedback
Controlling Body Temperature
nerve signals
sweat
high
body temperature
(37°C)
low
constricts surface shiver
blood vessels
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nerve signals
dilates surface
blood vessels
Endocrine System Control
Regulation of Blood Sugar
insulin
Feedback
islets of Langerhans
beta islet cells
body
cells take
up sugar
from blood
liver stores
glycogen
high
blood sugar level
(90mg/100ml)
low
triggers
hunger
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liver
releases
glucose
glucagon
islets of Langerhans
alpha islet cells
reduces
appetite
Endocrine System Control
Blood Osmolarity
osmoreceptors in
hypothalamus
Feedback
ADH
increased
water
reabsorption
increase
thirst
high
blood osmolarity
blood pressure
low
increased
water & salt
reabsorption
JuxtaGlomerular
Apparatus
renin
aldosterone
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angiotensinogen
angiotensin
Nervous & Endocrine systems linked
 ________________ = “master control center”



_______________________
receives information from nerves around body
about internal conditions
regulates release of hormones from pituitary
 ________________ = “master gland”


_________________________
secretes broad range
of hormones
regulating other
glands
hypothalamus
anterior
pituitary
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posterior
tropic hormones = target endocrine glands
Hypothalamus
thyroid-stimulating
hormone
(TSH)
Thyroid gland
Adrenal
cortex
antidiuretic
posterior hormone
pituitary (ADH)
anterior
pituitary
gonadotropic
hormones:
folliclestimulating
hormone (FSH)
& luteinizing
hormone (LH)
Kidney
tubules
Muscles
of uterus
Melanocyte
in amphibian
Bone
and muscle
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Testis
Ovary
Mammary
glands
in mammals
Homology in hormones
What does this tell you about these hormones?
How could these hormones have different effects?
same gene family
gene duplication?
prolactin
mammals
milk
production
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birds
fat
metabolism
fish
amphibians
salt &
water
balance
metamorphosis
& maturation
growth
hormone
growth
& development
Regulating metabolism
 Hypothalamus

_____ = _______________________
 Anterior Pituitary

_____ = _______________________
 Thyroid


produces _____________________
metabolism & development







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bone growth
mental development
metabolic use of energy
blood pressure & heart rate
muscle tone
digestion
reproduction
tyrosine
+
iodine
thyroxines
Goiter
Iodine deficiency causes thyroid to enlarge as it
tries to produce thyroxine
tyrosine
+
APiodine
Biology
thyroxines
Endocrine System Control
Feedback
Regulation of Blood Calcium
calcitonin
 kidney
reabsorption
of Ca++
thyroid
Ca++ deposited
in bones
high
blood calcium level
 Ca++ uptake
in intestines
(10 mg/100mL)
low
activated Vitamin D
bones
release Ca++
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 kidney
reabsorption
of Ca++
parathyroid
parathyroid hormone (PTH)
Feedback
Female reproductive cycle
egg
matures &
is released
(ovulation)
estrogen
builds up
uterus lining
corpus
luteum
ovary
progesterone
FSH & LH
maintains
uterus lining
pituitary
gland
hCG
yes
pregnancy
GnRH
hypothalamus
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fertilized egg
(zygote)
no
corpus luteum breaks down
progesterone drops
menstruation
corpus
luteum
progesterone
maintains
uterus lining
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Any Questions??
Robert Wadlow
1918-1940
8' 11"
AP Biology
2007-2008