crin (to
secrete)
dieuret-(to
pass urine)
endo-(within)
exo-(outside)
Hyper-(above)
Hypo-(below)
Para-(beside)
Toc-(birth)
-
Sarah


Helps regulate
conditions within the
body to maintain
homeostasis
Secretes hormones in
the body’s internal
environment

Works with the
nervous system so
that different parts of
the body can
communicate with
each other and
adjust to changing
incoming signals

Secrete substances
outside the body
through tubes or
ducts; leading to the
surface

endocrine

Secrete within the body
EX: pituitary gland

exocrine

Secrete to the outside of the body
EX: sweat gland
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Hormones are substance(s)
that are secreted by
endocrine glands and
transported into the blood
Hormones influence their
target cells during
stimulation
A hormone alters the
metabolism of the target
cells
*Paracrine: secretions
affect only neighboring
cells
*Autocrine: secretions
affect only secreting cell
1


2
Hypothalamus
regulates anterior
pituitary gland’s
release of hormones
that stimulate other
endocrine glands to
secrete hormones.
Hypothalamus
receives information
about the internal
environment from
neural connections
and cerebrospinal
fluid


Nervous system
stimulates glands
directly
A group of glands
responds directly to
changes in the
composition of the
internal environment

Only target cells can respond to a
hormone, they have a specific
receptor that other cells lack such
as proteins or glycoprotein (these
can bind with a hormone)
Endocrine and
nervous system
“oversee” the cell- tocell communication
through chemical
signals that bind
receptors to
molecules
Endocrine glands and
hormones
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
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Help maintain metabolic
processes
Control rate of reactions
Help transport substances across
membranes
Helps with water balance
Helps with electrolyte balance
Sierra
Hormones can produce
change in the target cell,
even at low
concentrations.
Steroids are carried through
the bloodstream and are
weakly bound to plasma
proteins, so they can be
efficiently released to their
target cells.
3
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1.
2.
3.
4.
5.
When a steroid hormone enters a target cell:
The steroid hormone diffuses through the cell
membrane
Then binds to a specific protein molecule-the
receptor for the hormone
The resulting hormone-receptor complex binds in
the nucleus to particular regions of the target cell’s
DNA and copies genes into the mRNA molecules
mRNA molecules leave the nucleus and enter
cytoplasm
mRNA molecules and the ribosome direct the
synthesis of specific proteins
The receptors are protein
molecules that have a
binding and activity site
Messages are sent to the
target cell by joining the
binding site of it’s
receptor (hormones
sending the message)
This stimulates the
receptor’s activity site to
interact with other
membrane proteins
Nonsteroid hormones
First
messenger
Receptor binding can alter
functions of enzymes or
membrane transport
mechanisms, which changes
concentration of other
cellular components
Nonsteroid hormones
Biochemicals
in cells that
produce
changes in
response to
hormone
building
The process of
chemical
communication from
the outside to the inside
of the cell
Is called
Is called
Second
messenger
Signal
transduction
The second messenger
associated with one group
of hormones is cyclic
adenosine monophosphate
(cyclic AMP)
It works like
this
4
cAMP activates
protein kinases
enzymes that
transfer phosphate
groups from ATP to
their substrate
molecules(specific
proteins)
Adenylate cyclase
catalyses the
circulation of ATP in
cytoplasm into
cAMP
Hormone
binds to its
receptor
Resulting
hormone
-receptor
activates
aG
protein
5
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

Group of
biochemicals that
regulate cells
Lipids from a fatty
acid in cell
membranes called
arachidonic acid
Usually only affect
the organs where
they are produced



Influence
movements of
sodium ions and
water molecules in
the kidneys
Helps regulate blood
pressure
Produced in many
cells





6
Hormone level rises
in the blood, the
hormone does its
effect.
The negative
feedback inhibits the
system and the
hormone secretion
decreases.
As the hormone
level decreases, the
effects of the
hormone stop.
When inhibition of
the system is lifted,
secretion of the
hormone takes
place once again.
Negative feedback
systems keeps
hormone levels in
the bloodstream
relatively stable.
Major endocrine glands!!!!
S
h
e
l
b
y
Attached to the
base of the brain
and has an anterior
and posterior lobe.
Releases hormones
from the
hypothalamus,
which controls the
secretions of the
anterior lobe.
Posterior lobe
releases hormones
into the
bloodstream in
response to nerve
impulses from
hypothalamus.
7
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8
Growth hormone(GH): stimulates body cells to grow and reproduce,
and speeds up rate at which cells use carbohydrates and fats
Prolactin(PRL): promotes milk production following the birth of an
infant
Thyroid-stimulating hormone(TSH): controls secretion of hormones
from thyroid gland
Thyrotropin-releasing hormone(TRH): from the hypothalamus
regulates release of TSH
Adrenocorticotropic hormone (ACTH): controls secretion of
hormones from adrenal cortex
Corticotropin-releasing hormone (CRH): regulates ACTH from the
hypothalamus, stress can also increase it’s release
Follicle-stimulating hormone (FSH): gonadotropins affecting male and
female gonads
Luteinizing hormone (LH): gonadotropins affecting male and female
gonads
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Neurons in the hypothalamus produce
antidiuretic hormone and oxytocin
ADH causes kidneys to conserve water
Hypothalamus regulates ADH secretion
based on the amount of water in body
fluids
Oxytocin plays a role in childbirth by
contracting muscles from uterine wall, and
forcing milk into ducts from milk glands
Stretching of the uterus in later stages of
pregnancy stimulates the release of
oxytocin
9
10
Located
below
 the
larynx and
consists of 2
lobes

Hypothalamus
and pituitary
gland control
release of these
Thyroxin
tetraiodothyronine
These 2
increase
the rate
at which
Cells release energy
from carbohydrates,
enhance protein
synthesis, and stimulate
breakdown of lipids
Extrafollicular cells of thyroid
secrete calcitonin
This lowers blood
levels of calcium
and phosphate
ions when they are
too high
Calcitonin secretion
is regulated by
negative feedback
involving blood
concentrations of
calcium
Calcitonin
increases
the rate at
which
calcium is
stored in
bones and
excreted
by urine
11
Located on
posterior end of
thyroid
PTH stimulates
bone
reabsorption by
osteoclasts,
releasing
calcium into
blood
*Calcitonin and PTH
exert opposite
effects in regulating
calcium ion levels in
blood
PTH
influences
kidneys to
conserve
calcium
Parathyroid
hormone(PTH)
increases blood
calcium ion
concentration and
decreases
phosphate ion
concentration
A negative feedback
mechanism involving blood
calcium levels regulates
release of PTH
Adrenal medulla: secretes epinephrine and norepinephrine
into the bloodstream(used in times of “fight or flight”)
Adrenal cortex: produces over 30 steroids
o Aldosterone: (mineralocorticoid) causes kidneys to
conserve sodium ions and thus water, and excrete
potassium ions
o Cortisol: (glucocorticoid) influences metabolism of
glucose, protein, and fat in response to conditions that
stress the body
o Adrenal sex hormones: released by the gonads and may
stimulate early development of reproductive organs
12
13
Posterior to stomach
Has 2 cell types:
Alpha cells: secrete glucagon
-glucagon increases the blood levels of glucose by
stimulating the breakdown of glycogen and
conversion of noncarbohydrates into glucose
Beta cells: secrete insulin
-insulin decreases the blood levels of glucose by
stimulating the liver to form glycogen, increasing
protein synthesis, and stimulating adipose cells to
store fat
*insulin and glucagon coordinate to maintain a
relatively stable blood glucose concentration
Pineal gland: lies near the
upper portion of the thalamus,
and secretes melatonin which
is involved in regulation of
circadian rhythms
-also linked to the onset of
puberty
Produces
atrial
natriuretic
peptide
Thymus gland: lies between
lungs and sternum, secretes
thymosins that affect
production of T lymphocytes
 ovaries produce estrogen
 Placenta produces
estrogen, progesterone, and
gonadotropin
 Testes produce testosterone
Kidney
produces
erythropoietin