Download The Endocrine System

Anatomy & Physiology 2



The endocrine system is
the chemical control of
your body (aka
hormones)
Endocrine glands are
found throughout the
body
Hormones are chemicals
that are made in one
part of the body and
affect another part of
the body

Two types: amino acidbased molecules or
steroids
 Hormones
affects
target only certain
tissues or organs –
called target cells
or target tissues
 The target cell or
target tissue has a
specific proteins
that allows the
hormone to attach
to
 Negative
feedback
mechanisms in the
blood are the
primary means of
controlling
hormones
 This occurs three
ways

Hormonal stimulus:
hormones trigger by
other hormones; most
“triggers” start in the
hypothalamus in the
brain
 This
occurs three
ways, continued:
Humoral stimuli :
fluids in the blood
cause the release ,
example is the
production of insulin
 Neural stimuli: nerve
fibers trigger the
release, example is
adrenaline

 Major
organs
include:
Pituitary, thyroid,
parathyroid, adrenal,
pinal, thymus,
pancreas and gonads
 Hypothalamus is part
of the nervous
system, but also
considered part of the
endocrine as well

 Pituitary Gland
 Located in the brain and
approximately the size of
a grape
 Called the master gland
because it makes
hormones that regulate
other glands
 Causes people to grow
and onset of puberty
 Produces: tropic, growth,
prolactin,
adrenocorticotropic,
thyroid-stimulating,
thyrotropic,
gonadotropic, folliclestimulating, lueteinizing,
and interstitial cellstimulating hormones
 Thyroid Gland
 Found in your lower
neck by the wind pipe
 Regulates your
metabolism
 Parathyroid


Glands
Two lobes found
near the thyroid
gland
Help control blood
calcium levels and
calcium absorption
 Adrenal


glands
Found over the top
of the kidneys
Helps to regulate
mineral absorption,
helps regulate blood
pressure, helps
regulate blood sugar
and produces some
sex hormones
 Pancreas


Produces insulin,
which regulates
blood sugar
If there is too much
sugar in the blood in
pushes the sugar
out of the blood; if
there is too little
causes stored sugars
to be releases
 Pinal



gland
Found in the brain
Not much is known
about this gland,
but the “sleep
trigger” appears to
be here
It also appears to
inhibit sexual
maturation until an
adult size body is
reached
 Thymus



Located in the
upper throat
Large in infants and
children, but
decreases in size as
we age
Helps with growth
and immunity
 Gonads

Female gonads:
ovaries



Almond-sized and
located in the pelvic
cavity
Produce estrogen and
progesterone
The rhythmic cycle of
these two hormones
cause the release of
the ova and the
secondary sex
characteristics in
females
 Gonads

Male gonads: testes



Located outside the
body in the scrotum
Produce androgens,
which testosterone is
the most important
Testosterone cause
the production of
sperm and male sex
characterisitics
 Placenta
A temporary organ
found in the uterus
only during pregnancy
 Provides respiratory,
excretory and
nutrition delivery for
the growing fetus, but
also produces
hormones necessary
to maintain the
pregnancy

 Placenta
Produces human
chorionic
gonadotropin (hCG)
hormone – this is what
home pregnancy tests
detect
 Also produces human
placental lactogen to
prepare breasts for
lactation
 Also produces relaxin
to loosen ligaments
for childbirth

 Diabetes
mellitus
 Goiters
 Graves’
 Tumors
disease