Lecture 4 - 2/18/10 Diabetes 
 •  Overview
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Unformatted text preview: 2/18/10 Diabetes 
 •  Overview
Video
 Chapter
17
 The
Endocrine
System
 The
Endocrine
System
 The
endocrine
system
is
built
quite
differently
than
other
 systems,
it
is
mainly
a
group
of
separate
structures
called
 endocrine
glands
 –  Also
some
organs
that
secrete
hormones
but
are
not
 considered
glands
 •  kidneys,
stomach,
liver,
skin,
ovaries/testes,
heart,
small
intesAnes
 The
endocrine
glands
and
the
hormone‐secreAng

 organs
and
Assues
together
 ‐
Connected
by
the
cardiovascular
system

 ‐
Tied
to
the
nervous
system
 An
endocrine
gland

 secretes
its
products

 directly
into
the

 bloodstream
 The
Endocrine
System
 Organs
and
Assues
communicate
with
cells
using
chemical
 messengers
called
hormones
 –  the
products
of
endocrine
glands
are
hormones
 –  hormones
get
to
almost
every
cell
in
the
body
 Hormones
are
chemically
acAve
compounds
that
are
produced
in
one
 area
of
the
body
but
have
their
effect
elsewhere

 –  cells
that
hormones
act
upon
are
target
cells
 –  sequenAal
changes
of
growth
and
maturaAon
 –  agents
of
response
when
homeostasis
is
disrupted
 Hormones
 The
two
main
classes
of
hormone
are
steroid
hormones
and
 nonsteroid
hormones
 –  the
main
difference
between
these
classes
is
solubility
 –  translates
into
completely
different
modes
of
acAon
 Steroid
hormones:
 
‐
lipid‐soluble
 
‐
testosterone
and
estrogen
 Nonsteroid
hormones:
 
‐
not
lipid‐soluble
 Hormones
 Hormones

 –  –  –  –  –  maintain
fluid
balance
 control
calcium
and
glucose
levels
in
the
blood
 assist
in
Assue
repair
 maintain
basal
metabolic
rate
 assist
in
digesAng
food
 The
acAon
of
a
hormone
is
enArely
dependent
on
the
target
cell,
so
a
 parAcular
hormone
can
have
widely
varying
effects
on
different
 Assues
 –  one
hormone
can
have
many
different
target
cells
 1 2/18/10 Nonsteroid
hormones
are
fast‐acAng
and
powerful
 Nonsteroid
Hormones
 Nonsteroid
Hormones
 Hormone binding to exterior of the integral protein activates the associated (inactivated) molecule, releasing it into the cytoplasm - the released molecule, usually cyclic AMP (cAMP), becomes a second messenger activates an enzyme (kinase) altering various biochemical and cellular pathways –  affect
target
cells
more
quickly
than
steroid
hormones
because
they
affect
the
 acAvity
of
proteins
that
are
already
present
 –  water‐soluble,
so
they
are
easily
transported
to
the
cell
in
blood
or
intersAAal
 fluid
 Nonsteroid
hormones
act
on
specific
receptors
that
stud
the
surface
of
 target
cells
 –  these
receptors
are
integral
membrane
proteins,
oJen
with
an
associated
but
 inacAve
molecule
aKached
to
the
cytoplasmic
side
of
the
protein
 Endocrine
Glands
and
Secre;on
 The
endocrine
glands
secrete
directly
into
the
bloodstream
 Hormones
usually
get
released
into
our
bloodstreams
in
short
bursts
 when
an
endocrine
gland
is
sAmulated
 –  When
sAmulaAon
stops,
concentraAon
of
hormone
in
blood
 drops
 –  this
negaAve
feedback
system
usually
ensures
that
the
hormone
 is
not
overproduced
or
underproduced
 The
endocrine
system
has
several
key
components
 –  Hypothalamus,
pituitary,
adrenal
glands,
thyroid,
parathyroid,
 Thymus,
pineal
gland,
pancreas
 The
Adrenal
Glands
 The
adrenal
glands,
atop
the
kidneys,
secrete
a
number
of
hormones
 The
cortex
secretes
glucocor;coids,
mineralocorAcoids,
and
small
amounts
of
 estrogen
and
testosterone
 The
adrenal
medulla
secretes
epinephrine
and
norepinephrine,
which
cause
 the
fight‐or‐flight
reacAon 
 GlucocorAcoids
are
a
group
of
hormones
involved
in
glucose
 metabolism
 –  the
glucocorAcoid
secreAon
of
the
adrenal
cortex
is
cor;sol
 •  corAsol
is
similar
to
glucagon
in
that
it
promotes
the
use
of
fats
 and
proteins
as
energy
sources
 •  Controlled
by
another
endocrine
gland
that
releases
ACTH
 •  ACTH
release
is
controlled
by
CRH
(corAsol‐releasing
hormone)
 which
is
released
from
yet
another
endocrine
gland
 –  as
ACTH
level
increases,
corAsol
is
produced

 –  rising
blood
levels
of
corAsol
inhibit
ACTH
and
CRH
 –  these
hormones
fluctuate
constantly
around
their
ideal,
 keeping
corAsol
levels
within
a
narrow
range
 Adrenal
Hormones
 2 2/18/10 The
Pancreas
 The
pancreas
plays
a
dual
role
 –  it
serves
as
an
exocrine
gland
that
secretes
digesAve
enzymes
 through
ducts

 –  it
secretes
a
number
of
endocrine

 hormones
involved

 in
maintaining

 blood
glucose

 levels
pancreas
 The
Pancreas
 The islets include alpha, beta, and delta cells: the alpha cells secrete glucagon - Why? Breakdown glycogen or protein - glucagon increases blood sugar between meals beta cells secrete insulin (opposes glucagon) -lowers blood sugar- How? -clears glucose from blood - if insulin fails, blood glucose levels will rise causing osmotic balance problems in all tissue Diabetes
mellitus:

 impairment
of
glucose
homeostasis
 –  body
loses
control
of
blood
blucose
 levels
 Diabetes
may
be
the
most
serious
chronic
 disease
in
the
United
States
 –  at
least
$92
billion
a
year
in
health
 care
costs
 –  ~7
percent
of
U.S.
populaAon
has
 diabetes
(including
6.2
million
people
 who
are
unaware)
 –  Diabetes
is
the
sixth
leading
cause
of
 death
in
the
United
States,
directly
or
 indirectly
causing
about
225,000
 deaths
per
year
 Diabetes
Mellitus
 Type
1
Diabetes
 –  “juvenile
diabetes”
 –  pancreas
suddenly
stops
making
funcAonal
insulin
 –  autoimmune
aKack
destroying
islet
cells
 –  paAent
must
take
over
the
normal
responsibiliAes
of
the
pancreaAc
islets,
 monitoring
the
level
of
glucose
in
the
blood
and
injecAng
insulin
when
it
climbs
 Diabetes
Mellitus
 Type
2
Diabetes
 –  usually
appears
during
adulthood
 –  paAent
has
some
insulin
but
maintains
an
excessive
level
of
blood
glucose
 –  cells
cease
responding
to
insulin:
insulin
resistance
 –  once
called
“adult‐onset
diabetes,”
(~90
percent
of
all
cases)
 –  in
some
cases,
the
beta
cells
also
fail
to
produce
enough
insulin
 –  even
if
the
blood
contains
an
abnormally
high
level
of
insulin,
the
cells
sAll
 cannot
absorb
glucose
properly
 –  seems
to
combine
geneAc
and
behavioral
components
 –  Strongly
associated
with
a
family
history
of
diabetes,
older
age,
obesity,
and
 lack
of
exercise
 –  it
is
more
common
in
women,
especially
those
with
a
history
of
gestaAonal
 diabetes
(diabetes
during
pregnancy),
and
among
Hispanic,
NaAve
American,
 and
African
American
populaAons
 Diabetes
Mellitus
 Regula;on
of
Blood
Glucose
 As
blood
glucose
levels
increase,
 insulin
producAon
is
sAmulated
 –  cells
of
the
body
pick
up
 blood
glucose
in
response
to
 insulin
 When
blood
glucose
levels
reach
a
 low,
glucagon
is
released
to
 restore
the
higher
blood
glucose
 level
 3 2/18/10 Chapter
16 
 The
Urinary
System 
 4 ...
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This note was uploaded on 10/27/2010 for the course BIOL 125 taught by Professor Klein during the Spring '10 term at CUNY Hunter.

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