Endocrine System 2

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Transcript Endocrine System 2

The Endocrine System
What is the system?
1. Made up of glands that produce
and secrete hormones (chemical
2. Responsible for regulation of
growth, metabolism, sexual
3. Responses to stress and injury
4. Internal balance of
body systems (homeostasis)
• HORMONES are chemical
MESSENGERS that act on target cells (or
• Endocrine – secretions inside the body
• Exocrine – secretions outside the body
Major Structures
• Master Gland =
Pituitary Gland
• BUT…… the
controls the
actions of the
pituitary gland!
Pituitary Gland
Control of Hormone
Negative Feedback
• When hormone
levels rise, the
brain detects it
• Then, that gland is
shut off!!
Pituitary Gland
Prolactin (PRL)
Growth Hormone (GH)
Adrenocorticotropin (ACTH)
Thyroid Stimulating Hormone (TSH)
Luteinizing Hormone (LH)
Follicle Stimulating Hormone (FSH)
Oxytocin (OXY)
Antidiuretic Hormone (ADH)
-Color Denotes Posterior Pituitary Hormones
• Stimulates milk production from a
woman's breasts after childbirth
Growth Hormone
• Stimulates growth in childhood and is
important for maintaining a healthy body
• In adults it is also important for
maintaining muscle mass and bone mass.
It can affect fat
distribution in the body.
HGH and Controversy
• Human Growth Hormone can be
prescribed to treat growth disorders in
• Also currently used in U.S. livestock milk
production, deemed controvercial
• Athletes have been abusing this drug
since 1982 as it is an “anabolic” agent,
was impossible to detect difference in
blood test b/t natural and artificial until
• It is banned by the NCAA ,IOC, MLB,
NFL, etc
Problems with pituitary can
result in dwarfism- an
undersecretion of growth
Disproportionate Dwarfism:
Achondroplasia, genetic, affects more
than GH output
Or a person can grow too much!
These are pictures of the man known
as “The Alton Giant”, Robert Wadlow.
The video clip is of Andre the Giantwrestler/actor. He suffered from
acromegaly, an over secretion of GH
in adults (gigantism= over secretion of
GH in childhood)
• Stimulates production of cortisol by
the adrenal glands.
• Cortisol, a so-called "stress
hormone," is vital to survival. It helps
maintain blood pressure and blood
glucose levels.
Many diet aids claim that they
block cortisol levels. Cortisol
from stress may lead to fat
deposits in the belly.
Thyroid Stimulating
• Stimulates the thyroid gland to make
thyroid hormones, which, in turn,
control (regulate) the body's
metabolism, energy, growth and
development, and nervous system
Luteinizing/Follicle Stimulating
• LH regulates
testosterone in
men and estrogen
in women.
• FSH promotes
sperm production
in men and
stimulates the
ovaries to release
eggs (ovulate) in
• Causes milk letdown in nursing
mothers and contractions during
Antidiuretic Hormone
• Regulates water balance by increasing
retention of water
• Acts on the kidney (nephron)
• Also called “vasopressin”
– If not secreted properly, can lead to problems of
sodium (salt)/water balance
-polydipsia (excessive thirst)
» v
-polyuria (excessive urination)
-hypernatremia (excessive sodium)
Thyroid Gland
• The thyroid hormones
control your
metabolism, which is
the body's ability to
break down food and
store it as energy and
the ability to break
down food into waste
products with a
release of energy in
the process.
Thyroid Hormones
• Thyroxin (T4) &
(T3) - both
increase the rate
at which cells
release energy
• Calcitonin –
regulates the
concentration of
Thyroid Problems!!
• Thyroid hormone is partly made of iodine.
Iodine is essential for the formation of
thyroxin. If a person doesn’t eat enough
iodine, they can’t make thyroid hormone.
• So, the size of the follicle grows b/c there
is no hormone output (like an engine
running idle), the gland grows = GOITER.
• Iodine is only found in seafood, so if salt
wasn’t iodized, a lot of people wouldn’t get
enough iodine, and there would be a lot of
• Early symptoms:
• Being more sensitive to
• Constipation
• Depression
• Fatigue
• Heavier menstrual periods
• Joint or muscle pain
• Paleness or dry skin
• Thin, brittle hair
• Weakness
• Unintentional weight gain
• Condition in which
the thyroid gland
does not make
enough thyroid
Hypothyroidism: Before
and After Treatment
Cretinism (hypothyroidism in
Mild to severe infants)
impairment of both
physical and mental
growth and
• Thickened skin,
enlarged tongue, or
a protruding
• Almost completely
eliminated from
countries due to
newborn screening
Autoimmune Disease
• Antibody attacks thyroid and
mimics TSH
• Results in enlarged thyroid
and hyperthyroidism
• Fast heartbeat, sleep
disorder, muscle weakness,
exophthalmos, irritability
• Caused by genetic and
environmental factors
• Treatment: Anti-thyroid
drugs, radioiodine, or
Parathyroid Gland
• Located behind the
thyroid, four tiny glands
that help maintain
calcium and
phosphorous levels
• Parathyroid Hormone
(PTH) - takes calcium
from the bones to make
it available in the blood
Adrenal Glands
• Each adrenal gland is
actually 2 endocrine organs
located right above each
• The outer portion is called
the adrenal cortex.
• Makes hormones involved in
glucose and mineral
balance, anti-inflammatory
(long term stress response)
• The inner portion is called
the adrenal medulla.
• These hormones stimulate
the “Fight or Flight”
response (Short term stress
Medulla Hormones
• Adrenaline
• Increases heart
rate, constricts
blood vessels,
dilates air
passages and
participates in the
fight or flight
• Noradrenaline
• Affects parts of the
brain (amygdala)
where attention and
responses are
• Directly increases
heart rate, triggering
the release of glucose
from energy stores,
and increasing blood
flow to skeletal
muscle (F or F)
Cortex Hormone
• Cortisol – glucocorticoid, keeps
blood glucose levels stable
• It stimulates the release of amino acids from
the body
• It stimulates lipolysis, the breakdown of fat
• It stimulates the production of glucose from
newly-released amino acids and lipids
• It increases blood glucose levels in response
to stress, by inhibiting glucose uptake into
muscle and fat cells
• It strengthens cardiac muscle contractions
• It increases water retention
• It has anti-inflammatory and anti-allergic
Adrenal Gland Disorders
Cushing’s Syndrome
• Hypersecretion of
cortisol (for long
periods of time)
• Round “moon” face
and “buffalo hump”
*Overuse of steroid
medication and
pituitary tumors can
cause this treatable
Addison’s Disease
• Hyposecretion of cortisol
• Low blood pressure results
• Increased pigmentation, weight loss, muscle
weakness, salt craving, nausea, irritability, sexual
• When the body is under stress (e.g. fighting an
infection), this deficiency of cortisol can result in a
life threatening “Addisonian” crisis characterized
by low blood pressure.
• The pancreas is a
large gland behind
your stomach that
helps the body to
maintain healthy
blood sugar (glucose)
• Contains islands of
cells called the Islets
of Langerhans which
secrete glucagon and
Pancreas Hormones
• Glucagon – stimulates the liver to
break down glycogen, raises blood
sugar concentration
• Insulin – decreases blood sugar
concentrations, affects the uptake of
glucose by cells
*Both hormones work together
to maintain a balance in the
blood sugar
• Diabetes Mellitus – results from an
insulin deficiency, blood sugar rises
(hyperglycemia) and excess is
excreted in the urine.
• Type I - insulin dependent diabetes
mellitus or juvenile onset diabetes,
often caused by inherited immune
disorder that destroys pancreatic
Adult Onset Diabetes
• Type II – mature onset diabetes
(usually after the age of 40), often
individuals are overweight, can be
controlled with diet and exercise
Limb Amputation
• Having high blood sugar levels for a long
time can damage nerves throughout the
• When nerves are damaged, they can't
send messages, the messages they send
get interrupted, or the messages get
mixed up. This is a condition called
diabetic neuropathy.
• High blood sugar affects:
• Long nerves from the spinal cord that allow us to
move and feel.
• Smaller nerves that support our body organs
including the heart, stomach, and bladder.
Insulin Effects
• Injection of insulin will lower the
blood sugar levels
• Hypoglycemia can occur if levels
become too low, can be cured with
direct injection of glucose or with
eating something high in sugar. This
is why diabetics often have glucose
tablets or candy.
Other Endocrine Organs
• Pineal Gland – located between the
cerebral hemispheres, secretes
melatonin, important for maintaining
Circadian rhythms (light and dark
Reproductive Organs
• Kick in during puberty with stimulation
from the brain
• Testes- secrete testosterone
– Develops male sex organs, body hair,
bone and muscle mass, and “well
• Ovaries- secrete progesterone/estrogen
– Estrogen: development and regulation
of female reproductive system and
– Progesterone: prepares and maintains
uterine lining for pregnancy, vital to stay
Estrogen vs.
• Pre-Synthesized from cholesterol
• Testosterone is converted into
estrogen in the ovaries using an
• All men have small levels of
estrogen, but capable of producing
• Anabolic steroids
are artificially
produced hormones
that are the same as,
or similar to,
androgens, the maletype sex hormones in
the body.
• There are more than
100 variations of
anabolic steroids. The
most powerful
androgen is
Doping for Gold
• “Starting at age 15, I got the blue pill but also a
bunch of other substances,” explains the team
pursuit specialist, who is now forced to live on
disability benefits. “And before competitions, we
got injections every day. Within two-three hours,
you could feel your body getting warmer. But the
coaches didn’t tell us what it was that we were
getting. They called it ‘supporting substances.’”
Sports Doping
• Lance Armstrong admits to doping
– 7 time Tour de France winner
– “ Cyclist Lance Armstrong has been
stripped of his record seven Tour de
France titles and banned for life by the
United States Anti-Doping Agency
– The USADA has accused Armstrong of
being involved in "the most
sophisticated, professionalized and
successful doping program that sport
has ever seen". AP
Can Doping Be
• Undercover Investigation
• HGH and Sports Recovery