Transcript Endocrine System 2

The Endocrine System
What is the system?
1. Made up of glands that produce
and secrete hormones (chemical
messengers)
2. Responsible for regulation of
growth, metabolism, sexual
development
3. Responses to stress and injury
4. Internal balance of
body systems (homeostasis)
OVERALL
• HORMONES are chemical
MESSENGERS that act on target cells (or
organs)
• Endocrine – secretions inside the body
• Exocrine – secretions outside the body
(sweat)
Major Structures
Hormone
Control
• Master Gland =
Pituitary Gland
• BUT…… the
hypothalamus
controls the
actions of the
pituitary gland!
Pituitary Gland
Control of Hormone
Release
Negative Feedback
• When hormone
levels rise, the
brain detects it
• Then, that gland is
shut off!!
Pituitary Gland
Hormones
•
•
•
•
•
•
•
•
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
Prolactin
• Stimulates milk production from a
woman's breasts after childbirth
Growth Hormone
• Stimulates growth in childhood and is
important for maintaining a healthy
body composition.
• 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
children
• 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
2001
• It is banned by the NCAA and IOC
Problems with pituitary can
result in dwarfism
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 Giant-wrestler/actor. He
suffered from acromegaly,
an over secretion of GH
Adrenocorticotropin
• 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
Hormone
• Stimulates the thyroid gland to make
thyroid hormones, which, in turn,
control (regulate) the body's
metabolism, energy, growth and
development, and nervous system
activity.
Luteinizing/Follicle Stimulating
Hormone
• LH regulates
testosterone in
men and estrogen
in women.
• FSH promotes
sperm production
in men and
stimulates the
ovaries to release
eggs (ovulate) in
women.
Oxytocin
• causes milk letdown in nursing
mothers and contractions during
childbirth.
Antidiuretic Hormone
• Also called vasopressin, is stored in
the back part of the pituitary gland
and regulates water balance.
• If this hormone is not secreted
properly, this can lead to problems of
sodium (salt) and water balance, and
could also affect the kidneys so that
they do not work as well.
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) & Tri-iodothyronine (T3) both increase the rate at which cells
release energy from carbohydrates
• Calcitonin – regulates the blood
concentration of calcium
• BMR – basal metabolic rate : how many
calories the body must consume to
maintain life
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
goiters.
GOITERS!
Hypothyroidism
• Early symptoms:
• Being more sensitive to
cold
• Constipation
• Depression
• Fatigue
• Heavier menstrual periods
• Joint or muscle pain
• Paleness or dry skin
• Thin, brittle hair
• Weakness
• Unintentional weight gain
• a condition in
which the thyroid
gland does not
make enough
thyroid hormone.
Hypothyroidism: Before
and After Treatment
Cretinism (hypothyroidism in
infants)
Hyperthyroidism/Graves
Disease
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
kidney.
• 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
response)
Medulla Hormones
Epinephrine
• Adrenaline
• Increases heart
rate, constricts
blood vessels,
dilates air
passages and
participates in the
fight or flight
response
Norepinephrine
• Noradrenaline
• Affects parts of the
brain (amygdala)
where attention and
responses are
controlled
• 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
effects
Adrenal Gland Disorders
Cushing’s Syndrome
• Hypersecretion of
cortisol
• Round “moon”
face and “buffalo
hump”
Addison’s disease
• Hyposecretion of cortisol
• Low blood pressure results
• Increased pigmentation, weight loss,
muscle weakness, salt craving,
nausea, irritability, sexual
dysfunction
Pancreas
• The pancreas is a
large gland behind
your stomach that
helps the body to
maintain healthy
blood sugar (glucose)
levels.
• Contains islands of
cells called the Islets
of Langerhans which
secrete glucagon and
insulin
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
• Diabetes Mellitus – results from an
insulin deficiency, blood sugar rises
(hypoglycemia) 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
cells
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
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 candy.
Other Endocrine Organs
• Pineal Gland – located between the
cerebral hemispheres, secretes
melatonin, important for maintaining
Circadian rhythms (light and dark
activity)
• Reproductive Glands – testes and
ovaries – testosterone,progesterone,
estrogen
Estrogen vs.
Testosterone
• Pre-Synthesized from cholesterol
• Testosterone is converted into
estrogen in the ovaries using an
enzyme
• All men have small levels of
estrogen, but capable of producing
more
Steroids
• 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
testosterone.