Download Endocrine System

Fight
or
Flight?
What changes
occur in your body
when you get
scared?
Endocrine System
a group of glands in
the body which secrete
hormones directly into
the blood.
Don’t look here
Don’t look here
either
Why does FSH (Follicle
Stimulating Hormone
affect the ovaries but
no other organs such
as the stomach?
Hormone
Hormones
molecules secreted into the
blood by the endocrine
glands.
They evoke specific responses
in target cells of the body.
Comparing the Nervous
and Endocrine Systems
Similarities
respond to stimuli
• maintain homeostasis
• secrete chemical messengers
that attach to receptors
• same target organs
Comparing the Nervous
and Endocrine Systems
Differences
Nervous response is faster
ex. Blink of an eye
Endocrine response lasts longer
ex. Changes during puberty
The Pancreas
The Pancreas
Endocrine Gland
Exocrine Gland
secretes hormones
secretes enzymes
into intercellular fluid
into a duct (tube)
into blood
leading to small
intestine
target organ(s)
Islets of
Langerhans
The pancreas produces
the hormones insulin
and glucagon
Why is insulin important?
diabetes
http://www.youtube.com/watch?v=nBJN7DH
83HA&NR=1
http://www.youtube.com/watch?v=V1LjRi8N
vv4
Insulin
Regulates blood glucose (sugar) in the
normal range
Stimulates cells of the body to absorb and
use glucose thereby decreasing blood sugar
levels
Secreted in response to: High blood glucose
Secretion inhibited by: Low blood glucose
Glucagon
Assists insulin in regulating blood glucose
(sugar) in the normal range
Actions are opposite of insulin
Stimulates many cells of the body to
release (or produce) glucose (increasing
blood sugar)
Secreted in response to:
Secretion inhibited by:
Low blood glucose
High blood glucose
How does a thermostat
work?
Sensor
detects high
blood sugar
level
Negative
Feedback:
Lowered blood
sugar leads to
shutting off of
insulin
production
Pancreas
secretes
insulin
Blood
sugar
level
drops
Sensor
detects low
blood sugar
level
Negative
Feedback:
Higher blood
sugar leads to
shutting off of
glucagon
production
Pancreas
secretes
glucagon
Blood
sugar
level rises
INSULIN
VS.
GLUCAGON
Disease due to insulin
deficiency: Diabetes
Disease due to excess
insulin: Hypoglycemia
1
Pituitary
Gland
2
Pancreas
Thyroid
4
Adrenal 5Glands
3
Testes
6
Ovaries
Goiter
Goiter
Thyroid
Gland
Goiter
•
•
•
noncancerous enlargement of
the thyroid gland
often associated with iodine
deficiency;
iodine is needed to make
thyroid hormone
Thyroid Hormones
The Pituitary is
the “master gland”
of the endocrine
system
Hormones from the Anterior Pituitary
• Thyroid stimulating hormone
• Adrenocorticotropic hormone (ACTH)
• Follicle stimulating hormone (FSH)
• Leutenizing Hormone (LH)
• Prolactin
• Growth Hormone
(cortisol)
So what causes Goiter?
Regulation of Thyroxin
Hypothalamus
No
TRHTRH
Pituitary Gland
TSH
No TSH
Thyroid Gland
thyroxin
Negative feedback
when the concentration of a
product reaches a certain level,
the product will inhibit it’s own
synthesis
Goiter
Thyroid Hormones
Deregulation of Thyroxin in
Goiter
Hypothalamus
No
TRHTRH
Pituitary Gland
TSH
No TSH
Thyroid Gland
NO iodine in diet
thyroxin
Thyroid releasing hormone
Thyroid stimulating hormone
cycle A recurring sequence of events;
e. g. the secretion of certain
hormones at regular intervals.
negative feedback loop
A biochemical pathway where the
products of the reaction inhibit
production of the enzyme that
controlled their formation.
Sensor
detects high
blood sugar
level
Negative
Feedback:
Lowered blood
sugar leads to
shutting off of
insulin
production
Pancreas
secretes
insulin
Blood
sugar
level
drops
Sensor
detects low
blood sugar
level
Negative
Feedback:
Higher blood
sugar leads to
shutting off of
glucagon
production
Pancreas
secretes
glucagon
Blood
sugar
level rises
Regulation of Thyroxin
Hypothalamus
No
TRHTRH
Pituitary Gland
TSH
No TSH
Thyroid Gland
thyroxin
Deregulation of Thyroxin in
Goiter
Hypothalamus
No
TRHTRH
Pituitary Gland
TSH
No TSH
Thyroid Gland
NO iodine in diet
thyroxin
Use the information in the following paragraph to create a map showing
the hierarchy of regulation involved in the secretion of cortisol

Since cortisol is so vital to health, the amount of cortisol
produced by the adrenals is precisely balanced. Like many
other hormones, cortisol is regulated by the brain’s
hypothalamus and the pituitary gland, a bean sized organ at
the base of the brain. First, the hypothalamus sends a
“releasing hormone” CRH (corticotropin releasing hormone)
to the pituitary gland . The pituitary responds by secreting
ACTH (adrenocorticotropin), a hormone that stimulates the
adrenal glands. When the adrenals receive the pituitary’s
signal in the form of ACTH, they respond by producing
cortisol. Completing the cycle, cortisol then signals the
pituitary to lower secretion of ACTH.
Similar to
Regulation of Cortisol
Hypothalamus
CRHCRH
No
Pituitary Gland
No
ACTH
ACTH
Adrenal Gland
cortisol
Grave’s Disease
Male athletes who
abuse anabolic
steroids often develop
sterility, testicular
atrophy, and enlarged
breasts.
EXPLAIN WHY.
Massive Hint:
Anabolic Steroids are
synthetic versions of
testosterone
Negative feedback
when the concentration of a
product reaches a certain level,
the product will inhibit it’s own
synthesis
so… when the body detects elevated levels
of “testosterone” (anabolic steroids), it stops
making it’s own testosterone and ...
converts
testosterone to
estrogen
(the female
hormone)!
How did the mouse on the left get so
huge?
Both of these mice have a defect
in a gene called obese (ob).
This mutation usually results in
a marked increase in the
amount of fat.
Administration of the
protein encoded by the
ob gene, called leptin,
reduced the body
weight of the ob mouse
on the right.
After four and a half weeks, the ob
mouse on the left, which did not
receive leptin, weighed approximately
67 grams while the mouse on the right
who received daily injections of leptin,
weighed 35 grams.
Normal mice weigh
approximately 24 grams,
a weight equivalent to
that of an orange.
How did the
injections of leptin
make the animal
lose weight?
Daily injections of leptin to ob
mice reduced body weight via
effects on food intake and
energy expenditure
(treated animals ate less and
also burned more calories)
Research suggests that fat cells
normally produce leptin to tell
the brain how fat the body is and,
therefore, whether an organism
should eat more or stop eating.
Obesity
 Obese
people may be lacking receptors
for leptin in their brains
–or May
have a mutated (defective) form of
leptin that fails to tell the brain that the
body has enough fat
Over 80% of adult-onset
diabetics are obese.
What is the link between
obesity and diabetes?
is it Resistin?
• discovery reported Jan. 2001
• hormone produced by fat tissue
• resistin levels reduced by antidiabetic drug rosiglitazone
• resistin levels increased in dietinduced and genetic forms of
obesity
Treatment of normal mice with
resistin
• impairs glucose tolerance
• impairs insulin action
• impairs uptake of glucose by
cells
Mice with diet-induced obesity
were treated with anti-resistin
antibody
results of treatment w/antibody
• lowered blood sugar levels
• improved action of insulin
Acromegally
Acromegally
Too much growth hormone in adulthood
Parathyroid Glands,
patches of tissue embedded
in the thyroid gland,
produce & secrete
parathormone.
 Parathormone controls
the metabolism of calcium
which is necessary for
nerve function, blood
clotting and proper growth
of teeth and bones.
1
Pituitary
Gland
2
Pancreas
Thyroid
4
Adrenal 5Glands
3
Testes
6
Ovaries
The Pineal Gland
The Pineal Gland
• produces melatonin
• production of melatonin by the pineal
gland is stimulated by darkness and
inhibited by light
• affects the modulation of sleep patterns
• both seasonal and circadian rhythms