BIOL 2030 Human Anatomy & Physiology II
What body system(s) malfunctioned to cause
these differences?
Skeletal,
Muscular and
other systems
involved but
caused by
problems with
the __________
system!
What is the main function of
the endocrine system?
Regulate tissues/cells
•*
•*
•*
•*
•*
Any other system(s) that
regulate other tissues?
Nervous System
How did the nervous
system regulate other
tissues?
What was the medium for
transmitting the control
signal?
Intercellular communication
via the ______________ can
be likened to using the
telephone and an FM signal…
The message goes …
Pulses (___________)
regulate response.
The Endocrine system on the
other hand is more like a radio
broadcast and AM signals…
The message is sent …
Concentration (________)
regulates response.
Historically these two systems thought to be very
independent. Now their interdependence is recognized
Which is frequency
modulated?
Which is amplitude
modulated?
One aspect shared between 2 systems is use
of intercellular chemical signals
Type
Function
Example
*
similar, adjacent tissue
Prostaglandins
*
different, nearby tissue
histamine
*
regulate other distant tissue
Thyroxine
*
produced by neuron
Oxytocin
*
secreted by neuron
Acetylcholine
*
secreted into environment
sex pheromone
Where do
hormones
come from?
The Endocrine
system is
comprised of
what organs
(glands)?
Actually other organs are also capable of secreting
hormones… Example the heart and the placenta
What are the characteristics of hormones?
3 general characteristics…
1) ___________…
2) ___________…
3) ___________…
Do hormones persist once formed?
_______________! They are “decommissioned”
at various rates depending on the nature of the
hormone (some hormones are removed from circulation
within 2 min. of secretion).
Hormones are only active if “______” and are
usually only acted upon if “______”
Amount of time to remove 1/2 the initial dose is
the ______________.
________ based hormones have short 1/2 lives
________ based (steroids) have long 1/2 lives
How are hormones distributed?
All hormones by definition travel
via _________!
They can travel either:
1) _______, in an unbound state
2) _______ with plasma proteins
When hormones are bound
to their protein (usually
specific protein for each
hormone) they exist in an
___________ of bound and
free hormones.
Response?
Take 5!!!
How is the half-life of a
hormone affected by a
decrease in the
concentration of the specific
plasma protein to which
that hormone binds?
Discuss with your neighbor
and predict an answer
What are the chemical categories of hormones?
Hormones fall into 2 basic categories:
1) _________________
Biogenic amines (amino acid derivatives) ~ T4
Polypeptides ~ TRH
Would you expect
Glycoproteins ~ TSH
Proteins ~ GH
these to be
hydrophylic or
hydrophobic?
2) ______________
Steroids (made of cholesterol) ~ Testosterone
How are hormones distributed?
What are the patterns of hormone secretion?
3 characteristics…
1) _________… stable levels.
2) _________… levels change dramatically.
3) _________… levels change, but at regular intervals.
Which is which?
How do hormones work?
Hormones bind
to _________
receptors on
___________.
This binding
results in
________ of
_____________.
How is hormone secretion stimulated?
3 patterns of regulation…
1)
The level of a monitored
substance initiates response
and secretion of hormones.
Ex. elevated blood glucose
results in increased insulin
levels, which in turn
reduce blood glucose
levels.
How is hormone secretion stimulated?
3 patterns of regulation…
1) Other substance acting
on gland (humoral)
2)
Nervous stimulation results
in the release or inhibition
of hormones.
Ex. epinephrine released as
a result of sympathetic
stimulation.
How is hormone secretion stimulated?
3 patterns of regulation…
1) Other substance
acting on gland
(humoral)
2) Neural control glands
Nervous stimulation results
in the release or inhibition
of hormones.
How is hormone secretion stimulated?
3 patterns of regulation…
1) Other substance acting
on gland (humoral)
2) Neural control glands
3)
The secretion of one
hormone influences the
secretion (+ or -) of another hormone.
Ex. TRH causes release of TSH
How is hormone secretion inhibited?
3 patterns of regulation…
1) Other substance acting
on gland (humoral)
2) Neural control glands
3) Hormonal control of
other endocrine glands
The secretion of one
hormone influences the
secretion (+ or -) of another hormone.
How is hormone secretion controlled?
The activity of endocrine glands
depends on Feedback mechanisms
(see pgs. 9-12).
These regulate one or more variables
and often consist of 3 components:
1) ___________What are their function?
2) ____________________What function?
3) ___________ How about their function?
2 main situations…
1) Variable is maintained within “+” & “-”
limits
Set point
Normal range
thresholds
• Where are the receptors working?
• Where does the receiver respond?
• Where is the effector(s) active?
2 main situations…
2) The variable moves away from a
“normal” value
Set point
Normal range
thresholds
• Where are the receptors working?
• Where does the receiver respond?
• Where is the effector(s) active?
Comparing the status of the variable prior to and after
the response... which one would you classify as positive
feedback and which one is negative feedback???
Set point
Set point
An example from your body…
Case Study pg. 580
Josie owns a business and works hard to manage her employees and make time for her family.
Over several months, she frequently felt weak, was often unable to concentrate, and felt cold
when others did not. In addition, she began to gain weight, even though she had a small appetite.
Finally, after noticing a large lump in her neck inferior and lateral to her larynx, Josie decided to
see her physician. A blood sample was taken, and the results indicated low levels of thyroid
hormones (hypothyroidism; see chapter 18), high levels of TSH, and low levels of iodine.
The doctor concluded that Josie had developed a goiter, or an enlarged thyroid gland. He
explained that the goiter had probably formed because her dietary intake of iodine was too low
over a prolonged time. Without iodine, Josie's thyroid gland was unable to synthesize thyroid
hormones. Thus, in response to low thyroid hormone levels, the anterior pituitary gland
continued to secrete the tropic hormone TSH, which caused the thyroid gland to keep getting
bigger and bigger. In addition, the hypothalamus continued to stimulate the anterior pituitary in
the absence of thyroid hormones.
Josie was treated with radioactive iodine (131I) atoms, which were actively transported into her
thyroid cells, where the radiation helped shrink her thyroid gland back to normal size.
Subsequently, Josie had to take dietary iodine supplements and thyroid hormone supplements
until her thyroid gland was able to produce thyroid hormones on its own again.
Case Study pg. 580
http://www.ijem.in/articles/2013/17/2/images/IndianJEndocrMetab_2013_17_2_228_109671_f2.jpg
Hormone
Membrane-Bound
Receptor
Intracellular
Receptor
Receptor/ion Receptor/G
channels
proteins
Opens/closes
channels
Receptor/intracellular
enzymes
Activates existing
enzymes
Cell Response
Activates
genes
Synthesizes new
enzymes
Why do tissue responses vary over time?
Target tissues can modify
their response to a
hormone by
Down- and Upregulation.
_____________
is the decrease in the number of hormone receptors.
Caused by:
1) Decrease in receptor _____________
2) Hormone/receptor binding can lead …
Is this pattern effective for Long-term constant
levels or short-term changing concentrations?
Why do tissue responses vary over time?
____________
is an increase
in hormone
receptors
For example, Follicle-stimulating Hormone
(FSH) causes and increase in the number of
Luteinizing Hormone (LH) receptors
Is this pattern effective for Long-term constant
levels or short-term changing concentrations?
Take 5!!!
Estrogen is a hormone secreted by the ovary.
It is secreted in > amounts after menstruation
and a few days before ovulation. Among its
many effects is causing up-regulation of
receptors for another hormone secreted by
the ovaries, progesterone. Progesterone is
secreted after ovulation and a major effect is
to cause the uterus to become ready for the
embryo to attach. Predict the result if the
ovary secretes too little estrogen?
Discuss with your neighbor and predict an answer
How are hormones removed from circulation?
4 mechanisms used:
1) ______________ -- enzymatically broken down by liver,
kidneys, lungs etc.
2) ______________ -- hormones that can’t be broken by
themselves are combined with another compound and then
they can be excreted.
3) _____________ -- some hormones can be excreted by
the kidneys in urine and by the liver in bile.
4) _________________________-- some hormones are
pumped back into cells that can re-use them later.
How do hormones and their receptors vary?
Receptors also fall into 2
major categories:
1)
Receptors embedded in the
plasma membrane with a
receptor site on the outside
and an “affector” component
inside.
2)
Receptors are in the cytoplasm
or in the nucleus of the cell.
How do hormones and their receptors vary?
Intracellular receptors
These receptors are in the cytoplasm or
nucleus of the host/target cell. Hormones
that bind to these receptors must be able to…
These hormones influence the manufacture
rate of cellular products or activate enzymes
How do hormones and their receptors vary?
Ex. Aldosterone
1)
2) ___________ with
receptor in cytoplasm
3) Hormone/receptor
complex …
4) Complex activates…
5) mRNA is …
6) ____________produce response
How do hormones and their receptors vary?
Membrane-bound
receptors
regulate/influence
cells via 2 basic
mechanisms:
1)
2)
How do hormones and their receptors vary?
What type of scenario is this?!?
How do hormones and their receptors vary?
1) Receptors that
activate
G Proteins
How do hormones and their receptors vary?
1) Receptors that activate G Proteins
How do hormones and their receptors vary?
1) Receptors that activate G Proteins
How do hormones and their receptors vary?
2) Hormones that influence intracellular enzymes
Some receptors
have internal
portions that
function as
enzymes, or they
are closely
associated with
enzymes.
Ex. Atrial natriuretic hormone and receptor cause
enzyme portion (GCase) to make cyclic GMP
How can < conc. of hormone result in > effects?
A _____ number of
hormones bind with
receptors activating
several existing
components, all of
which activate more
components
individually,
causing a large
number of final
product.
Is this more likely with
This is the
proteinaceous or lipid-based
_______________.
hormones?
Take 5!!!
Which hormone would have the
quickest effect… estradiol (sex
hormone) or insulin ? Why?
Discuss with your neighbor
and predict an answer