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Ex Phys Endocrine 1
Ex Phys Endocrine 1
160
Physiology
Graduate
09/22/2014

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Term
What makes an endocrine gland an endocrine gland?
Definition
endocrine glands are ductless glands that secrete hormones
Term
what are hormones
Definition
chemical messengers that can regulate biological processes
Term
what types of biological processes can hormones regulate?
Definition
metabolism, water balance, reproduction, growth and development
Term
where are hormones metabolized?
Definition
hormones can be metabolized in any tissue that has a receptor for the hormone
Term
what is a target tissue?
Definition
a tissue that has a receptor for the hormone
Term
what is hormone degradation?
Definition
hormone degradation occurs when the liver removes hormones from the blood and deactivates them
Term
what is metabolic clearance of a hormone
Definition
pulling the hormone out of the blood, either for uptake or for degradation
Term
what 2 factors collectively define metabolic clearance rate
Definition
hormone uptake at the target tissue + hormone degradation in the liver
Term
is metabolic clearance rate the same for all hormones
Definition
no
Term
what is a down receptor?
Definition
a receptor that can't respond to the hormone for 1 of 2 reasons
Term
what are the 2 causes of a down receptor
Definition
the receptor could be saturated (in use by hormones) OR it could be inside the cell nucleus and not available for hormones to bind
Term
do hormones each have an individual purpose?
Definition
no. individual hormones can have a number of different jobs
Term
what determines a hormone's role?
Definition
environmental factors
Term
what is an acute exercise session?
Definition
a single exercise session
Term
what is chronic exercise?
Definition
training
Term
How does training change hormone levels at baseline?
Definition
If a person becomes trained, most hormones at rest will tend to be a little bit lower than before training.
Term
How does training change hormone levels at submaximal exercise
Definition
all submaximal exercise responses of hormones are lower in a trained person than in untrained people
Term
How does training change the hormone response to maximal exercise?
Definition
A maximal exercise response of hormones can be greater in a trained person because the person can handle the increase in hormones.
Term
what is an exception to the "lower baseline hormone levels in a trained person" rule?
Definition
if you do lots of resistance training, you might find that your resting testosterone levels are slightly higher. This is different from what we usually see with hormones
Term
how do hormones change to an acute bout of exercise?
Definition
hormones can increase, decrease, or remain the same with an acute bout of exercise.
Term
what determines the amount that a hormone responds to an acute bout of exercise?
Definition
the exercise dose
Term
what is exercise dose?
Definition
intensity, frequency, duration of exercise
Term
why do hormones respond to exercise?
Definition
hormones have a physiological role to help the body meet demands of exercise
Term
what are the necessary actions of hormones that help the body meet the demands of exercise?
Definition
Hormones: 1. Increase energy expenditure by mobilizing substrates and turning on energy pathways, 2. Increase cardiovascular adjustments, 3. Alter hydration status for thermoregulation, 4. Increase stress reactivity and the immune system
Term
How is the response of hormones with exercise a feed forward mechanism?
Definition
The changes made by hormones can further increase hormonal responses
Term
Give an example of a feed forward response of a hormone
Definition
increasing energy production can increase heat which can cause fluid loss which can cause further endocrine response
Term
In what ways is hormone concentration in the blood increased?
Definition
increased hormone production, increased hormone secretion, decreased metabolic clearance of hormone, increased hemoconcentration
Term
in what ways is hormone concentration in the blood decreased?
Definition
Decreased hormone production, decreased hormone secretion, increased metabolic clearance of hormone, increased hemodilution
Term
define concentration
Definition
the amount of solid in a liquid
Term
what is hemoconcentration?
Definition
loss of blood fluid (loss of plasma volume)
Term
how does hormone concentration change with hemoconcentration?
Definition
blood fluid is lost, so the amount of hormone per unit of blood is increased
Term
what is hemodilution?
Definition
increased plasma volume
Term
how does hormone concentration change with hemodilution?
Definition
if we have increased plasma volume, the concentration of hormone will decrease
Term
with what does fluid shift in and out of the blood?
Definition
exercise, probably other stuff too
Term
what has to happen for there to be a steady state of hormone level with exercise?
Definition
Either the amount of metabolic clearance = the amount of secretion OR hemoconcentration = hemodilution
Term
with a steady state of hormone during exercise, is the hormone truly not changing?
Definition
It might look like exercise has no effect on the hormone, but there are actually factors to increase and decrease the hormone that occur in the same amount
Term
what are modifiers of hormonal response to exercise?
Definition
gender, age, nutritional status, hydration status, affective state, hypobaric conditions, hyperbaric conditions
Term
What will my hormonal response be if I start an exercise bout and am low in carbohydrates, dehydrated, and feeling blue?
Definition
My hormonal response would be much greater than if those things were in a proper status prior to starting the exercise
Term
what factors and conditions influence hormonal response to exercise?
Definition
competitive vs training stress; time of day; time of year; mode of exercise; recovery response; bioavailability of the hormone
Term
what is the recovery response?
Definition
some hormones respond rapidly after an exercise session, quickly returning to normal; some hormones take a long time to increase after exercise and then slowly return to normal; some hormones decrease after an exercise session
Term
what affects the bioavailability of the hormone?
Definition
hormone half-life
Term
what is the hormone half-life of ACTH
Definition
20 minutes
Term
what is the half-life of antidiuretic hormone?
Definition
20 minutes
Term
what is the half life of aldosterone
Definition
20 minutes
Term
what is the half life of the catecholamines
Definition
2-2.5 minutes
Term
what is the half life of cortisol?
Definition
60 minutes
Term
what is the half life of glucagon?
Definition
5 minutes
Term
what is the half life of growth hormone?
Definition
20 minutes
Term
what is the half life of insulin?
Definition
10 minutes
Term
what is the half life of testosterone?
Definition
70 minutes
Term
what is the half life of TSH?
Definition
50 minutes
Term
what is the half life of triiodothyronine?
Definition
24 hours
Term
what does "bioavailability" include?
Definition
amount of free hormone, number of functional receptors, affinity level of receptors for the hormone, post-receptor amplification mechanisms
Term
what is a free hormone
Definition
a hormone not currently bound to a receptor site
Term
how does chronic exercise affect basal resting hormone levels (for the most part)?
Definition
chronic exercise reduces basal resting hormone levels
Term
how does chronic exercise affect hormone response to maximal exercise?
Definition
maximal exercise in a trained person will provoke larger hormone responses than before the training
Term
why does submaximal exercise not provoke an increased hormone in a trained person?
Definition
exercise becomes less of a physical stress to the body in a trained person
Term
In what ways is exercise less of a physical stress to a trained person?
Definition
Training improves homeostasis so that exercise no longer messes things up on the inside of cells; target tissue doesn't need as much hormone to get the desired effect because it has improved sensitivity
Term
How quickly after exercise does insulin begin to return to its pre-training response values?
Definition
72 hours
Term
what happens to hormones with continued inactivity after training?
Definition
they return to their pre-training values
Term
what are the 2 catecholamine hormones
Definition
norepinephrine, epinephrine
Term
what are the specific ways in which norepinephrine and epinephrine affect metabolism?
Definition
1. increase breakdown of glycogen into glucose in liver and muscle; 2. increase breakdown of triglycerides into free fatty acids and glycerol; 3. decrease entry of glucose into some cells and tissues because of a preferential treatment of the oxidation of free fatty acids
Term
During an incremental, progressive exercise test resulting in maximal effort, how will plasma norepinephrine and epinephrine change?
Definition
as oxygen consumption increases, plasma norepinephrine and epinephrine increase exponentially with the increase in norepinephrine beginning before the increase in epinephrine
Term
is there typically more norepinephrine or epinephrine in circulation?
Definition
more NE
Term
During a submaximal, steady state exercise at a fixed intensity, what is the catecholamine response?
Definition
The catecholamine response increases dramatically at first and then increases slowly throughout the duration of exercise.
Term
At a higher magnitude of steady state exercise, how will the catecholamine response change compared to a lower magnitude of steady state exercise?
Definition
at a higher magnitude of steady state exercise, the magnitude of increase of catecholamines will be higher
Term
what determines whether a tissue will respond to catecholamines?
Definition
The tissue must have a receptor for the catecholamine
Term
what determines the magnitude of the effect of catecholamines on a tissue
Definition
the number of receptors, the level of receptor saturation
Term
what are the 2 receptors to which norepinephrine binds?
Definition
alpha 1, beta 1
Term
what are the receptors to which epinephrine binds at LOW doses?
Definition
beta 2, slightly beta 1
Term
what are the receptors to which epinephrine binds at HIGH doses?
Definition
primarily alpha 1
Term
what catecholamine responds to alpha 1?
Definition
norepinephrine. Epinephrine at high doses.
Term
Why does it take high doses of alpha 1 receptors to take E?
Definition
alpha 1 receptors have a greater affinity for NE. They will switch to having an affinity for E when there is a lot of E.
Term
What are the effects of a catecholamine binding to an alpha 1 receptor?
Definition
vasoconstriction in the GI and vascular systems
Term
Why does vasoconstriction from alpha 1 receptors occur more strongly in the GI system than in the vascular system?
Definition
there are more alpha 1 receptors in the GI system than in the vascular system
Term
what catecholamine responds to beta 1 receptors?
Definition
N, slightly E
Term
what does it meant hat N and slightly E binds to Beta 1 receptors?
Definition
beta 1 receptors like to respond to norepinephrine, but they will take epinephrine if there is no other option
Term
what do beta 1 receptors do?
Definition
cause myocardial acceleration and myocardial contractility (heart beats more powerfully)
Term
what hormone binds to beta 2 receptors?
Definition
E at low dosage
Term
why do beta 2 receptors only receive E at low dosage?
Definition
beta 2 receptors become overwhelmed with too much epinephrine
Term
what is the result of catecholamines responding to beta 2 receptors?
Definition
vasodilation in arterioles (heart, muscle)
Term
what is the effect of training on basal levels of catecholamines?
Definition
slightly lower. Possibly no change since you don't typically have a lot of catecholamines floating around at rest
Term
what is the submaximal exercise response of catecholamines in a trained person compared to an untrained person?
Definition
slightly lower catecholamines in the trained person. Right after submaximal exercise, a trained individual will have decreased catecholamines.
Term
what is the maximal exercise response of catecholamines in a trained person compared to an untrained person?
Definition
could be increased since you have the ability to enhance production and secretion. The levels of catecholamines in the trained person are less up until the point where you reach maximal exercise
Term
why does an untrained person have an increase in catecholamines with exercise?
Definition
stress reactivity causes over response of sympathetic nervous system
Term
what is the primary hormone responsible for the uptake and storage of glucose and free fatty acids?
Definition
insulin
Term
what creates changes in insulin?
Definition
glucose
Term
what happens with insulin if blood glucose increases?
Definition
insulin increases
Term
how does the concentration of insulin change during exercise?
Definition
the concentration of insulin decreases during exercise as intensity increases
Term
compare the effects of insulin and glucagon in one word
Definition
opposite
Term
what stimulates insulin?
Definition
increased glucose in the blood
Term
what does insulin do?
Definition
causes glucose to move out of the blood and into the tissue of muscle, adipose, and liver
Term
what stimulates glucagon?
Definition
decreased glucose in the blood
Term
what does glucagon do?
Definition
glucagon breaks down adipose into triglycerides to elevate blood FFA and glycerol AND causes amino acids and glycogen to break down into blood glucose
Term
what are the 2 transport proteins on skeletal muscle cells?
Definition
Glut 1, Glut 4
Term
what do glut 1 transporters do?
Definition
constantly pull glucose into the skeletal muscle
Term
do glut 1 transport proteins require insulin to work?
Definition
no
Term
are there many glut 1 transporters in skeletal muscle?
Definition
no, just a few
Term
what does muscle tissue need to be able to exercise?
Definition
glucose
Term
how is insulin helpful to skeletal muscle?
Definition
helps it to pick up glucose from the blood
Term
where are glut 4 transport proteins found?
Definition
muscle
Term
are glut 4 or glut 1 transport proteins more common?
Definition
glut 4 transport proteins are more common
Term
what is usually necessary for glut 4 transport proteins to work?
Definition
insulin and glucose
Term
does glut 4 ALWAYS require insulin to tell it what to do?
Definition
no
Term
when does glut 4 not need insulin to tell it to pull glucose in?
Definition
during exercise
Term
what makes fat cells pull glucose in out of the blood?
Definition
insulin
Term
are adipose cells insulin dependent or independent
Definition
insulin dependent
Term
how does the battle over glucose between adipocytes and muscle cells change during exercise and why?
Definition
When Glut 4 transport proteins become insulin independent, the muscle cells are more able to pick up more glucose without insulin. The adipocytes continue to require insulin, but there is less insulin during exercise so the adipocytes are not pulling as much glucose out of the blood. There is more glucose in the blood available for muscle, and the muscle is better at getting the glucose out of the blood.
Term
what 2 things increase the number of glut 4 transporters in the membrane
Definition
insulin and exercise
Term
what 2 things activate glut 4 transporters at rest
Definition
insulin and exercise
Term
how are glut 4 transport proteins able to become insulin independent during exercise?
Definition
intracellular signaling mechanisms help to up regulate glut 4 transport proteins
Term
what are the changes in insulin in response to a submaximal exercise session (steady state)?
Definition
insulin decreases initially and then plateaus
Term
how do trained and untrained people compare in insulin response to steady state, submaximal exercise bout?
Definition
trained and untrained both have reduced insulin, but an untrained person has a slightly greater loss of insulin
Term
how does training change your basal insulin levels?
Definition
if you have low insulin levels at rest already, training won't make a big difference. But if you have high insulin levels (prediabetic), your basal insulin levels will decrease with training.
Term
why does insulin decrease during exercise?
Definition
we stop producing insulin during exercise because our glut 4 transporters are working now AND catecholamines decrease production of insulin. We will use up the insulin that is there, but no more will be produced to replace it.
Term
why does a trained person have less of a decrease in insulin?
Definition
training creates a smaller catecholamine response. Catecholamines stop insulin production. With fewer catecholamines, there will be less of a decrease in insulin.
Term
what are the differences in insulin levels in a trained vs untrained person during a maximal exercise bout?
Definition
a maximal exercise bout will create a GREATER decrease in insulin in a trained person than in an untrained person.
Term
why does a maximal exercise bout create a greater decrease in insulin in a trained person than in an untrained person.
Definition
The trained person at maximal exercise can push harder than an untrained person, resulting in a greater catecholamine response and therefore a greater insulin suppression.
Term
What is Type II diabetes?
Definition
tissues not responding to insulin = receptors are either not there or not functional.
Term
how to decrease insulin in type 2 diabetes?
Definition
diet, exercise, medications
Term
what is insulin sensitivity?
Definition
the ability to move glucose into tissues with less insulin
Term
how can you improve insulin sensitivity
Definition
training: after 14 weeks of physical training, the tissue is much more sensitive to insulin, meaning it takes very little insulin to move glucose in.
Term
what is insulin resistance?
Definition
a condition in which cells fail to respond to the normal actions of hormones.
Term
do we want high or low insulin sensitivity?
Definition
we want high insulin sensitivity
Term
do we want high or low insulin resistance
Definition
we want low insulin resistance
Term
how does the amount of glucagon change during exercise as you move from low to moderate to high intensity?
Definition
glucagon increases with exercise as you increase in intensity
Term
how does glucagon change over the course of a submaximal, steady state exercise?
Definition
glucagon will increase and will eventually plateau
Term
does a trained or untrained person need less glucagon during exercise?
Definition
a trained person needs less glucagon during exercise
Term
why does a trained person need less glucagon during exercise than an untrained person?
Definition
The amount of fats you're metabolizing as an energy source influences the amount of glucagon you need to break down glycogen in the liver to make glucose. A trained person is better at breaking down fats into an energy result. As a result, a trained person needs less glucagon during exercise to tell the liver to break down glycogen into glucose.
Term
what is the change in basal levels of glucagon with exercise training?
Definition
no change at the basal level
Term
why is there no change at the basal level of glucagon at rest?
Definition
there isn't normally a lot of glucagon in the blood at rest
Term
what is the change in glucagon in a trained person with submaximal exercise?
Definition
decrease in glucagon
Term
what is the maximal exercise response of glucagon in a trained person?
Definition
increase
Term
how does a single exercise bout affect the sympathetic nervous system?
Definition
exercise activates the sympathetic nervous system
Term
how does the sympathetic nervous system affect catecholamines?
Definition
the SNS increases catecholamines
Term
how does E, NE affect the liver?
Definition
E, NE cause the pancreas to decrease insulin and increase glucagon production
Term
why is it helpful that E, NE decrease insulin during exercise?
Definition
when you decrease insulin, there will be greater breakdown of triglycerides into FFA.
Term
why is it helpful that glucagon is increased during exercise?
Definition
increased glucagon (and increased catecholamines) promote breakdown of glycogen into glucose. This increases blood glucose and FFA for energy.
Term
what are the 4 controls of the breakdown of muscle glycogen for utilization
Definition
1. E and NE to activate cyclic AMP; 2. Calcium to implement glycogen phosphorylase; 3. glucagon; 4. glycogenolysis
Term
at what exercise intensity does the greatest depletion of glycogen occur
Definition
75% VO2 max
Term
why do you have less glycogen depletion at exercise intensity levels lower than 75% VO2 max?
Definition
at lower intensities you have greater fact contribution
Term
why do you have less glycogen depletion at exercise intensities greater than 75%?
Definition
you can't maintain higher intensities for a long enough period of time.
Term
do you have higher or lower plasma epinephrine concentration at high levels of exercise intensity?
Definition
more epinephrine with higher intensity exercise
Term
What are the mechanisms to maintain blood glucose during exercise?
Definition
1. mobilization of glucose from glycogen in the liver; 2. mobilization of FFA from adipose tissue to spare blood glucose; 3. gluconeogenesis from amino acids, lactic acid, and glycerol; 4. hormonal blocking to prevent glucose from leaving the blood and to force some tissues to use FFA during exercise to spare blood glucose
Term
at what point does gluconeogenesis from amino acids, lactic acid, and glycerol occur MOST?
Definition
during recovery from exercise
Term
what organ produces insulin and glucagon
Definition
pancreas
Term
why is there so much NE in our blood?
Definition
sympathetic spillover. There are many nerve fibers that release lots of NE.
Term
what are the 2 glands where epinephrine is made
Definition
2 adrenal medullary glands
Term
what are the primary destinations for NE?
Definition
liver, pancreas, skeletal muscle
Term
what happens to all the extra NE that the liver, pancreas, and skeletal muscle can't use?
Definition
the NE will diffuse into nearby capillary beds as spillover
Term
NE is an indicator of what?
Definition
sympathetic nervous system
Term
E is an indicator of what?
Definition
adrenal medulla
Term
when does E bind to alpha 1 receptors
Definition
extremely intense exercise
Term
what do alpha 1 receptors cause?
Definition
vasoconstriction
Term
what happens at extremely high exercise when alpha 1 receptors are activated by E?
Definition
vasoconstriction: decreased blood => decreased oxygen to muscle => decreased waste removal => feels bad => most people won't push that hard
Term
why are there no alpha 1 receptors in the heart and brain?
Definition
we don't want to be able to shut down blood flow to the heart and brain
Term
why do E and NE have overlapping and redundant actions?
Definition
NE and E create processes that have to occur or we will die. So we ant to have a back-up to be certain that the processes will occur to keep us alive
Term
what hormone overlaps with insulin?
Definition
insulin like growth factors
Term
why is it bad for a person with a glucose of 300 to exercise?
Definition
With this much glucose in the blood, the muscle cell will take in all the glucose from the blood rapidly. Glycolysis likes to do glucose metabolism. If glucose is showing up in the cell during exercise, the cell will ignore the glycogen stores in the muscle. The transporters will turn on and run fast because there is a high concentration of glucose in the blood. The rapid pulling in of glucose from the blood can lead to rapid hypoglycemia
Term
What is the ADA recommendation for exercise for people with uncontrolled diabetes?
Definition
low intensity and intermittent: walk for 5 minutes, rest for 5 minutes. Make certain that the person feels good and is not rapidly exhausting glucose in their blood.
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