Recitation # 07
The goal of this recitation is to discuss basic
physiology of the GI system, the control of
metabolism, food intake and energy balance.!
The sections for this recitation are:!
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Question and answer for GI and metabolism lectures:
• 
Ranking of most important items for recitation # 07
–  What is that this recitation question is really asking, and how would you
answer it based on its “a,b,c,d” requested format ???.
–  For additional help with your answer, look at what a gastro-intestinal
“circle” and a thyroid “circle” component might look like while
interacting on Thanksgiving day. Why after gorging you sweat, do not
move (“couch potato”), and just watch, hyperventilating, a football game.
–  In order to answer this recitation question you need to understand all
material tested in your first and second exams plus the last two lectures.
A Model of Active Learning
• 
Probably a single most important tip for the course is to prepare SENTENCES with what you
consider are the main “punch lines” for each lecture. You should RANK them in what you
consider is a list from most to less important ideas given in each lecture. You should EDIT
them, as for example, checking if more than one sentence might be combined into a better
sentence. Finally, make sure that your sentences cover the whole of the topic presented in
each lecture. Use this list to discuss material with fellow students and with your instructor."
• 
Please be aware that in order to write a single, concise and informative sentence you need to
UNDERSTAND, rather than memorize, a piece of information. To test yourself on how good
you are doing, check if your sentence used your own words or if you are just borrowing part
of a sentence you read in your textbook. Consider that if you can not write an idea into a
single sentence, you probably have not yet understood the material.!
• 
When you are editing your notes, either from lectures or from your textbook, it is important to
have a “PLAN” that tells you where are you going with your editing. A good suggestion for
this plan is to develop a set of QUESTIONS that you think each lecture was attempting to
answer. List all possible questions, then edit and rank the questions, and finally answer them
by merging your lecture notes and the notes you might have summarized from your textbook.!
• 
The PARAGRAPHS in the following slides are an example of notes you might have taken
from a lecture or from a textbook. Use these notes as an exercise by turning them into
sentences, then editing them, and finally by ranking them. Make sure you merge your notes
from lectures with your notes from your textbook and make sure your ranked sentences
cover the whole material presented in lectures.!
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A Model of Active Learning
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What is the goal for the system
or lecture topic you are now
studying ?!
Which are its main structures
and its main functions ?!
Which are its main structure function relationships at the
different organizational levels ?!
Which are its main control
elements at the different
organizational levels ?!
Which are its main inputs,
integrators, outputs, and
feedback elements ?!
Which are its main links or
relationship with other systems
or lecture related topics ?!
Which are its main homeostatic
failures or clinical pathologies ?!
A Model of Active Learning
Lectrure #19
GI motility, secretion,
digestion and absorption
Lecture #22
Regulation of organic
metabolism, growth and
energy balance
Which are the questions ?
Which are the questions ?
Which are the answers ?
Which are the answers ?
Which are the statements ?
Which are the statements ?
You are welcome to drop by my office with your questions and
statements to discuss them and thus review to course material!
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A Model of Active Learning
Lectrure #23
Neuroendocrine control of
food intake and energy
balance
Remember that there are
three lectures related to GI
function.
Which are the questions ?
Which are the answers ?
Which are the statements ?
You are welcome to drop by my office with your questions and
statements to discuss them and thus review to course material!
Recitation question # 07
The seventh recitation question attempted to “force” you to think on two
metabolic control systems operating simultaneously on a common integrating
system, the hypothalamic paraventricular nucleus (PVN). Your answer should
follow the (a,b,c,d) sub-question structure you have used before (see next
slide)."
If you can not write an idea into a single sentence,"
you probably have not yet understood the material.
3
Recitation question # 07
The seventh recitation question attempted to “force” you to think on two
metabolic control systems operating simultaneously on a common integrating
system, the hypothalamic paraventricular nucleus (PVN) Your answer should
follow the (a,b,c,d) sub-question structure you have used before (see below)."
If you can not write an idea into a single sentence,"
you probably have not yet understood the material.
Recitation question # 07
structure
a)
b)
Which, increase
or decrease?
function
How do
you know?
c)
Parts to total?
d)
Two feedbacks and
an absolute
requirement?
4
Physiology of Metabolism, Food Intake
and Energy Balance
∑
S
E
Physiology of Metabolism, Food Intake
and Energy Balance
5
Physiology of Metabolism, Food Intake
and Energy Balance
Absortive
State
6
Physiology of Metabolism, Food Intake
and Energy Balance
Post - Absortive
State
Physiology of Metabolism, Food Intake
and Energy Balance
glycogen phosphorilase
glucose
G-6-Pase
glycogen
G-1-P
transaminases
hexokinase
G-6-P
F-6-P
F-1,6-diPase
glycogen synthetase
F - 1,6 -diP
PFK
glucose
insulin
glucagon
epinephrin
cortisol
triose
amino acids
pyruvate
proteins
Krebs
cycle
acetyl CoA
fats
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Physiology of Metabolism, Food Intake
and Energy Balance
T3-T4 (low)
TSH (low / normal)
TRH mRNA (low)
UC proteins (low)
TRH-induced
TSH release (high)
TRH release (low)
SS inhibits TSH release
Insulin (low)
Glucagon (high)
Cortisol (high)
Epinephrine (high)
LH/FSH (low)
Leptin (low)
Cas, NPY, aMSH, arcuate
thermogenesis (low)
energy expenditure (low)
(fasting & hibernation)
PVN, link to ME and ANS
POA,
t°C/F
integration
site
ANS, neuronal
link to thyroid
ME, link to AP
Thyroid, control of
Na/K ATPase and
uncoupling proteins
changes in the set - point of the control system affect the overall function of the system !
Physiology of Metabolism, Food Intake
and Energy Balance
Glucose availability
glucose sensitive
neurons in brain stem
(NTS, AP), hypothalamus (VMH-DMH,PVN)
and hepato-portal
circulation
(to NTS).
Inputs to
a Central
Integrator
Sensory stimuli
to NTS, PBN and cortex.
∑
S
E
Body energy
stores
leptin in ARCVMH
The PVN is a main central integrator involved in neuroendocrine control of food intake
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Physiology of Metabolism, Food Intake
and Energy Balance
Inputs to
a Central
Integrator
Long - term
Insulin, Leptin
cortisol,
T3-T4,
GH / IGF1
∑
S
E
Short - term
Glucose, Proteins and Fats
GI volume and GI peptides
The PVN is a main central integrator involved in neuroendocrine control of food intake
Physiology of Metabolism, Food Intake
and Energy Balance
Obesity & anorexia are only the extremes of the central integrators’
playfield
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Physiology of Metabolism, Food Intake
and Energy Balance
nutrient excess may lead to
oxidative stress, and to an
inflammatory and unfolded
protein responses in SER.
Metabolic
Dysfunction
accumulation of longchain fatty acyl-CoA
usually oxydized in
mitochondria to ATP.
low mitochondrial activity
induced by nutrient excess.
activation of signaling paths
promoting inflammation as
for example inhibitor NF-K-ß.
∑
S
E
inflammation blocks insulin action
(eg. IRS-PI3K) & rises insulin and
leptin resistance to limit intake.
a similar effect of inflammation on ß-cells
might explain ß-cell exhaustion & DM type 2.
a similar effect of inflammation on the IRS-PI3K path of endothelial cells
decreases the generation of NO, a widespread vasodilator signal.
Dysfunction of energy homeostasis and hypertension
might arise from exposure of body cells to nutrient excess
Recitation question # 07
The seventh recitation question attempted to “force” you to think on two
metabolic control systems operating simultaneously on a common integrating
system, the hypothalamic paraventricular nucleus (PVN). Your answer should
follow the (a,b,c,d) sub-question structure you have used before (see next
slide)."
If you can not write an idea into a single sentence,"
you probably have not yet understood the material.
10
Recitation question # 07
The seventh recitation question attempted to “force” you to think on two
metabolic control systems operating simultaneously on a common integrating
system, the hypothalamic paraventricular nucleus (PVN). Your answer should
follow the (a,b,c,d) sub-question structure you have used before (see next
slide)."
If you can not write an idea into a single sentence,"
you probably have not yet understood the material.
How do you think about this
type of questions
PVN
efferent
pathways
afferent
pathways
list here
characters
events and
processes
S
E
-Fb
pathways
list here
characters
events and
processes
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How do you think about this
type of questions
PVN
(sub-centers ?)
define
afferent
pathways
list
digestion
related
sensory
elements
list
temp.
related
sensory
elements
define
efferent
pathways
S
E
define
-Fb
pathways
list
digestion
related
motor
elements
list
temp.
related
motor
elements
How do you think about this
type of questions
PVN
Select the options you
understand the best and
answer the four subquestions (a,b,c,d).
define
afferent
pathways
list
digestion
related
sensory
elements
list
temp.
related
sensory
elements
S
Always attempt to go from
the widest answer to a
very specific one, when
selecting elements and
answering the subquestions.
define
-Fb
pathways
define
efferent
pathways
E
list
digestion
related
motor
elements
list
temp.
related
motor
elements
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A VERY, VERY LARGE HINT
•  Think on an homeostatic control system.
Which are its theoretical components and
how are they related.
•  Think on the role of a PVN integrator and
control of thyroid, GI and ANS functions.
•  What is the easier way to modify the level
at which a control system is working ???
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