Physiology

Question 1

Cognitive control of eating

Answer 1

frontal lobe
cingulate cortex
inferior frontal cortex

Question 2

Attention to external food cues

Answer 2

frontal
parietal
occipital
+visual areas

Question 3

Amygdala

Answer 3

activates to food cues even when not hungry

Question 4

Hippocampus

Answer 4

-responds to memory and experiences
-can override hunger and satiety based on food cues

Question 5

Reward center sites receiving DA signals

Answer 5

-response to food cues (high cal, high fat)

Sup to inf:
1- dorsal striatum
2- nucleus acumbens
2- substantia nigra
4- VTA (ventral tegmental area)

Question 6

Homeostatic control of eating
-1o site
-cues
-controls

Answer 6

-primarily in arcuate nucleus
-responds to peripheral signals: 1- gut hormones, 2- adipose hormones, 3- nutrients
-controls appetite & E exp

Question 7

Orexigenic Pathway

Answer 7

= hunger

1. Ghrelin +stim, Leptin/insulin inhibit
2. 1st order neuron: AgRP/NPY in arcuate nucleus
3. Receptors: Y1, Y5, (**AgRP also blocks MC4R) ?blocks a-MSH to MC3R & MC4R
4. 2nd order neuron: __ in hypothalamus PVN
5. Increase food intake

Question 8

Anorexigenic pathway

Answer 8

= fullness

1. Leptin & insulin +stim
2. 1st order neuron: POMC/CART in arcuate nucleus
3. Receptors: MC4R, MC3R
4. 2nd order neuron: __ in hypothalamus in PVN
   ?aMSH
5. Reduced food intake & inc EE

Question 9

PNS signals
-duration
-vagus roles

Answer 9

-short-acting
-vagus
afferent (sensory input): regulate motility, glucose production, gut hormone secretion
efferent (output): hormones CCK, PYY, GLP-1, insulin

Question 10

E expenditure impacted by (5)

Answer 10

-ambient temp
-circadian rhythm
-nutrition
-inflammation
-reproductive state

Question 11

Central regulation of E exp (3)

Answer 11

1. SNS outflow -> NE -> thermogenesis by BAT
   *SNS also influenced by glucose, ins, lep, GLP-1
2. SCN produdes TGF-a –| locomotor via subparaventricular zone in hypothalamus
3. Orexin-A produced in hypothalamus –> locomotion, wakefulness

Question 12

Peripheral regulation of E exp (3)

Answer 12

1. Insulin & leptin signal amount of fat stores
2. Leptin –> locomotion to POMC neurons
3. IL-6 from muscle during exercise –> mobilize fat to provide E to mm

Question 13

Most variable component of TDEE

Answer 13

Activity-induced

Question 14

Adipocyte signals
1. Diff’n: fibroblast –> pre-adip
2. Mat’n: maturation
3. inhibition of proliferation

Answer 14

1. Diff’n:
   PPAR-g stimulated by
   -environmental factors
   -obesogenic meds
   -human ad-36
2. Mat’n
   insulin, GFs, glucocorticoids
3. SNS inhibits prolif

Question 15

-Normal amount of visceral fat
-Least metabolically active

Answer 15

-10%
-lower body subQ

Question 16

White vs Brown:
-shape
-mito
-other

Answer 16

White:
-spherical
-low mito
-TG droplets

Brown:
-polygonal
-high mito (color from iron)
-multiple lipid droplets

*critical for body temp
*adaptive thermogenesis in resp to food or cold (nonshivering via UCP1 in mito), burns fat and glucose
*more nerves than white, mediated by hypoth & SNS innervation (NE)

Question 17

Beige adipose

Answer 17

?aka Brite

-chars of both white and brown, UCP-1 in mito
-PET+ areas (supraclav, suprarenal, pericard, paraAo, panc, kids, trach)
-within WAT

“Beiging” occurs due to (–> = theories)
diet –> high fat feeding ↑ UCP-1, ?polyuns ↑↑, high protein (esp. whey), capsaicin
exercise –> irisin from myokines ↑ UCP-1 in WAT
pre/post biotics
drugs
plant-based bioactives
adipokine
insulin/leptin –> POMC –> beign WAT

Question 18

Anabolic & Catabolic Cycle

Answer 18

Anabolic (= Orexogenic, need nutrients to build):
↓ lep & insulin = E deficit
disinhibits (↑) NPY/AgRP, ↓ POMC/CART
↑ food intake, ↓ met rate
Food ↑ insulin & leptin = +E balance
↓ NPY/AgRP, ↑ POMC/CART
↓ food intake, ↑ met rate

Question 19

Anabolic pathway vs. Catabolic pathway signaling in ARC

Answer 19

An = Orexigenic (NPY, AgRP)
Cat = Anorexigenic (POMC/CART)

Question 20

Most metabolically active adipose tissue anatomically

Answer 20

SubQ abdominal (upper body)
-lower body least active

Question 21

Visceral adipose hormones (5+)

Answer 21

adiponectin
leptin
TNF
resistin
IL-6
and more…

Question 22

Pro-inflammatory adipokines

Answer 22

leptin
visfatin
apelin
chemerin
resistin

Question 23

Anti-inflammatory adipokines

Answer 23

adiponectin
omentin
vaspin

Question 24

Lipokines from adipose

Answer 24

palmitoleate
diHOME ?
FAHFA species

*regulate metabolism
↑ by diet, exercise, cold exp

Question 25

RNA adipose-derived extracellular vesicles

Answer 25

-endocrine messengers: imm mod, ins sens, T cell diffn -paracrine: ↑ lipogenesis *modulated by hypoxia, sat fat, pro-infl cytokines

Question 26

Leptin -source -receptor -functions

Answer 26

** primarily WAT ** receptor in hypothalamus ** PRO-inflammatory ** Satiety (hypothalamus via NPY & POMC ** Regulates lipid homeostasis ** ↑ EE on CV system and thermogenesis via hypothalamus -↑ SNS tone (directly and via aldo -> SNS -> ang II --| ins receptors) -Modulates glucose homeostasis periph and centrally -↑ ins sens -inhibits hCG-med testost -↑ ov steroids (few other things on slide)

Question 27

Adiponectin -source -receptor -functions

Answer 27

** adipocytes & skeletal muscle ** receptor throughout body ** ANTI-inflammatory ** Ins sensitizing (↑ glu uptake, ↓ liver glucose output) ** CV: ↓ early athero and uangiopathy - ↓ mm and liver TG deposits (few other things on slide)

Question 28

Ghrelin -source -receptors -role

Answer 28

-produced by stomach (also epsilon cells of panc) -receptors widespread but for eating primarily in hypothalamus -Orexigenic (initiate eating, ↑ meal size) --> adrenal cortisone; GH --| GnRH, glucose-stim insulin secrn by panc, thyroid hormone effects also sleep/wake rhythms, taste sensation, ↓ ins resistance ** only peripheral hormone related to hunger

Question 29

GLP-1 -source -receptors -role

Answer 29

-L-cells in sb & colon in response to food intake -receptors in hypothalamus & gut -ANorexigenic, SHORT-acting -↓ gastric emptyhing ↑↑ after bypass small bowel

Question 30

Additional satiety hormones (7)

Answer 30

Intestine: -CCK -PYY -OXM (oxyntomodulin) -enterostatin -GIP (gluc-dep ins-tropic polypep) Panc: -amylin -insulin

Question 31

Direct vs Indirect calorimetry

Answer 31

Driect: -heat loss/production measured in enclosed chamber -60% of food energy liberated as heat, 40% stored as ATP Indirect: -measuring heat production via CO2 cons & O2 prod -desktop systems (doubly labelled water for research only)

Question 32

Metabolism across lifespan -highest -adults -

Answer 32

-infants highest per lb. (50% higher than adult) ... ↓ 3% per year until 20 yo, then levels off... -adults STABLE even in preg and post-partum -age 60 yo ↓ 0.7% per year

Question 33

Carb metab

Answer 33

↑ insulin immediate energy or stored as glycogen or liver full --> stored as fat

Question 34

Protein metabolism

Answer 34

↑ insulin if AA's not needed --> goes to liver --> gluconeo if liver full, stored as adipose

Question 35

Fat metabolim

Answer 35

Emulsificaion ↑ insulin Send throughout body OR stored in adipocytes

Question 36

Sleep and Metabolism

Answer 36

-metab ↓ 15% during sleep -lowest glucose metab in NREM & intermed REM -GH highest in slow-wave sleep -↑ cortisol secod half of sleep (primary REM) ↑↑ leptin ↓ grehlin during latter part of night

Question 37

Circadian Alignment -location -influences -hormones -deprivation

Answer 37

*synchronization of 24 cycle needed to have stable sleep & EE -master circ clock in SCN -EE & food can influence clock in SCN -hormones with circh rhythm: leptin, insulin, cortisol -sleep deprivation ↑ Ghrelin Orexin -? link btw sleep & metab, -nfluenced by leptin, ghrelin, glucose

Question 38

... addendum slides not done, p 38-42 ... adipokines, satiety & hunger hormones)