ABOM Review Flashcards
3 afferent pathways in energy balance
- Environmental sensing (GI , sensory organs)
- Metabolic needs (liver, muscle, bone)
- Energy stores (adipose, liver, muscle)
Leptin: what is the primary problem in obesity? are levels high or low? binds to ? anorexigenic or orexigenic?
leptin resistance
high
leptin receptor in hypothalamus
anorexigenic
Adiponectin:
low or high in obesity?
anorexigenic or orexigenic?
what induces expression of adiponectin?
low
anorexigenic
PPAR-Y agonizts - TZDs
effects of adiponectin on skeletal muscle, liver, cardiac muscle
skeletal muscle: increases glucose uptake, increases fatty acid uptake, increases mitochondrial mass and oxidative capacity
liver: insulin-like and insulin sensitizing effects
cardiac muscle: remodeling, vasodilation, anti-inflammatory, anti-atherosclerotic
low adiponectin is independently associated with
t2DM, MetS, fatty liver, cad, endothelial dysfunction, MI, chf, htn
3 adipokines are
secreted by
leptin adiponectin resistin
adipokines
5 incretins are
secreted by
GLP-1 PYY ghrelin GIP oxyntomodulin intestinal L cells, stomach fundus
GLP-1 (glucagon like peptide 1) :
anorexigenic or orexigenic
high or low in obesity
sites of action/ function
anorexigenic low (post prandial) pancreas - increases insulin release gut delays carb absorption and decreases gastric secretion/ motility brain increases satiety
how does GLP-1 increase satiety in brain?
inhibits NPY
Peptide YY (PYY):
anorexigenic or orexigenic
high or low in obesity
sites of action/ function
anorexigenic
low (post prandial)
afferent vagus and hypothalamus
increases satiety and stimulates glucose-mediated insulin secretion
what is the only circulating orexigenic hormone
ghrelin
ghrelin: stands for secreted by peaks when function high or low in obesity before meals, post prandially suppressed longest by
growth hormone release inducing peptide fundus before meals stimulate food intake low before meals (appropriate) , post prandially less suppression protein
DPP4 degrades what
GLP-1 and PYY
pharmacologic GLP-1 agonists are
exenatide, liraglutide
pharmacologic DPP4 inhibitors are
sitagliptin
satiety factor secreted by pancreas
amylin, or islet amyloid polypeptide
pharmocologic actor on amylin
pramlintide
what is the first myokine?
action?
what stimulates it
irisin
stimulates browning of white fat, induces insulin secretion, leads to weight loss and improved glucose control
exercise and cold
what are the anorexigenic neurotransmitters released from first order neurons?
where are they located?
POMC (proopiomelanocortin) and CART (cocaine and amphetamine related transcript)
arcuate nucleus of hypothalamus
what are the orexigenic neurotransmitters released from first order neurons?
where are they located?
AgRP (agouti related peptide) and NPY (neuropeptide Y)
arcuate nucleus of hypothalamus
what stimulates POMC/ CART
insulin, leptin
what stimulates AgRP/ NPY
ghrelin
what do POMC/ CART stimulate?
effect?
MC4R receptors of paraventrcular nucleus (PVN) and lateral hypothalamus
decreased food intake, increased energy expenditure
what do AgRP / NPY stimulate?
inhibit?
effect?
Y1R receptor on neurons in paraventricular nucleus (PVN) and lateral hypothalamus
MC4R receptors in PVN and LH
MC3R receptors in first order neurons in arcuate nucleus
increased food intake, decreased energy expenditure
how does activation of melanocortin receptor (MC4R) cause increased energy expenditure
increased brown adipose tissue thermogenesis
increased white adipose tissue lipolysis
increased locomotor and myocardial activity
increased muscle glycogenolysis, glucose and fatty acid oxidation, and protein synthesis
noradrenergic neurons originate in
locus coeruleus, lateral tegmental field of hypothalamus
what causes vagal efferent activation?
anatomy?
effect?
low leptin signaling, persistent orexigenic signaling (ghrelin)
lateral hypothalamus and paraventricular nucleus 2nd order neurons stimulate medial longitudinal fasiculus and dorsal motor nucleus of the vagus
increased energy storage
mechanisms of vagally mediated increased energy storage?
reduced HR and o2 consumption
increased peristalsis and pyloric opening
increased post prandial insulin secretion and fat deposition
increased glucose and FFA uptake into adipose tissue and increased insulin sensitivity
adult DRI for fat
20-35%
adult DRI for carbs
45-65%
adult DRI for protein
10-39%
0.8 g/kg/d
diet to lower TG
atkins
diet to decreased cvd, dm
ornish, vegan
diet to decrease BP
dash (high carb, <25%fat, 2-3 low fat dairy, high in ca, mg, k fiber, low in meats, sweets, snacks
diet to decrease cvd
mediterranean
diet to decrease seizures
ketogenic
diet to treat short gut and malabsorption
medium chain triglycerides
which is more important , diet type or adherence?
adherence
does macronutrient mix predict weight loss
no
dietary strongest evidence of treatment benefit (wt loss)
meal replacements
what is more important than caloric intake
energy density
very low calorie diets require how much protein?
1.5 g/kg/d
contraindications to very low calorie diet
renal insufficiency, type I dm, esld, pregnancy, pancreatitis
side effects of very low calorie diet
gallstones, constipation, fatigue, coldness, hair loss, irregular menses
weight regain following VLCD
40-50% within 1-2 years
B1 thiamine (function, findings, deficiency)
pyruvate dehydrogenase, neuropathy,cardiomegaly, beri beri, wernicke korsakoff
B2 riboflavin (function, findings, deficency)
FAD, mouth/tongue pain, chelitis
B3 niacin (FFD)
NAD, desquamative dermatitis sun exposed, dementia, diarrhea, death, pellagra
B6 pyridoxine
transamination, polyneuropathy, anemia
B12 cobalmin
methyltransfer, neuropathy periph/central, pernicious anemia
folate
dna synthesis, glossitis, stomatitis, megaloblastic anemia
vitamin C
collagen synthesis, perifollicular petechiae, poor wound healing, scurvy
calcium, phos, mg affected area, deficency
bones, enzymes, conduction, osteopenia, arrhythmia, sz
zinc
metalloenzymes, growth, acrodermatitis enteropathica
copper
metalloenzymes, menkes kinky hair
selenium
glutathione peroxidase, kershan disease, cardiomyopathy
chromium
glucose tolerance, glucose intolerance
what is refeeding syndrome?
who is at risk?
depletion phos, mg, K with feeding causing heart failure
alcoholics, NPO 7 days, bariatric surgery postop, elderly, esld, anorexia
most common nutrient problems after bariatric surgery
less common
ca, vitamin D, iron, b12
thiamine, zinc , copper
