Pathophys Flashcards
Benefits of Exercise
Increased insulin sensitivity, reduction in BP, improved lipids, reduction in inflammation in synovial fluid, and increased lean muscle mass
FAST TWITCH (muscle fibers)
Type II - Energy from short term glycolysis, creates forceful contractions, suited for short-term sprint activities requiring forceful muscle contraction
SLOW TWITCH (muscle fibers)
Type 1 - abundant mitochondria, energy from oxidative metabolism, fatigue resistant, suited for prolonged PA, slow contraction and increased oxidation (SO)
GLP-1
Glucagon-Like Peptide 1 - produced in L cells and secreted in response to food (c, p, f); Glucose-dependent insulin secretion, suppresses glucagon, delayed gastric emptying and increased satiety, reduced appetite
*GLP-1 levels increase significantly after bypassing the proximal small intestine thus DM improves immediately after gastric bypass
CCK
Cholecystokinin - produced in i cells and secreted in response to fat and protein ingestion, short acting; slows gastric emptying, reduces appetite
Small Intestine Hormones (ANOrexic)
CCK, GLP, OXM, PYY
Factors that Reduce Ghrelin
Meals (Carbs suppresses fast, but rebounds fast; protein suppresses longer), Weight gain, Leptin, Gastric sleeve surgery
Factors that Increase Ghrelin
Fasting/prolonged fasting, Weight Loss, Stress/Sleep deprivation, Genetics/syndromes (i.e. Prader Willi)
OREXigenic Pathway (Hunger)
Ghrelin ==> NPY/AgRP in the CNS (also may reach brain from vagal nerve and nucleus tractus solitarius) ==> increase food intake and weight gain
Ghrelin
Growth Hormone RELease Inducing Peptide - only circulating OREXigenic gut hormone = hunger
Orexin A/Orexin B
Orexigenic - found in 2nd order neurons in lateral hypothalamus, stimulated by NPY and AgRP, increased arousal
MCH
Melanin Concentrating Hormone - orexigenic; 2nd order neurons in lateral hypothalamus, stimulated by NPY/AgRP; increases food intake, acts on higher order neurons to stimulate cognitive function for feeding, pleasure reward; inhibited by leptin
AgRP
Agouti-related Peptide - orexigenic, found in arcuate nucleus, with NPY, stimulated by ghrelin, inhibits MC3R, MC4R; inhibited by insulin, leptin, PYY, and serotonin; decreases energy expenditure, oxygen consumption
NPY
Neuropeptide Y; orexigenic, in arcuate nucleus, found with AgRP; most abundant central neuropeptide and most potent orexigen; stimulated by ghrelin, inhibited by insulin, leptin, PP, PYY, and serotonin
Anorexigens - reduce intake
Propiomelanocortin (POMC), Cocaine amphetamine regulating transcript (CART), a-melanocyte stimulating hormone (a-MSH), Brain derived neurotrophic factor (BDNF), Serotonin
Orexigens (increase intake)
Neuropeptide Y (NPY), Agouti-related protein (AgRP), Orexin-A, Orexin-B, Melanin-concentrating hormone