2 - Obesity and Nutrition Flashcards
White adipose tissue (WAT) functions as a ______ organ
endocrine!
secretes adipokines that function like hormones with autocrine/paracrine/endocrine actions to refulate energy homeostasis
How is adipose tissue type classified?
by color
White (WAT)
Brown (BAT)
Beige (bAT)
Most adipose tissue is classified as:
WAT
Which is visceral WAT more likely to do if excess fat is generated:
hypertrophy or adipogenesis?
hypertrophy
Which subcutaneous fat more likely to do if excess fat is produced:
Adipogenesis or hypertrophy
adipogenesis
Which is harder on your body: hypertrophy or adipogenesis?
Hypertrophy
Adipogenesis leads to smaller adipocytes with greater fat storage capacity
Produces more leptin, less adiponecting, and fewer inflammatory mediators
Has a lower associated with insulin resistance
The complications of obesity are in large part due not just to the amount of fat in the body, but _______
where the fat is stored in the body
What effect does estrogen have on fat storage?
Enhances the deposition of fat in the SubQ tissue, inhibits it in visceral tissue
Why are premenopausal women more likely to have peripheral fat, while menopausal women and men are more likely to have visceral fat?
Estradiol increases alpha 2 adrenergic receptors in SQ tissue but not visceral
Alpha receptors outnumber beta receptors, so lipolysis is lower in SQ tissues
The reverse is true in the visceral tissue
hence, women with estradiol burn less SQ fat than visceral fat
Brown adipocytes have ______ vacuole(s)
White adipocytes have ______ vacuole(s)
multiple
one
Why are BAT brown?
Large numbers of mitochondria
Describe how BAT increases body heat
Activation of Uncoupling protein 1 (UPC1) promotes mitochondrial respiration
dissipates chemical energy as heat from increased flucose and FFA oxidation
What stimulates BAT heat generation?
exposure to cold
SNS
catecholamines
T3
How is BAT related to BMI and age
inversely
the higher the BMI, the less BAT
Production of bAT is called:
“the beiging of WAT”
Develops in response to chronic exposure to cold, with exercise
This is a reversible adaptation
Which brain nucleus regulates food intake and metabolism?
Arcuate (hypothalamus)
Neurons that promote appetite are called ______ neurons and are stimulated by ______
Neurons that inhibit appetite are called ______ neurons and are stimulated by _________
orexigenic
orexins
anorexigenic
anorexins
Leptin is a product of the _____ gene and is expressed by _____ cells
Ob
Adipocyte
High leptin levels inhibit ______ and stimulate _______
Low leptin levels inhibit _____ and stimulate _______
orexigenic, anorexic
anorexic, orexigenic
What is leptin resistance?
Leptin levels increase with the number of adipocytes, leading to downregulation of receptors
What does leptin resistance lead to?
Overeating
Hyperglycemia
Hyperinsulinemia
Hyperlipidemia
Inflammation
What all does leptin regulate?
Satiety
Hepatic gluconeogenesis
insulin sensitivity
glucose and lipid metabolism in the liver, muscles, and adipose tissue
Leptin resistance leads to ______ resistance
insulin
What is the role of adiponectin in obesity?
produced by visceral adipose, cardiomyocytes and skeletal muscle
insulin-sensitizing
anti-inflammatory
Plasma levels decrease with visceral obesity
Why is adiponecting made in cardiomyocytes?
It is cardioprotective
decreased levels associated with CAD
Where is Ghrelin produced?
What does it do?
In the stomach mucosa in response to hunger
stimulates food intake
induces metabolis changes leading to increased weight and fat mass
Ghrelin stimulates the release of ______ hormone
GH
What decreases Ghrelin levels?
Increased serum FFAs
How does obesity related to ghrelin?
Causes ghrelin resistance
In obese people, ghrelin does not decrease after eating. Instead, it stays at a steady elevated level, with only slight dips after meals
CCK levels are _____ in obesity
decreased
Obesity produces a chronic state of _____ in WAT
inflammation
What are other terms for visceral obesity?
intraabdominal
central
masculine
What are other terms for peripheral obesity?
subcutaneous
gluteal-femoral
feminine
What is normal weight obesity?
Normal body weight and BMI with >30% body fat
What is cachexia?
Cytokin-induced malnutrition
physical wasting
What is refeeding syndrome?
In severely malnourished patients, their insulin levels are extremely low
In addition, their plasma levels of electrolytes plummet, so K/Mg/Phos move out of the cell and into the plasma
When feeding starts up again, the cells is hypersensitive to insulin, and starts sucking all those electrolytes back in
Can lead to perilously low blood levels
How many calories are liberated from 1g of the following:
Carbohydrates
Fat
Proteins
4
9
4
What are partial proteins?
Proteins that contain inadequate amounts of essential amino acids
Proteins derived from meats are usually ______
Proteins derived from vegetables are usually _____
complete
less complete/partial
In vegetarian diets, the combination of ______ and _____ provides all the essential amino acids
corn
legumes
The respiratory quotient for carbs is 1
the respiratory quotient for fats is 0.7 and proteins are 0.8
Why?
When carbs are metabolized with oxygen, exactly one CO2 molecule is formed for every molecule of O2 consumed
for fat and proteins, a portion of the oxygen metabolised is required to combine with the excess hydrogen atoms, so less CO2 is produced
Describe the respiratory quotient directly after a mixed meal?
8 hours later?
approaches one, as the body prioritizes carb metabolism
All the carbs have been used or stored, and respiratory quotient approaches 0.7 (fat metabolism)
In severe diabetes, what would the respiratory quotient most likely be?
0.7, fat metabolism
What percentage of the average protein is nitrogen?
16%
What does it mean if someone has a negative nitrogen balance?
their body stores of protein are decreasing daily
What percentage of ingested energy actually reaches the cells?
27%
Which area in the brain contains the hunger and satiety centers?
The hypothalamus
The _______ of the hypothalamus serve as a feeding center
lateral nuclei
The ______ of the hypothalamus serves as a satiety center
ventromedial
inhibits the feeding center
Destruction of the ventromedial nucleus of the hypothalamus would cause:
voracious eating, up to four times normal
Are the following hormones anorexigenic or orexigenic?
Leptin
Serotonin
Cortisol
Insulin
CCK
Ghrelin
Leptin - Anorexigenic
Serotonin - Anorexigenic
Cortisol - Orexigenic
Insulin - Anorexigenic
CCK - Anorexigenic
Ghrelin - Orexigenic
What suppresses appetite in the short term, preventing over eating?
- Gastrointestinal filling sends stretch receptors via the vagus to suppress feeding centers
- CCK activates receptors on local sensory nerves in the duodenuum, sends via the vagus
- Oral receptors meter food intake (less of an impact than GI filling)
How does ghrelin affect feeding?
increases feeding
How does the hypothalamus sense energy storage?
leptin produced by adipocytes
Stimulation of leptin receptors in the CNS leads to:
- hypothalamus suppresses AGRP
- Hypothalamus stimulates POMC
- hypothalamus increases CRH
- decrease insulin secretion from pancreas
What is the calculation for BMI?
kg/m2
What kind of tumor is associated with progressive obesity?
hypophyseal tumor that encroach on the hypothalamus
Naltrexone is used in conjunction with _______ to reduce obesity
buproprion
Crazy!
what is inanition?
opposite of obesity
extreme weight loss
What is a vitamin?
organic compound needed in small quantities for normal metabolism that can’t be manufactured in the cells of the body
What disease is caused by thiamine deficiency?
Beriberi
What is the pathogenesis of berberi?
thiamine deficiency caused decreased utilization of pyruvic acid and some amino acids by the tissues
increases utilization of fats
What are the major effects of Beriberi?
- lesions of the CNS and PNS (the brain is using ketone bodies instead of glucose, which causes swelling and inflammation)
- cardiac failure and vasodilation
- indigestion, severe constipation, anorexia, gastric atony, hypochlorhydria
Why is riboflavin’s big role in body?
Required in the electron transport chain
Name the B Vitamins
- Thiamine
- Riboflavin
- Niacin
- Pantothenic Acid
- Pyridoxine
- Folic Acid
- B12
What is the function of niacin in the body?
nicotinic acid
NAD and NADP -> ETC
Niacin deficiency is called _____ and results in people on a ______ diet
pellagra
corn
(corn lacks tryptophan, which can be convertered to niacin)
What is the role of Vitamin B5?
What does a deficiency cause
Pantothenic Acid = CoA
depressed metabolism of carbs and fats
What is the role of pyroxidine in the body?
Vit B6
transaminatio of amino acids
What does Vitamin B12 deficiency cause?
pernicious anemia
demyelination of the large nerve fibers in the spinal cord
What are the major functions of B12 in the body?
reduces ribonucleotides to deoxyribonucleotides, facilitating gene replication
- promotion of growth
- promotion of RBC formation and maturation
What is the role of Vitamin B9 in the body?
Folic Acid
synthesis of purines and thymine, which are required for DNA synthesis
One of the most significant effects of Folic Acid deficiency is:
macrocytic anemia (almost identical to pernicious anemia)
What are the consequences of a Vitamin C deficiency?
weakens collagen fibers
causes scurvy
How long does it take to get scurvy?
20-30 weeks
What are the effects of scurvy?
Fucked up collagen:
- failure of wounds to heal
- cessation of bone growth
- blood vessel walls become extremely fragile
Vitamin E plays a protective role in the prevention of:
oxidation of unsaturated fats
Where is vitamin k synthesized?
bacteria in the colon
What usually causes Vit K deficiency?
problems with gut flora
almost never caused by a decreased intake
______ is the major anion of intracellular fluid
phosphate
Zinc is an integral part of which enzymes?
carbonic anhydrase
lactic dehydrogenase
How does fluorine make teeth stronger
It doesn’t. It suppresses the cariogenic process.
