Endocrine Deck 4 Flashcards
what is energy expenditure determined by?
resting (basal) metabolic processes (energy needed in a physically inactive state)
White adipose fat
most abundant in the body
responsible for many of the functions of fat
found deep within the body (visceral fat) and in the periphery as subcutaneous fat. Increases in visceral fat predominantly around the intra-abdominal cavity (belly fat) are associated with increased complications such as cardiovascular and diabetes mellitus risk.
what are some of the key functions of fat
storage of excess calories as an energy reserve. Adipokines (hormones and cytokines) released by adipocytes (fat cells) also regulate metabolism and activate immune processes.
Excesses of white fat cause dysregulation of these multiple adipokines
aging and fat
With aging, gonadal and growth hormone naturally declines, resulting in an increase in visceral fat in men, while in women, decreases in estrogen (usually due to menopause) and growth hormone contribute to increases in visceral fat.
White fat can become __________ __________
Beige fat
Beige fat is
an energy-expending type of fat
Brown fat
is considered a good fat and primarily regulates energy usage, particularly maintenance of warmth in newborns, and usage peaks around puberty. Brown fat expends energy like beige fat. The amount of brown fat decreases with age but continues to remain metabolically active and is stimulated with exposure to cold weather
Brown fat is located in
upper torso in the neck and clavicular area
The more active the brown fat the…..
lower the BMI and body fat percentage
What type of fat do leaner individuals have more of
Brown fat
Body weight and fat stores are regulated by the
central and peripheral nervous system
From periphery to metabolism… (orexigenic)
afferent signals from the periphery regarding food needs and fuel use -> CNS -> orexigenic neurons in hypothalamus stimulated ->decreased metabolism and mechanisms to increase calories by promoting appetite and stimulation of eating
From periphery to metabolism (anorexigenic)
afferent signals from the periphery regarding food needs and fuel use -> CNS ->anorexigenic neurons in hypothalamus stimulated -> , increase metabolism and suppress appetite and eating.
how do signals lead to overeating
The hypothalamus also connects with areas of the cortex that are associated with memory, pleasure, and reward, and these areas can be activated by food and the feeling of satiety. Activation of these areas can override physiologic intake and energy expenditure stimuli leading to overeating, or the desire for only certain foods
what is leptin?
a key hormone that is primarily secreted by white fat adipocytes; its role is to send signals to the brain regarding the adequacy of energy reserves.
what happens to leptin levels when a person overeats?
leptin levels increase dramatically
what happens to leptin levels when a person fasts?
Leptin levels decrease
Leptin levels are correlated with ….
body fat mass, and the levels increase in proportion to the number of adipocytes
Leptins key action is
decreasing food intake
Leptin and obesity
high levels in obese individuals are ineffective in suppressing appetite. This ineffective response is due to resistance or tolerance to the effects of leptin. The reason for the development of resistance is unclear. There is also a single gene defect that causes leptin deficiency and obesity.
what are orexins
GI hormones that are either associated with appetite stimulation and increases in food intake
What are anorexins
GI hormones that are associated with appetite suppression and inhibit food intake
What is Ghrelin?
produced in the stomach and duodenum
stimulates growth hormone and food intake
increase when a person is fasting
Decrease after eating
what food type suppresses ghrelin the most
carbs followed by protein and lipids
diet and exercise related weight loss and ghrelin
Diet and exercise-related weight loss causes increases in ghrelin as a compensatory mechanism, thereby making maintenance of weight loss challenging.
• Glucagon-like-peptide-1
hormone produced in the intestines
Stimulation causes insulin release, slows gastric emptying, and suppresses appetite
Levels may be low in obese individuals
• Cholecystokinin:
secreted by the intestines
causes gallbladder release of bile and release of pancreatic enzymes and insulin and slows gastric emptying
Levels may be low in obese individuals.
• Pancreatic polypeptide and peptide YY 3-36:
produced by the pancreatic polypeptide cells
inhibit gastric motility, cause satiation, and decrease appetite
Levels may be low in obese individuals
• Oxyntomodulin:
found in the colon
causes appetite suppression
• Amylin
released from the beta cells
synergistic relationship with insulin
glucose control by suppressing glucagon, delaying gastric emptying, and increasing satiety.
Levels may be increased in obesity, but there is resistance to the effects.
obesity and inflammation
chronic, low-grade inflammatory state created by adipocytes in white fat
Immune cells in the white fat release various inflammatory cytokines
excess fat of obesity is associated with various biomechanical disorders such as
gastroesophageal reflux disease, osteoarthritis, sleep apnea, and urinary incontinence
abnormal menses and infertility
what cancers are linked with obesity
colon, pancreatic, breast, and endometrial cancer
Approximately 40% of all cancers diagnosed are attributed to obesity and overweight
