Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIOL 432 Final > Adipose and Obesity > Flashcards

Adipose and Obesity Flashcards

1
Q

How is obesity assessed? What is the occurrence?

A
  • assessed by BMI (body mass index)

- more than 60% of adults in US

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the exceptions to BMI?

A
  • correlates with amount of body fat (not direct measure)

- athletes and pregnant women

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does body shape correlate with health risk?

A
  • apple shaped: central or visceral-abdominal obesity (increased cardiovascular risk)
  • pear shaped: gluteal-femoral obesity (lower risk)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How is peripheral energy status signalled to the brain?

A
  • by fat-derived hormone leptin

- somewhat insulin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What gut-derived factors influence appetite behaviour?

A
  • ghrelin
  • peptide YY
  • glucagon-like peptide 1
  • cholecystokinin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How does the brain and liver impact appetite regulation?

A
  • brain cannot metabolize fatty acids (detect only glucose levels)
  • signal to brain via vagus nerve
  • liver metabolizes glucose and fatty acids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is leptin? What does it do? How?

A
  • cytokine like hormone secreted by adipose tissue
  • decreases food intake and increases metabolic rate
  • primariy by inhibiting neuropeptide Y secreting neurons in arcuate nucleus of hypothalamus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the Ob and Rb mice?

A
  • Ob gene: mutation that prevents production of leptin
  • Rb gene: mutation of leptin receptor
  • mice have obesity and low metabolic rates
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is often found in people with obesity?

A
  • insulin resistance

- with respec to visceral adiposity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What do visceral adipose cells produce?

A
  • significant amounts of proinflammatory cytokines
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What do proinflammatory cytokines do?

A
  • disrupt normal insulin action in fat and muscle cells

- may be a major factor in causing the whole-body insulin resistance in patients with visceral adiposity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The hypothalamus receives signals from brainstem to ARC where neurons release?

A
  • orexigenic neurotransmitters: NPY and AgRP (activate appetite, activated by ghrelin)
  • anorexigenic neurotransmitters: POMC and CART (inhibit appetite, activated y CCK, PYY, GLP-1, leptin)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is NPY?

A
  • neuropeptide Y
  • orexigenic substance
  • most powerful appetite enhancer
  • co-expressed with AgRP
  • both released by negative energy balance (low leptin, hypoglycemia)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is AgRP?

A
  • agouti-related peptide
  • orexigenic substance
  • high levels in obesity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is POMC?

A
  • proopiomelanicortin
  • anorexigenic substance
  • melanocortins decrease food intake
  • mutations in R = obesity, hyperphagia, hyperinsulinemia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is CART?

A
  • cocaine and amphetamine-regulated transcript
  • anrexigenic substance
  • colocalized with POMC neurons
  • role in decrease food intake complex
17
Q

What is CCK?

A
  • cholecystokinin
  • release from gut when nutrients in lumen
  • CCK-1R on vagus nerve - indicates fullness
  • infusion of CCK3 - decrease meal size
18
Q

What is PYY?

A
  • peptide YY
  • released from L-cells
  • correlates with ingested calories
  • infusion = decrease food intake and increase intervals between meals
  • deficiency seen in obesity
19
Q

What is GLP-1?

A
  • glucagon-like peptide-1
  • infusion decreases food intake and body weight
  • agonist extendin 4
20
Q

What does leptin inhibit and stimulate?

A
  • inhibits food intake, decreases appetite
  • inhibits NPY and AgRP neurons
  • stimulates POMC and CART neurons
21
Q

What are some features of the leptin receptor?

A
  • belongs to the cytokine R family, signals through STAT3
  • 6 subtypes
  • found in hypothalamus arcuate nucleus
22
Q

How are obesity and leptin linked?

A
  • most obese people are insensitive to leptin

- mutations in leptin gene (Ob) or its receptor (Rb)

23
Q

Where is ghrelin produced? How does it’s level fluctuate?

A
  • produced in oxyntic glands of stomach

- circulating levels increase before and decrease after a meal

24
Q

What does ghrelin stimulate?

A
  • stimulates appetite: by stimulating NPY and AgRP and inhibiting POMC neurons
  • stimulates release of GH
25
Q

What is the receptor of ghrelin?

A
  • growth hormone secretagogue receptor

- found in hypothalamus and pituitary

26
Q

What are the circulating levels of ghrelin like in anorexic patients? Obesity?

A
  • anorexic: levels elevated

- obesity: levels low

27
Q

What is obestatin?

A
  • from proghrelin precursor
  • decrease food intake
  • possible treatment for obesity
28
Q

In addition to appetite regulation, what other effects does leptin have?

A
  • decrease intracellular lipid in muscle and liver
  • decrease insulin sensitivity and secretion
  • regulate bone resorption
  • low levels inhibit reproduction, thyroid thermogenesis and immune resp
29
Q

What effects does adiponectin have?

A
  • increase insulin sensitivity, fa oxidation, glucose uptake and decrease gluconeogenesis
  • anti-inflammatory
  • targets liver and muscle
  • obesity: low concentration
30
Q

What are the effects of adipocytokines?

A
  • tumor necrosis factor and interleukin
  • pro-inflammatory
  • associated with insulin resistance
  • increased levels in obesity
31
Q

What are the effects of resistin?

A
  • decrease insulin sensitivity

- not in humans

32
Q

What other hormones are implicated with adipose as an endocrine organ?

A
  • estradiol

- angiotensinogen

33
Q

What are some of the diseases linked to obesity?

A
  • type II diabetes
  • coronary heart disease
  • stroke
  • some cancers
  • inflammatory conditions
34
Q

What three factors affect the occurrence of weight gain?

A
  • behaviour
  • genetics
  • age
35
Q

What kind of behaviours affect weight gain?

A
  • diet
  • physical activity
  • lack of sleep (increase ghrelin, decrease leptin)
36
Q

How do genetics affect weight gain?

A
  • influences how body burns calories and stores fat
37
Q

How does age affect weight gain?

A
  • physical activity decreases
  • GH (promotes lean muscle) decreases
  • E2 decreases
38
Q

How do excess carbohydrates affect insulin and trigylceride storage?

A
  • cause liver to become insensitive to insulin-inhibited glycogenolysis
  • hepatic glucose production, insulin increase, shifts oxidation to all carbs, leads to adipose fat storage
39
Q

How does leptin resistance lead to obesity?

A
  • triggers hyperphagia and weight gain
  • primary: genetic, mutations in leptin signalling
  • secondary: lack of response to high leptin levels (down reg)
  • leptin resistance correlated with insulin resistance

BIOL 432 Final (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions