177. Appetite Regulation Flashcards Preview

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Flashcards in 177. Appetite Regulation Deck (45)
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1
Q

__ levels have been shown to increase with weight loss, causing difficulty of maintaining weight loss

Also, amylin, CCK, and PYY levels have been shown to decrease with weight loss, thus satiety is more difficult to achieve

A

Ghrelin

2
Q
  1. Inhibiting neurons that coexpress the orexigenic hormones NPY and AgRP
  2. Stimulating neurons that coexpress the anorexigenic hormones alpha-MSH and CART
A

Leptin action in the arcuate nucleus

3
Q

Fasting plasma levels of __ are high in partients with anorexia nervosa and in subjects w/ diet-induced weight loss

A

Ghrelin

4
Q

Lesions to the __ hypothalamus induce excessive hunger

This area acts through MC4 receptor

A

Ventromedial

5
Q

What are times when fat stores need to be developed, thus when energy intake&raquo_space; energy expenditure?

A

Growth and development
Pregnancy
Recovery from an illness

6
Q

Peptide that is synthesized and released from endocrine L cells from the distal gut in response to food consumption
- particularly dietary fat

Levels increase w/in 30 minutes of nutrients reaching the distal gut

A

PYY

7
Q

One of the most potent orexigenic peptides peptides known

Hypothalamic __ mRNA levels are increased under conditions of acute food deprivation and chronic food restriction

A

NPY

8
Q

Neuropeptide that is abundantly present in the CNS

Provides a dominant inhibitory tone onto POMC

A

NPY

9
Q

Alpha-MSH’s receptor

When stimulated results in down-stream appetite control and energy balance

A

MC4R

10
Q

Hypothalamus responds with inflammation when pt is eating on a __

Inflammation may reduce responsiveness to normal neuropeptide signaling
- neuron damage

Causes a resistance to AgRP and POMC –> increase in body weight

A

High fat diet

11
Q

Is ideally suited as a receptor site for body adiposity as well as for integration of hormonal and neural signals because its “leaky BBB” and location at the base of the hypothalamus

A

Arcuate nucleus

12
Q

3% of subjects with severe early onset obesity have a __ mutation

A

Leptin receptor

13
Q

Breaks down GLP-1

A

DPP-4

14
Q

__ have been proven to have higher circulating leptin levels in proportion to fat mass when comparing them to their cohort

A

Females

15
Q

Released postprandially from I cells in the small intestine

Reduces food intake through CCK1 receptors on the vagus nerve

A

CCK

16
Q

For longer-term energy regulation, humoral signals derived from __ are integrated in specific regions of the hypothalamus

A

adipose tissue

17
Q

Refers to the energy expenditure associated with digestion, absorption, and increased sympathetic nervous system activity after eating a meal

5-10% of TEE

A

Thermic effect of feeding (TEF)

18
Q

Primary brain area regulating appetite and response to emotions

May mediate a hunger response even when an individual is not physically hunger

A

Amygdala

19
Q

Day-to-day intake is primarily governed by which hormone?

A

Ghrelin

20
Q

Leptin is a key regulator of signaling in the hypothalamic __ __

A

Arcuate nucleus (ARC)

21
Q

Only gut derived signal that increases hunger

A

Ghrelin

22
Q

Expressed in the CNS and in the distal ileum and colon
- rapidly released after food ingestion into the circulation in response to nutrient uptake

Incretin hormone - controls blood sugar by stimulating insulin secretion and inhibiting both glucagon secretion and gastric emptying

A

GLP-1

23
Q

2 neuropeptides that leptin acts to release from the arcuate nucleus
- anorexigenic

A

POMC (turns into alpha-MSH)

CART

24
Q

Mechanoreceptors and chemoreceptors in the GI tract signal through the __ to the brainstem for short-term regulation of appetite (hunger and satiety).

A

Vagal nerve

25
Q

Leptin system is more effective in signaling __ of energy stores and less effective in signaling energy surplus

A

Depletion

26
Q

Acts as an inverse agonist on constitutively active MC4 receptors

During a negative energy balance, __ neurons are activated and act to suppress the MC receptor activity

A

AgRP

27
Q

__ is associated with metabolic regulation in gut hormones that are intended to drive energy stores back to initial replete levels

A

Weight loss

28
Q

Obesity is associated with __

As BMI increases, leptin increases
- saturation occurs at a certain level

A

Leptin resistance

29
Q

The default in the brain is the __ system

- this is due to evolution’s priority on eating to stay alive

A

Orixogenic (hunger)

30
Q

Peptide hormone released from the fundic region of the stomach

Endogenous ligand for the growth hormone -secretagogue receptor (GHS-R)

Only known factor to increase appetite

Increased by fasting, fall after a meal

A

Ghrelin

31
Q

6% of children with severe obesity have a mutation in the __

A

MC4 receptor

32
Q

Lesions to the __ hypothalamus induce loss of appetite

A

Lateral

33
Q

__ administration has been shown to reduce food intake mediated through both peripheral and central mechanisms, via projection to the hypothalamus and brainstem areas

Mimetic agents are used as drugs for Type 2 diabetes and cause weight loss

A

GLP-1

34
Q

Has a reproductive function by letting the brain known that menstruation can begin because body fat starts to accumulate during pregnancy

A

Leptin

35
Q

Result of a volitional mechanical work

  • exercise
  • daily activities

Also, result of nonvolitional mechanical work

  • fidgeting
  • maintaining posture
  • spontaneous muscle contractions

15-30% of TEE

A

Physical activity

36
Q

Despite the elevated secretion and circulation of __ in obesity, CNS levels do not rise proportionately due to saturation of the leptin receptor and reduced intracellular signaling

Thus, the CNS does not properly sense the expanded adipose mass

A

Leptin

37
Q

Refers to the energy expended for normal cellular and organ function during post-absorptive resting conditions

Comprises 65% of TEE

Can be clinically measured by indirect calorimetry

A

RMR (Resting metabolic rate)

38
Q

Pathways consist of dopaminergic neurons which originate in the ventral tegmental area and substantia nigra in the midbrain and project throughout the brain

Responsible for “liking, wanting, and craving of food”
- responsible for food-seeking behavior

A

Hedonic System (reward center)

39
Q

Receptors that mediate the effects of __ belong to the NPY receptor family with high affinity for the NPY2R in the arcuate nucleus

A

PYY

40
Q

Adipose-derived satiety hormone
- secreted in diurnal rhythm

Receptor in the CNS is a member of the IL-6 receptor family of type I cytokine receptors

A

Leptin

41
Q

Comprised of 3 components:

  1. Resting metabolic rate (RMR)
  2. Thermic effect of feeding (REF)
  3. Energy expenditure of physical activity (PA)
A

Daily total energy expenditure (TEE)

42
Q

Neuroendocrine peptide that is co-secreted together w/ insulin from pancreatic islet beta-cells

Plasma levels increase in response to nutritional stimuli

Inhibits gastric emptying and glucagon secretion and reduces short-term food intake

Directly stimulates neurons in the area postrema of the hindbrain

Mimetic agents used as a DM medication and cause weight loss

A

Amylin

43
Q

Produced from the ob gene expressed in adipose cells

Communicates the status of energy stores to the brain

A

Leptin

44
Q

2 neuropeptides that leptin acts to inhibit in the arcuate nucleus
- orixogenic

A

AgRP and NPY

45
Q

Injury or lesions in the hypothalamus may result in a pattern of weight gain that is characterized as abrupt in onset and rapidly accelerating

Causes include:

  • craniopharyngioma
  • head trauma
  • sarcoidosis
  • aneurysm
  • meningioma
  • metastasis
  • surgery
  • radiation
A

Hypothalamic obesity