Brainscape's Knowledge GenomeTM

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


See full index

m2 > appetite regulation > Flashcards

appetite regulation Flashcards

1
Q

what is an orexigen?

A

A substance (hormone or drug) that increases food intake - appetite stimulant

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

when is an orexigen undesirable?

A

when its an unwanted side effect of medication (increases weight gain)

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

when can an orexigen be useful?

A

in cachexia treatment or AIDS/cancer

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

what is an anorexigen?

A

Substance (hormone or drug) that inhibits food intake

Activates specific neuronal pathways to alter eating behaviour

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

in what ways can food be broken down in the GI tract?

A 
o	Mastication (chewing) in the oral cavity along with breakdown via amylase production in the mouth
o	Stomach acid breaks down food
o	Proteases
o	Mechanical movements e.g. rhythmic gastric contractions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

how is food broken down in the duodenum?

A

bile acids

pancreatic enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

where are most nutrients taken up?

A

small intestine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is GPR120 and what is its relevance?

A

medium to long chain FA receptor. People without this receptor have a tendency to gain weight –> obese phenotype

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what do enteroendocrine cells do and how?

A

sense the luminal environment

have GPCRs on the EEC surface which is how food intake is relayed to the rest of the body

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

name adaptations of the EECs and how are these useful?

A

long processes - can reach out through the lumen
triangular shape with a wider base - wide base has more secretory granules that contain hormones and peptides that regulate food intake

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what parts of the GI tract does the vagus nerve innervate?

A

stomach
small intestine
proximal colon

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

what activates chemoreceptors on the vagus nerve?

A

activated by mediators released by EEC cells

Respond to nutrients, hormones, pH, osmolality

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what activates mechanoreceptors on the vagus nerve?

A

o Gastric distension causes satiety

o Meal size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what controls the short term homeostatic control of appetite?

A

vagus nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what controls the long term control of appetite?

A

hypothalamus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what type of hormone is leptin?

A

adipokine - hormone made by adipose tissue

anorexigenic hormone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what does leptin do?

A

Satiety signal that affects all organs in the body but acts specifically in the hypothalamus
o Inhibits NPY/AgRP neurones
o Activates POMC/CART neurones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what do leptin levels correlate with?

A

body fat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what are leptin levels in obese people and why?

A

obese people have high leptin levels bc they have leptin resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

where is CCK synthesised?

A

I cells of the duodenum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is CCK released in response to and what does it do?

A
  • Released in response to fat and protein
  • Slows gastric emptying, releases bile and pancreatic enzymes
  • Activates vagus nerve  activates feeling of satiety
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what is PYY3-36?

A

Anorexigenic hormone released from L cells in the GI tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is PYY3-36 released in response to and what does it do?

A
  • Released in response to high fat/protein
  • Infusions lead to enhanced satiety
  • Directly inhibits NPY neurones and activates POMC neurones
  • Decreased food intake
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

when are PYY3-36 levels elevated?

A

• Elevated during bariatric surgeries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what receptor does PYY3-36 act on and where is it expressed?

A

• Y2 - primary receptor expressed in the periphery that regulates the vagal mechanisms of appetite reduction

26
Q

what can high concentrations of PYY3-36 cause?

A

nausea

27
Q

why isnt PYY3-36 used as a treatment for obesity?

A

narrow therapeutic range

28
Q

when is insulin released?

A
  • released in response to high glucose levels

- released following meals

29
Q

how does insulin act as a satiety signal?

A

o Inhibits NPY/AgRP neurones

o Activates αMSH/CART

30
Q

what hormone is GLP-1 similar to?

A

PYY

31
Q

where is GLP-1 released from?

A

L cells

32
Q

what does GLP-1 do?

A

o Decrease blood glucose

o Decreases food intake

33
Q

what are GLP-1 levels in obese subjects?

A

low

34
Q

why arent Exenatide/Liraglutide prescribed for weight loss?

A

bc of issues with pancreatitis

35
Q

what is pancreatic polypeptide released in response to? what does it do?

A
  • Released in response to food intake, proportional to calories
  • Decreases appetite
36
Q

what is oxontymodulin?

A

• Anorectic peptide product of preproglucagon

37
Q

what does oxontymodulin do?

A
  • Decreases ghrelin levels in plasma
  • May also increase energy expenditure
  • Effective weight loss
38
Q

what is ghrelin?

A

the major peripheral orexigenic hormone (hunger hormone)

39
Q

where is ghrelin made?

A

the stomach

40
Q

what inhibits ghrelin?

A

food intake - suppressed in proportion to the calories ingested

41
Q

what are the effects of ghrelin?

A

glucose homeostasis, gut motility, pancreas function, inflammation etc

42
Q

what does ghrelin act on?

A

• Acts directly on the hypothalamus via the vagus

o Receptors are present in the brainstem and the mesolimbic dopaminergic system

43
Q

what are the short and long term actions of ghrelin?

A

o Meal initiator, contributes to hunger
o Chronic administration leads to hyperphagia
o Malignant ghrelinoma, preserved obesity

44
Q

what are ghrelin levels in obese patients?

A

low

45
Q

what is the diversity of the microbiome in obese people like?

A

reduced diversity

46
Q

where is the hypothalamus found?

A

below the thalamus

47
Q

what are the 2 mechanisms of the neuroendocrine function of the hypothalamus?

A

o Direct neuronal connection to anterior pituitary

o Hypophyseal portal system

48
Q

what does the hypothalamus regulate?

A

regulates metabolic rate by influencing pituitary function, feeding, stress response, water balance, sleep-wake cycle, thermoregulation etc

49
Q

what hypothalamic nucleus controls food intake?

A

arcuate nucleus

50
Q

what is another name for the arcuate nucleus?

A

the lateral part of the ventromedial nucleus of the hypothalamus

51
Q

what are the 2 main groups of neuroendocrine neurons?

A

Orexigens: Neuropeptide Y (NPY) and Agouti related peptide (AgRP)

Anorexigens: Cocaine and Amphetamine related transcript (CART) and pro-opiomelanocortin (POMC)

52
Q

describe the central orexigenic pathway

A

• AGRP/NPY neurones in arcuate nucleus of hypothalamus
• Activated by ghrelin
• Inhibited by insulin and leptin
• Releases NPY which activates Y1 receptors
o Increase food intake by activating second order neurones
o Inhibits POMC/CART neurones
• AgRP is a melanocortin receptor antagonist

53
Q

what do POMC-deficient humans develop?

A

hyperphagia and obesity

54
Q

describe the central anorexigenic pathway?

A
  • POMC/CART neurones in arcuate nucleus of hypothalamus
  • Activated by insulin and leptin
  • Decrease food intake by releasing melanocortins
55
Q

what is the main melanocortin secreted in the central anorexigenic pathway? what does it do?

A

• Main is α-melanocortin-stimulating hormone (α-MSH)
o activating second order neurones (MCR4 receptors)
o Inhibits NYY/AgRP neurones (MCR3 receptors)

56
Q

what effect does increased and decreased malonyl-CoA have on food intake?

A

o Increased malonyl-coA supresses food intake

o Decreased malonyl coA increases food intake

57
Q

is serotonin and anorexigen or orexigen?

A

anorexigen

58
Q

what effect do serotonin levels have on weight gain and how?

A

Inhibits food intake – its depletion promotes weight gain

59
Q

what neurones does serotonin act on in appetite regulation and what effect does it have on each?

A

o They increase signalling (simulate) activity in the POMC neurones (via the 5HT2CR)
o They decrease signalling in the AgRP neurones (via the 5HT1BR)

60
Q

what is Lorcaserin?

A

5HT2c receptor agonist - Moderately effective as weight loss treatment

m2 (24 decks)

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