Brainscape's Knowledge GenomeTM

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


See full index

GASTROENTEROLOGY phase 1b > 1b Appetite > Flashcards

1b Appetite Flashcards

1
Q

What are the three things which stimulate thirst?

A
  1. Body fluid osmolality
  2. Blood Volume lowers
  3. Blood Pressure lowers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which of the three stimuli for thirst is the most potent?

A

An INCREASE in plasma osmolality

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

Which hormone is the main regulator for osmolality?

A

ADH or Vasopressin

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

Where does ADH act?

A

Via the aquaporin 2 channel in the kidneys - renal collecting duct

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

Where is ADH stored

A

posterior pituitary gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

ADH is secreted through neurons in what region of the brain?

A

Hypothalamus

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

What regions are the sensory osmoreceptors found in the hypothalamus?

A

Organum vasculosum of the lamina terminalis (OVLT)

Subfornical Organ (SFO)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q
  • Describe the process that leads to ADH release initiated by osmoreceptors
A
  • When plasma is more concentrated, water moves out the osmoreceptors, causing them to SHRINK
  • This means the PROPORTION OF CATION channels in the membrane increases - membrane depolarises
  • Send signals to the ADH producing cells to increase ADH → Fluid retention, Invokes drinking
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

When is thirst completely satisfied?

A

Thirst is only completely satisfied once plasma osmolality is decreased or blood volume or arterial pressure corrected.

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

Which receptors are involved in the sensation of thirst?

A

Receptors in mouth, pharynx, oesophagus are involved - relief of thirst via these is short lived

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

How does the renin-angiotensin system REACT to a decrease in blood pressure?

A
  • Juxtaglomerular cells of renal afferent arteriole, once the decreased blood pressure here is detected, will release renin
  • cleaves angiotensinogen in the liver to release angiotensin I
  • Angiotensin I is converted into Angiotensin II in the lungs
  • Angiotenin II Binds to receptors on the intraglomerular messenger cells
  • This binding causes these cells to contract along with the blood vessels surrounding them, which then leads to release of aldosterone in the zona glomerulosa of the adrenal cortex

This increases blood pressure

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

What are the four functions of angiotensin II?

A

Induces thirst

ADH secretion as well

Vasoconstriction, increase in sympathetic activity

H2O retention via NaCl absorption and K+ excretion

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

What 2 types of drugs that affect the RAAS are known to treat high blood pressure?

A

ACEi
Direct Renin Inhibitors

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

How does weight homeostasis work in an overfed state? (Adipose tissue expansion)

A
  • Increased sympathetic activity
    -Increased energy expenditure
    -Decreased hunger and food intake
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does weight homeostasis work in underfed state? (Reduction in fat mass)

A

Increased hunger and food intake

Decreased energy expenditure

Decreased sympathetic nervous system activity

Decreased thyroid function

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

What system defends against reduction of body fat?

A

Central Circuit Defence

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

What system defends against rapid expansion?

A

Yet to be discovered

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

What is the significant hormone involved in the central circuit defense against reduction of body fat?

A

Leptin

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

Where does the most important regulation of appetite occur?

A

Hypothalamus

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

What are the two main gut hormones involved in the regulation of appetite?

A

GHRELIN, PYY & other gut hormones

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

Which nerve do signals from Ghrelin and PYY travel to the brainstem via?

A

Vagus nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Other than the gut hormones through vagus nerve, how else does the hypothalamus receive input about appetite regulation?

A

Neural input from the periphery and other brain regions

Leptin

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

What part of the hyopthalamus is the most important site in regulation of food intake? Describe it also.

A

Arcuate nucleus - An aggregation of neurones in the medial basal part of the hypothalamus

24
Q

What is the name of the nucleus in the hypothalamus that has neurons projecting to the posterior pituitary?

A

Paraventricular nucleus

25
Q

What is meant by orexigenic?

A

Appetite Stimulant

26
Q

What term is used to describe an appetite suppressor?

A

Anorectic

27
Q

how does the arcuate nucleus allow access to peripheral hormones?

A

Incomplete blood brain barrier

28
Q

Where are orexigenic peptides produced?

A

The lateral hypothalamus

29
Q

What is the ventromedial hypothalamus involved with?

A

Satiety - the feeling of being full

30
Q

where in the hypothalamus are melanocortins found??

A

Ventromedial hypothalaus

31
Q

Which neurones form part of the stimulatory system in the arcuate nucleus?

A

NPY/AGRP neuron

32
Q

Which neurones form part of the inhibitory system in the arcuate nucleus?

A

POMC neurone

33
Q

Which mutations cause morbid obesity in humans?

A

POMC deficiency and MC4-R mutations cause morbid obesity.

34
Q

What effect does the amygdala have on appetite?

A

Plays a strong role in the reward-motivation pathways in the brain

Regulating appetite with response to emotions

35
Q

How does the adipostat mechanism work?

A

Circulating hormones (can be leptin) are produced by adipose tissue

The more adipose tissue → the more hormones being produced

Hypothalamus senses the concentration of hormone

Hypothalamus uses this to alter neuropeptides to increase or decrease food intake

36
Q

What effect does leptin have on appetite?

A

Leptin decreases appetite

37
Q

What effect does leptin have on maintaining body temperature and therefore expenditure?

A

Leptin increases thermogenesis

This therefore increases energy expenditure

38
Q

Where is leptin produced?

A

adipocytes in white adipose tissue and enterocytes

39
Q

What are the level of leptin when the body fat is low and high?

A

Low when low, high when high

40
Q

What are the gastrointestinal hormones that regulate appetite released by?

A

Secreted by enteroendocrine cells in the stomach, pancreas & SB

41
Q

What are the two gut hormones which control appetite?

A

Ghrelin and PYY

42
Q

What is the overall function of ghrelin?

A

Stimulates appetite, increases gastric
emptying

43
Q

What are the functions of ghrelin in the gastrointestinal tract?

A

Increase gastric motility

Increase acid secretion

44
Q

how specifically does ghrelin affect appetite?

A

Directly modulates neurons in the arcuate nucleus to increase appetite

Stimulates NPY/Agrp neurons

Inhibits POMC neurons

45
Q

When are levels of ghrelin highest in the body?

A

Before a meal

46
Q

other than appetite what does ghrelin regulate?

A

Regulation of reward, taste sensation, memory, circadian rhythm

47
Q

What method is used to measure the levels of ghrelin throughout the day?

A

Radioimmunoassay

48
Q

What is the rhythm of ghrelin release?

A

Diurnal

Rising throughout the day to highest at 8am, 12pm and 4pm

Lowest at 9am

49
Q

What is PYY?

A

Peptide tyrosine tyrosine

50
Q

Where is PYY released?

A

Short peptide released in the terminal ileum (TI) and colon in response to feeding (36 Amino acids)

51
Q

what effect does PYY have on appetite?

A

Reduced appetite

52
Q

How does PYY reduce appetite?

A
  • Inhibits NPY release
  • Stimulates POMC neurons
53
Q

What types of foods initiates the best PYY response?

A

Dietary fibres, wholegrains, and enzymatic breakdown of crude fish proteins

54
Q

What are some of the side effects of PYY?

A

Nausea, fullness especially with higher dose

Less hunger and early fullness in the premeal period during PYY infusions

55
Q

What are some of the comorbidities with obesity?

A

Stroke
Depression
MI
Hypertension
Bowel Cancer
Gout
OA
Sleep Apnoea

56
Q

Other than bowel cancer, what other cancer is suspected of being related to obesity?

A

Breast

57
Q

What 2 categories of risk factors lead to an increase in obesity?

A

Genetic and environmental

GASTROENTEROLOGY phase 1b (12 decks)

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