2: Physiology of feeding and satiety Flashcards Preview

Gastrointestinal Week 1 2016/17 > 2: Physiology of feeding and satiety > Flashcards

Flashcards in 2: Physiology of feeding and satiety Deck (38)
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1
Q

What is energy homeostasis?

A

Energy intake is matched to energy expenditure

2
Q

How is excess energy stored?

A

Glycogen

Fat

3
Q

What is the result of accessible junk food plus a sedentary lifestyle

i.e intake / expenditure mismatch?

A

Obesity

4
Q

How is BMI calculated?

A

Weight (kg) / [Height (m)]2

5
Q

Which BMI ranges correspond to the classifications:

Underweight

Normal

Overweight

Obese

Morbidly obese

A

< 18.0Underweight

18.0 - 24.9Normal

25.0 - 29.9Overweight

30.0 - 39.9Obese

> 40.0Morbidly obese

6
Q

Levels of ___ have increased dramatically in the past 20 years.

A

obesity

7
Q

Obesity increases your chances of early ___.

A

death

8
Q

What are the two major factors influencing obesity?

A

Genetics - increases risk but not essential for disease expression

Environment - pushes people on to develop obesity

9
Q

What is an endocrine condition associated with obesity?

A

Type 2 diabetes mellitus

10
Q

What are some cardiovascular conditions associated with obesity?

A

Hypertension

MI

Stroke

11
Q

During which situation is the energy stored by fat used?

A

Starvation

Infection (where you don’t feel like eating)

12
Q

Increased body fat alters ___ function.

A

brain

13
Q

Where is information regarding energy intake integrated?

A

Hypothalamus

14
Q

What is satiation?

A

The feeling of “fullness” after a meal

15
Q

What is satiety?

A

The period of time between one meal and the next

16
Q

What are satiation signals?

A

Signals which control the feeling of “fullness”, i.e how much of a meal it feels right to eat

17
Q

See binder for details on satiation signals.

A
18
Q

Name a signal molecule which is released in response to fasting and hypoglycaemia?

A

Ghrelin

19
Q

What is ghrelin?

What conditions is it released in response to?

A

Hunger signal

Released in response to fasting and hypoglycaemia

20
Q

Ghrelin increases the magnitude of fat ___.

A

storage

21
Q

Which type of feedback mechanism controls body weight and energy stores?

A

Negative feedback

22
Q

Where is information re: body weight and energy storage integrated?

A

Hypothalamus

23
Q

What are adiposity signals?

A

Hormones which report the fat status of the body to the hypothalamus

24
Q

The levels of which two hormones increase as more fat is stored?

A

Leptin

Insulin

25
Q

What do leptin and insulin instruct the brain to do?

A

Eat less

Increase energy expenditure

26
Q

Patients with low leptin levels will have ___ appetites.

Why?

A

unrestrained - insatiable

Body thinks it is going through starvation as leptin reports level of energy storage

27
Q

What hormone, other than leptin, acts as an adiposity signal?

A

Insulin

28
Q

Which hormone is linked to food reward - the pleasure derived from eating?

A

Dopamine

29
Q

People with high fat content will have high levels of circulating ___.

A

leptin

30
Q

High circulating leptin levels associated with obesity cause receptors to become ___ to it.

A

insensitive

31
Q

What is the only drug currently used in the treatment of obesity?

A

Orlistat (Alli)

32
Q

How does orlistat reduce obesity?

A

Reduces fat absorption in the small intestine

33
Q

What are the major side effects of orlistat (Alli)?

A

Cramps

Severe diarrhoea (+/- steatorrhoea)

34
Q

What is bariatric surgery?

A

Surgery which aims to reduce the size of the stomach and therefore combat obesity

35
Q

Name an example of bariatric surgery.

A

Gastric band

Gastric bypass

36
Q

What effect does gastric bypass have on the excretion of satiation signals?

A

Reduced secretion of satiation signals

As there’s less stomach to do so

37
Q

Which drug uncouples the proton gradient to cause weight loss by overheating?

A

2,4-dinitrophenol (DNP)

38
Q

What is a major side effect of DNP?

A

Death by overheating