regulation of energy balance

Question 1

which GI diseases can cause spontaneous weight loss

Answer 1

• chronic pancreatitis - CF - IBD - parasitic infection

Question 1

what other than gene mutations can lead to obesity

Answer 1

epigenetics - early exposure to high energy diet –> epigenetic changes in genes controlling hunger

Question 2

what is the association between food and energy expenditure

Answer 2

in a normal person - people will increase E expenditure in an effort to prevent weight gain and vice versa

Question 2

how is leptin transported into the brain

Answer 2

by a receptor on the choroid plexus

Question 4

how the double labeled water method of measuring energy expenditure work

Answer 4

label the body water with stable isotopes of oxygen and hydrogen. - O2-18 is lost from the body in the form of water and CO2 - 2H is lost only as water - difference between them reflects the CO2 production (result of fat, carbohydrate and protein oxidation)

Question 5

what determines how much leptin is made

Answer 5

the size of the adipocytes - bigger cell - more leptin

Question 6

what is the split up of energy expenditure by the body?

Answer 6

• most basal (65-75%)
• Thermogenesis (15-20%)
• activity (10-15%)

Question 7

primary NTs produced in the arcuate nucleus for hunger/satiety and what does each one specifically do?

Answer 7

NPY - cause you to eat AGRP - cause you to eat CART - inhibits food intake alpha-MSH - inhibits food intake

Question 8

if you lack orrexin gene what happens

Answer 8

narcolepsy

Question 8

what is the most common association of leptin and obesity

Answer 8

most people who are obese are resistant to leptin signals due to a SNP in the receptor

Question 9

why does glucose and other nutrients inhibit hunger

Answer 9

• increases LCFA-CoA which inhibits food intake

Question 10

which main infections can cause spontaneous weight loss

Answer 10

• TB - subacute bacterial endocarditis - amoebic abscess - HIV

Question 10

which malignancies commonly cause spontaneous weight loss

Answer 10

• bowel - pancreas - liver - lymphoma - leukaemia

Question 11

if all things equal…. if the amount of leptin increases.. what happens to hunger

Answer 11

reduces

Question 13

what are the NTs produced in the paraventricular nucleus for hunger/satiety and what are their functions?

Answer 13

oxytocin CRH both stimulate food intake

Question 15

which areas of the hypothalamus interact

Answer 15

arcuate nucleus Paraventricular hypothalamic nucleus laternal hypothalamus

Question 16

what peripheral signals does the hunger centre of the brain respond to?

Answer 16

size of fat stores presence of food int he gut

Question 16

why does a diabetic not respond to leptin injection to stop eating

Answer 16

has a mutation in the R for leptin

Question 17

what causes obesity

Answer 17

energy in>energy out - only in the weight gain phase

Question 19

why do some people put on weight when over fed and others dont?

Answer 19

due to change in energy expenditure - those who put on weight didnt change their activity thermogenesis - those who didnt put on weight have a big change in activity thermogenesis (fidgiting)

Question 19

where is leptin synthesised

Answer 19

adipocytes

Question 21

function of leptin

Answer 21

signals the size of the fat stores in the body

Question 22

common mutations causing human obesity

Answer 22

• leptin gene - leptin gene R - MSH gene signalling

Question 23

what is the name of the equations used to predict energy expenditure

Answer 23

Harris-Benedit equations

Question 24

which endocrine disease can casue spontaneous weight loss

Answer 24

• untreated T1DM - Throtoxicosis - Addison’s disease (lack cortisol)

Question 26

genetic inheritance of leptin gene mutation

Answer 26

homozygous

Question 27

2 functions of orrexin

Answer 27

• inhibits food intake - stabilises the arousal system for sleep - wakefullness

Question 28

which part of the brain controls the set point for weight control

Answer 28

the hypothalamus

Question 29

what are some methods of measuring energy expenditure

Answer 29

• whole room respiratory chambers - metabolic carts (hood) - double labeled water

Question 30

medical complications of anorexia nervosa

Answer 30

• amenorrhoea - lanugo hair - bradycardia - anaemia

Question 31

what are the names of the neurons that produce the NTs in the arcuate nucleus of the hypothalamus involved in hunger/satiety

Answer 31

primary neurons - NPY and AGRP PomC neurons - CART and alpha-MSH

Question 32

approximating energy expenditure is based on what 4 things

Answer 32

• sex - height - weight - age - activity

Question 33

what NTs can modulate the basic pathways in the hypothalamus involved in hunger/satiety?

Answer 33

opoids dopamine endocannabinoids