Obesity

Question 1

BMI is

Answer 1

Mass (kg) /height^2 (m)

Question 2

Things to consider with BMI

Answer 2

South Asian, Chinese, Middle Eastern,black African or African Caribbean populations
Measures overall weight, not fat
No detail on weight distribution

Question 3

BMI considered overweight

Answer 3

23-27-4

Question 4

BMI considered obese

Answer 4

27.5 +

Question 5

Health risks of obesity

Answer 5

CVD
Diabetes
Some cancers
Musculoskeletal diseases

Question 6

Obesity : ,about 80-85% of developing?

Answer 6

Type 2 diabetes

Question 7

Fundamental cause of weight gain is?

Answer 7

An energy imbalance between calories consumed and calories used up

Question 8

Factors contributing to obesity?

Answer 8

Societal
Biological
Economic
Psychological

Question 9

Complex factors regulating body weight

Answer 9

Body weight is very finely controlled
- homeostatic mechanism
Hypothalamic input
- people with injury to hypothalamus, more likely to put on weight
Neurohormonal integration

Question 10

Lepton is the product of?

Answer 10

The ob gene

Question 11

Where is Leptin synthesised?.

Answer 11

Adipocytes
- glucocorticoids, insulin and oestrogen increase
- B- adrenoceptor agonists reduce

Question 12

What effect does leptin administration have on body weight?

Answer 12

Decreases it

Question 13

CNS effect when hungry. Role of Leptin

Answer 13

Leptin decreases
Neuropeptide Y/ agouti- related protein neurons (NPY/AGRP) neurons are stimulated to release NPY or AGRP

Question 14

CNS effect when feeding. Role of Leptin

Answer 14

Lepton levels increase
Stimulates prepro-opiomelanocortin (POMC) neurons in the brain which release another hormone= alpha- melanocyte stimulating hormone (alpha-MSH)

Question 15

What is stimulated in the brain by hormones in response to hunger or feeding?

Answer 15

Neural pathways

Question 16

Where are NPY/AGRP neurones and POMC situated?

Answer 16

Within the arcuate nucleus within the hypothalamus

Question 17

Stimulation of POMC neurons by Leptin after feeding releases what hormones? Has what effects?

Answer 17

Release alpha MSH which act on various pathways to increase anorexic pathways

Lead to decrease in appetite and thus food intake, and increase energy expenditure

Question 18

Stimulation of NPY/AGRP neurons by Leptin after hunger releases what hormones? Has what effects?

Answer 18

Releases NPY /AGRP which stimulate appetite
Increases food intake and decrease energy expenditure

Question 19

Anorexia means

Answer 19

A decrease in appetite which is normal part of energy consumption and balance in the body, although used to describe a group of eating disorders characterised by low weight

Question 20

Ghrelin is produced by?

Answer 20

Cells in the GI tract

Question 21

Role of ghrelin when hungry

Answer 21

Levels are high, leptin =low
Inhibit its POMC neurons and stimulates the NPY/AGRP neurons to increase appetite and decrease energy expenditure

Question 22

When do ghrelin levels fall?

Answer 22

After eating as lepton levels rise

Question 23

Mutations in lepton pathways have been shown to underlie obesity.
List some Monogenetic causes of obesity linked to:

Answer 23

Leptin receptors
POMC neurons
Melanocortin receptors (MCR4) which are stimulated by (alpha- MSH)

Question 24

Circulating levels of Leptin are normally (increased/decreased) in obesity?

Answer 24

Increased

Question 25

Leptin in obesity happens how?

Answer 25

Via leptin resistance which is common in obesity, whereby it is produced but the body does not respond to it as effectively

Question 26

Other factors in obesity

Answer 26

Inflammation: adipocytes produce cytokines, increased levels of TNF-alpha, IL-6
Oxidative stress: reactive oxygen species (ROS)
Polygenetic: about 50 genes strongly associated with risk (40 -70%), combination of environmental factors and genetic susceptibility