21.On which organ or tissue does leptin primarily act?

a.pancreas

b.intestines

c.adipocytes

d.hypothalamus

22.Which of the following is known to cause a reduction in fat cell number in mice?

a.injection of leptin

b.supplements of ghrelin

c.long-term resistance exercise

d.consumption of high-protein diets

23.Why is a leptin-deficient mouse much larger than its leptin-sufficient counterpart?

a.Leptin deficiency causes lower levels of ghrelin.

b.Leptin deficiency enhances appetite and decreases energy expenditure.

c.Leptin deficiency causes psychological depression, which leads to increased food intake.

d.Leptin deficiency reduces the desire to do physical activity, resulting in more excess energy available for fat storage.

24.Which of the following describes a relationship between leptin and energy balance?

a.Fat cell sensitivity to leptin is higher in obese people.

b.A deficiency of leptin is characteristic of all obese people.

c.Blood levels of leptin usually correlate directly with body fat.

d.Major functions of leptin include an increase in hunger and a decrease in metabolic rate.

25.From which of the following body parts is leptin secreted?

a.stomach

b.adipose tissue

c.small intestine

d.bone marrow

26.Which of the following is a function of ghrelin?

a.inhibits inflammation

b.stimulates appetite and energy storage.

c.stimulates growth of new blood cells

d.protects against insulin resistance

27.Which of the following proteins protects against type 2 diabetes?

a.PYY

b.leptin

c.ghrelin

d.adiponectin

28.Which of these is the observed effect of sleep deprivation on leptin and ghrelin?

a.Leptin and ghrelin both increase.

b.Leptin and ghrelin both decrease.

c.Leptin decreases while ghrelin increases.

d.Leptin increases while ghrelin decreases.

29.Why is weight loss, in part, more successful with exercise and also after bypass surgery?

a.Ghrelin levels are relatively low.

b.Adiponectin levels are relatively high.

c.PYY release from the hypothalamus is suppressed.

d.Leptin release from subcutaneous fat stores is enhanced.

30.Which of the following proteins decreases after a meal?

a.oxyntomodulin

b.pancreatic peptide

c.PYY

d.ghrelin