Animal Nutrition

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appetite-regulating hormones

Leptin

PYY

Insulin

Ghrelin

Slide 73

Obese mouse with mutant ob gene (left) next to wild-type mouse.

EXPERIMENT

RESULTS

Slide 74

Obesity and Evolution

The problem of maintaining weight partly stems from our evolutionary past, when fat hoarding was a means of survival.

A species of birds called petrels become obese as chicks; in order to consume enough protein from high-fat food, chicks need to consume more calories than they burn.

Slide 75

A plump petrel chick

Slide 76

Fat cells from the abdomen of a human

100 µm

Slide 77

Review

Bloodstream

Veins to heart

Lymphatic system

Small intestine

Esophagus

Stomach

Lipids

Mouth

Hepatic portal vein

Absorbed food (except lipids)

Absorbed water

Secretions from the gastric glands of the stomach

Secretions from the pancreas and the liver

Liver

Rectum

Anus

Large intestine

Slide 78

You should now be able to:

Name the three nutritional needs that must be met by an animal’s diet.

Describe the four classes of essential nutrients.

Distinguish among undernourishment, overnourishment, and malnourishment.

Describe the four main stages of food processing.

Distinguish between a complete digestive tract and a gastrovascular cavity.

Slide 79

Follow a meal through the mammalian digestive system:

List important enzymes and describe their roles

Compare where and how the major types of macromolecules are digested and absorbed

Relate variations in dentition with different diets.

Explain where and in what form energy-rich molecules may be stored in the human body.