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Animal Nutrition II (Ch. 41). Roles of mouth, stomach, sm.&lg. Intestine in digestion Pepsin, pepsinogen Villi, microvilli Cecum Cellulose Cellulase. Keywords. Stomach. Digestive mechanisms in stomach. Mechanical Chemical enzymatic. Mechanical. Mixing and churning. Chemical.
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Roles of mouth, stomach, sm.&lg. Intestine in digestion Pepsin, pepsinogen Villi, microvilli Cecum Cellulose Cellulase Keywords
Digestive mechanisms in stomach • Mechanical • Chemical • enzymatic
Mechanical • Mixing and churning
Chemical • pH around 2 • Also breaks food down
Enzymatic • Pepsin • Breaks down proteins
Small intestine • Most of the enzymatic digestion occurs here
Most nutrient absorption takes place in small intestine • Structure: another example of increasing surface area
Large intestine (colon) • Major function is to reabsorb water
What would happen if you had a defect in pepsin production? • A. carbohydrate would not be digested well • B. meat would not be digested at all • C. perhaps decreased absorption of protein
What would happen if you had a defect in salivary amylase production?
What would happen if you had a defect in salivary amylase production? • A. You would die • B. You would be unable to digest starch • C. The pH of the stomach would be affected • D. None of the above
Which of the following would you least like to donate to science while you are still alive? • A. Cecum • B. Pancreas • C. Reproductive organs
What would happen if you had a defect in small intestine enteropeptidase?
Variations of vertebrate digestive system • Herbivorous mammals • Specialized fermentation chambers
Why does herbivory require specializations? • Plant tissue • Harder to break up • Contains cellulose • Nutrients less concentrated than meat
Only bacteria and protozoa can break down cellulose Via the enzyme cellulase
Cecum • Pouch at junction between lg and sm intestine • Large cecum in rabbits, some rodents, koala, horses • Full of symbiotic bacteria
Symbiosis • “living together”
Cecum function • Fermentation chamber • Bacteria breakdown cellulose • Feces must be reingested