CHAPTER 51 – NUTRITION, DIGESTION, AND ABSORPTION
I. What Do Animals Require from Food?
a. humans must obtain essential fatty acids
i. linoleic acid is one that helps synthesize other unsaturated fatty acids
b. macronutrients: elements required in large amounts (e.g. calcium)
c. micronutrients: elements required in tiny amounts (e.g. iron)
d. vitamins: organic compounds that cannot be synthesized
i. species-specific
ii. water-soluble or fat-soluble
e. nutrient deficiency leads to malnutrition – chronic malnutrition leads to a
deficiency disease
i. scurvy – lack of vitamin C
ii. anemia – lack of iron
f. inability to absorb a nutrient can also lead to disease
i. pernicious anemia – vitamin B12 is not absorbed in stomach
II. How Do Animals Ingest and Digest Food?
a. how organisms acquire nutrition
i. saprobes: absorb nutrients from dead organic matter
ii. detritivores: actively feed on dead organic matter
iii. predators: feed on living organisms
1. herbivores: feed on plants
2. carnivores: feed on animals
3. omnivores: feed on both
4. filter feeders: filter small organisms from an aquatic environment
5. fluid feeders: include mosquitoes
b. herbivores
i. food is low in energy and hard to digest
ii. spend a long time feeding
iii. have specialized adaptations such as a trunk, a long neck, or teeth for
grinding
c. carnivores
i. have specialized adaptations for detecting, killing, and ingesting prey
1. bats – echolocation
2. snakes – fangs, hinged jaw
3. jellyfish – specialized cells called nematocysts inject toxins
d.
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, e. digestion usually begins in a body cavity
i. gastrovascular cavities connect to outside through a single opening
1. tubular guts have opening at each end
a. mouth takes in food
b. wastes are eliminated through anus
ii. food is broken up in the mouth cavity by teeth, radula (snails), or
mandibles (arthropods)
iii. birds grind food with small stones in their gizzards
iv. stomachs and crops are storage chambers
1. allow for gradual digestion
v.
f. small food particles delivered into intestines (with villi and microvilli)
i. nutrients absorbed in midgut
ii. hindgut recovers ions and water and stores undigested waste as feces
iii. muscular rectum expels feces
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I. What Do Animals Require from Food?
a. humans must obtain essential fatty acids
i. linoleic acid is one that helps synthesize other unsaturated fatty acids
b. macronutrients: elements required in large amounts (e.g. calcium)
c. micronutrients: elements required in tiny amounts (e.g. iron)
d. vitamins: organic compounds that cannot be synthesized
i. species-specific
ii. water-soluble or fat-soluble
e. nutrient deficiency leads to malnutrition – chronic malnutrition leads to a
deficiency disease
i. scurvy – lack of vitamin C
ii. anemia – lack of iron
f. inability to absorb a nutrient can also lead to disease
i. pernicious anemia – vitamin B12 is not absorbed in stomach
II. How Do Animals Ingest and Digest Food?
a. how organisms acquire nutrition
i. saprobes: absorb nutrients from dead organic matter
ii. detritivores: actively feed on dead organic matter
iii. predators: feed on living organisms
1. herbivores: feed on plants
2. carnivores: feed on animals
3. omnivores: feed on both
4. filter feeders: filter small organisms from an aquatic environment
5. fluid feeders: include mosquitoes
b. herbivores
i. food is low in energy and hard to digest
ii. spend a long time feeding
iii. have specialized adaptations such as a trunk, a long neck, or teeth for
grinding
c. carnivores
i. have specialized adaptations for detecting, killing, and ingesting prey
1. bats – echolocation
2. snakes – fangs, hinged jaw
3. jellyfish – specialized cells called nematocysts inject toxins
d.
This study source was downloaded by 100000837653068 from CourseHero.com on 01-21-2022 02:02:51 GMT -06:00
https://www.coursehero.com/file/34446701/Chapter-51docx/
, e. digestion usually begins in a body cavity
i. gastrovascular cavities connect to outside through a single opening
1. tubular guts have opening at each end
a. mouth takes in food
b. wastes are eliminated through anus
ii. food is broken up in the mouth cavity by teeth, radula (snails), or
mandibles (arthropods)
iii. birds grind food with small stones in their gizzards
iv. stomachs and crops are storage chambers
1. allow for gradual digestion
v.
f. small food particles delivered into intestines (with villi and microvilli)
i. nutrients absorbed in midgut
ii. hindgut recovers ions and water and stores undigested waste as feces
iii. muscular rectum expels feces
This study source was downloaded by 100000837653068 from CourseHero.com on 01-21-2022 02:02:51 GMT -06:00
https://www.coursehero.com/file/34446701/Chapter-51docx/
