BIOL 2112 Chapter Notes - Chapter 21: Chymotrypsin, Peristalsis, Chyme
4 Jun 2018
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1.Define and distinguish between carnivores, herbivores, omnivores, filter feeders,
substrate feeders, fluid feeders, and bulk feeders.
Herbivores- eat plants
Carnivores- eats animals
Omnivores- eat both plants and animals
Filter Feeders- sift small organisms or food particles from water
Substrate Feeders-live in or on their food source and eat their way through it
Bulk feeders- ingest large pieces of food
2.Describe the four stages of food processing.
1. Ingestion- the act of eating
2. Digestion- the breaking down of food into molecules small enough for the body to
absorb.
3. Absorption- the take-up of the products of digestion, usually by the cells lining the
digestive tract
4. Elimination- the removal of undigested materials from the digestive tract
3.Compare the structures and functions of a gastrovascular cavity and an alimentary canal.
Grastrovascular cavity- has a single opening (mouth)
Theses are Cnidarians and Flatworms
Food enters the mouth
Enzymes from the cells lining the gastrovascular cavity break down the food.
Other cells engulf these small food particles
Undigested materials are expelled back out the mouth
Alimentary canal- Has mouth at one end and anus at the other (2 openings)
Has a one way flow of food
Food passes through Pharynx or throat.
-Esophagus may channel food to crop, gizzard, or stomach. (Crop is a pouch like organ in which
food is softened and stored) (Stomachs and gizzards may also store food temporarily, much more
muscular and they churn and grind food)
-Chemical digestion and nutrient absorption occur in intestine
-Undigested materials expelled through anus
4.Describe the specialized digestive systems of an earthworm, a grasshopper, and a bird.
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They use a one-way flow
Pharynx -> esophagus -> crop -> gizzard -> stomach -> intestines -> anus
Earthworm
-Muscular pharynx that sucks food in through the mouth
-Food passes through the esophagus and is stored in the crop
-Mechanical digestion in muscular gizzard (pulverizes food with aid of bits of sand and
gravel)
-Chemical digestion and absorption occur in the intestine
-Undigested material is expelled through the anus
Grasshopper
-Crop where food is stored
-Most digestion occurs in the midgut region (projections called gastric pouches function
in digestion and absorption)
-Hindgut mainly reabsorbs water and compacts waste
Bird
-3 separate chambers: crop, stomach, and a gravel filled gizzard, in which food is
pulverized.
-Chemical digestion and absorption occur in the intestine
5.Describe the main components of the human alimentary canal and the associated
digestive glands.
Food is ingested and chewed in the mouth -> tongue pushes it to pharynx -> peristalsis
keeps it moving -> moves into and out of stomach by sphincters -> absorption in the small
intestines -> undigested material moves through large intestine and then goes out the anus
6.Describe the functional components of saliva and the types and functions of the teeth in
humans.
Salivary glands release a slippery glycoprotein that moistens and lubricates food for
easier swallowing, which then buffers that neutralize acids. Then the salivary enzyme amylase
that begins the hydrolysis of starch and then antibacterial agents that kill some bacteria ingested
with food.
Teeth are designed to break down food so it is easier to digest.
7.Explain how swallowing occurs and how food is directed away from the trachea.
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find more resources at oneclass.com
Document Summary
1. define and distinguish between carnivores, herbivores, omnivores, filter feeders, substrate feeders, fluid feeders, and bulk feeders. Filter feeders- sift small organisms or food particles from water. Substrate feeders-live in or on their food source and eat their way through it. 3. compare the structures and functions of a gastrovascular cavity and an alimentary canal. Enzymes from the cells lining the gastrovascular cavity break down the food. Undigested materials are expelled back out the mouth. Alimentary canal- has mouth at one end and anus at the other (2 openings) Esophagus may channel food to crop, gizzard, or stomach. (crop is a pouch like organ in which food is softened and stored) (stomachs and gizzards may also store food temporarily, much more muscular and they churn and grind food) Chemical digestion and nutrient absorption occur in intestine. 4. describe the specialized digestive systems of an earthworm, a grasshopper, and a bird. Pharynx -> esophagus -> crop -> gizzard -> stomach -> intestines -> anus.
