chapter 34: nutrition and digestive system

Bulk feeders

eating a large amount of food and digesting it slowly throughout the course of the day

What kind of feeders are humans?

bulk feeders

How do teeth depend on what kind of food the organism eats?

Herbivores, carnivores, and omnivores have adapted teeth to what kind of food they eat

incomplete digestive system

- contains a single opening
- food and waste enter and exit the same opening

What is the single opening of the incomplete digestive system called?

gastrovascular cavity

complete digestive system

- organism has two openings
- food enters the mouth, and waste exits through the anus

What is the name that forms the complete digestive system?

Alimentary canal

monogastric digestive system

Having a single chambered stomach (humans)

Avian digestive system

- having two stomachs (birds)

Proventriculus

- avian digestive
- contains digestive juices and enzymes

Gizzard

- avian digestive system
- grinds the hard things birds eat

Cloaca

Same hole in birds where feces and reproductive matter come out

Ruminant digestive system

- animals like cows and goats have 4 stomachs
- helps to process all the cellulose they digest

Rumen and reticulum

- contains bacteria and protist to digest cellulose → thus forming "cud"
- bacteria holds symbiotic relationship with organism

Omasum

cud is regurgitated, and re-eaten into this chamber

Abomasum

also known as the "true stomach"; enzymes are produced by ruminant digests the cud

What produces methane?

Bacteria

Is the human digestive system complete or incomplete?

Complete

Digestion is ...

Extracellular

What is the role of teeth?

mechanical digestion

Salivary glands

- enzymatic (chemical) digestion
- produces and secretes saliva which contains enzyme amylase which helps break down starches
- provides moisture to food

Tongue

mixes food and forms it into a bolus to swallow easily

Pharynx

also known as the "true stomach"; enzymes are produced by ruminant digests the cud

Epiglottis

flap that covers the opening into trachea and keeps food from coming into the air passages

Esophagus

- muscular tube that connects mouth to the stomach
- takes food to the stomach through peristalsis

Peristalsis

Rhythmic contraction of the smooth muscle to move food into further organs

The stomach contains deep folds that disappear as the stomach expands. What is it called?

Rugae

Epithelial linings has millions of ...

gastric pits

The stomach churns its contents and eventually produces what?

chyme

What creates a protective mucous layer in the stomach lining

epithelial cells

What bacterial infection is the cause of stomach ulcers

H. pylori

The small intestine has three main sections called....

the duodenum, jejunum, and ilium

Duodenum

where the bile duct and the pancreatic duct products enter the small intestine

Jejunum

where the majority of materials are digested and absorbed

Ilium

Reabsorption of the bile salt, waters, and additional vitamins

Exocrine gland

- produces pancreatic digestive juices and digestive enzymes into the duodenum

Pancreatic amylase

digests starch into maltose

Trypsin (from trypsinogen)

digests protein into peptides

Lipase

digests fat droplets to glycerol and fatty acids

What does the epithelial cells in the pancreas also produce?

enzymes

Bile

- produced in the liver, and stored in the gallbladder

What is the function of bile?

emulsifies fat and breaks compounds down

Gallstones

hardened deposits of bile in the gallbladder

Emulsification

the breaking down of a fat globule through bile salt

Cecum

has a small projection called the appendix (vestigial remnant)

Colon

- consists of 4 subdivisions that make up most of the large intestine
- ascending
- transverse
- descending
- sigmoid

What is the overall function of the large intestine?

Absorb water, salts, and some vitamins

Even though the large intestine is shorter than that small intestine in length it is still...

larger in diameter

Carbs are broken down into sugars by what?

Enzymes

Where is glucose absorbed?

small intestine

Vitamins

needed for metabolism and cannot be synthesized (excluding vitamin d)

Minerals

must be obtained from food