Bio Ch. 43 Digestive System

Front 1

disgestion

Back 1

the process that physically and chemically breaks down food

Front 2

digestive systems

Back 2

-take in food and break complex molecules into simpler forms that can be absorbed
-material that cannot be absorbed is expelled

Front 3

ruminant animals

Back 3

-herbivores that are able to break down cellulose and extract nutrients from tough plant matter
-Have elaborate digestive systems that house microorganisms which break down cellulose (using cellulase enzymes)

Front 4

rumination

Back 4

regurgitate and rechew food (cud)

Front 5

intestinal length is...

Back 5

-correlated with diet
-because cell walls are difficult to digest, herbivore intestines are long to allow more time for nutrient absorption
-carnivore intestines are relatively short because proteins are easy to digest

Front 6

incisors used for

Back 6

biting

Front 7

canines used for

Back 7

tearing

Front 8

premolars used for

Back 8

grinding

Front 9

molars used for

Back 9

crushing and chewing

Front 10

crop

Back 10

stores and moistens food

Front 11

stomach

Back 11

secretes enzymes

Front 12

gizzard

Back 12

muscular with a hard lining for grinding food (birds)

Front 13

small intestine

Back 13

further digestion and absorption

Front 14

functions of saliva

Back 14

-contains amylase: breaks down starches into sugars
-contains bacteria-killing enzymes and antibodies
-lubricates food: helps with swallowing
-carries food molecules to taste buds on tongue for food quality identification

Front 15

stomach

Back 15

disrupts food, begins protein digestion

Front 16

small intestine

Back 16

most digestion and absorption occurs here

Front 17

rectum

Back 17

stores feces

Front 18

salivary glands

Back 18

secrete lubricating fluid and starch-digesting enzymes

Front 19

pharynx

Back 19

shared digestive and respiratory passage

Front 20

epiglottis

Back 20

directs food down the esophagus

Front 21

esophagus

Back 21

transports food to the stomache

Front 22

gallbladder

Back 22

concentrates, stores bile from liver

Front 23

pancreas

Back 23

secretes buffers, several digestive enzymes (also an endocrine organ)

Front 24

large intestine

Back 24

absorbs water, houses bacteria, produces feces

Front 25

appendix

Back 25

no human function

Front 26

oral cavity, tongue, teeth

Back 26

grind food, mix with saliva

Front 27

esophagus

Back 27

-Swallowing forces food into a muscular tube called the esophagus
-The esophagus forms waves of muscular contraction (peristalsis) that carry food to the stomach

Front 28

stomach

Back 28

-is an expandable muscular sac
-connects to the small intestine, but the pyloric sphincter muscle keeps food from entering it

Front 29

3 major functions of the stomach

Back 29

-food storage and gradual release into the small intestine
-mechanical food breakdown by using churning contractions
-chemical food breakdown by stomach gland secretions

Front 30

food in the stomach is gradually turned into

Back 30

chyme (a mixture of partially digested food and stomach secretions)

Front 31

peristaltic waves

Back 31

propel food toward small intestine

Front 32

pyloric sphincter

Back 32

opens and lets chyme enter small intestine in small amounts

Front 33

small intestine

Back 33

-Most digestion occurs in the small intestine
-The small intestine is a narrow tube about 10 feet long
-Most absorption occurs in the small intestine
-The small intestine is well adapted for absorption of nutrients
-Has numerous folds with fingerlike projections (villi) on its surface to increase absorptive surface area
-Each villus cell has many microvilli that increase surface area even more

Front 34

Food is digested and absorbed with the aid of digestive secretions from three sources:

Back 34

-liver
-pancreas
-cells of the small intestine

Front 35

2 parts of large intestine:

Back 35

-Colon: most of its length
-Rectum: the terminal compartment

Front 36

large intestine

Back 36

-about 5 feet long and three inches wide
-a mix of water, undigested nutrients, and fiber enters the large intestine
-the large intestine contains bacteria that consume unabsorbed nutrients and synthesize vitamins
-the large intestine absorbs vitamins, leftover water, and salts

Front 37

digestion is controlled by

Back 37

-the nervous system and hormones
-Nervous control of digestion
Nervous system responds to sensory input, such as sight, smell, and taste