chapter 34: digestive systems and nutrition

Question 1

What does a digestive tract do?

Answer 1

-Contributes to homeostasis by providing nutrients needed to sustain life of cells
-Majority of animals have digestive tract

Question 2

What is an incomplete digestive tract? Example?

Answer 2

-digestive tract that has a single opening
-one opening for intake of food and elimination of waste
-Example: Planarian

Question 3

What is a complete digestive tract? Example?

Answer 3

-digestive tract that has both mouth & anus
-different openings for intake of food and elimination of waste
-Example: Earthworm

Question 4

What are continuous filter feeders? Examples?

Answer 4

-Acquire nutrients by continuing passing water through apparatus that captures food
-Examples: Clams, baleen whales, & oysters

Question 5

What are discontinuous filter feeders? Examples?

Answer 5

-Evolved ability to store food temporarily while its being digested
-developed Crop or stomach
-allows freed up activity time, less time spent on eating
-Examples: Squids, crickets, birds, lizards

Question 6

Characteristics of herbivores

Answer 6

• eat plants
  -Incisors for clipping plants
  -Premolars & molars for grinding plants
  -Ruminants (cattle, goats, and sheep) have a four-chambered stomach

Question 7

characteristics of carnivores

Answer 7

-Eat only other animals
-Dentition suitable for killing large animals or grasping small ones
-Meat rich in protein & easier to digest
-Shorter intestines

Question 8

characteristics of omnivores

Answer 8

-eat plants & animals
-Variety of specializations to accommodate both vegetation & meat
-Dentition specialized to accommodate vegetable & meat diet

Question 9

What kind of digestive system do humans have?

Answer 9

complete digestive tract

Question 10

what are the major structures in the digestive system?

Answer 10

mouth
pharynx and esophagus
stomach
small intestine
large intestine

Question 11

what are the accessory organs in the digestive system?

Answer 11

salivary glands
liver
gallbladder
pancreas

Question 12

the human digestive system is extracellular, which means:

Answer 12

performed outside individual cells; accumulation of them

Question 13

what is mechanical digestion?

Answer 13

physical breakdown of food itself

Question 14

what is chemical digestion

Answer 14

production of enzymes that change the chemical properties of food that we intake to break down

Question 15

characteristics of the mouth

Answer 15

-mechanical and chemical digestion
-salivary glands
-tongue

Question 16

characteristics of salivary glands

Answer 16

Three pairs that open by ducts
Enzyme to begin the digestion of starch
Saliva aids in mechanical process

Question 17

characteristics of tongue

Answer 17

-manipulates food & mixes it with salvia
-Assists in swallowing
-Detect taste, touch, and pressure
-Striated muscle under voluntary control

Question 18

characteristics of the pharynx

Answer 18

-common passageway for both food intake & air movement
-Digestive & respiratory passages come together then separate again
-Epiglottis: covers glottis: opening into the trachea
-mechanical digestion

Question 19

characteristics of esophagus

Answer 19

-Muscular tube for moving swallowed food from the pharynx to the stomach
-Moves food by peristalsis: wavelike contractions propel substances along a tubular structure
-mechanical digestion

Question 20

characteristics of stomach

Answer 20

-storage unit
-chemical and mechanical digestion

Muscular walls contract vigorously to mix food with digestive fluids
-Wall has rugae: deep folds that disappear as stomach fills to capacity
-Epithelial lining millions of gastric pits
-lead to gastric glands that produce gastric juices
-Food mixes with gastric juices becomes chyme
-Base of stomach narrow opening controlled by a sphincter
-allows only small release of chyme into intestines

Question 21

what is chyme

Answer 21

thick, semisolid food material that passes from stomach to small intestine

Question 22

characteristics of small intestine

Answer 22

-chemical and mechanical digestion
-Duodenum: first part of small intestine where chyme enters
-Duct brings bile & pancreatic juice into small intestine
-Bile emulsifies fat
-Slightly basic pH to neutralize chyme
-Enzymes from pancreatic juice & produced by intestine wall complete process of food digestion
-molecules now small enough to be absorbed into bloodstream and used

Question 23

characteristics of large intestine

Answer 23

-most digestion basically done, recycling
-mechanical digestion
-includes rectum and anus
-Absorbs water, salts, & some vitamins
-Stores undigestible material until it is eliminated as feces
-Large population of bacteria!
-Last section of colon rectum terminates in anus

Question 24

characteristics of pancreas

Answer 24

-chemical digestion
-Deep in abdominal cavity
-Elongated & somewhat flat organ
-Produce pancreatic juice

Question 25

what is pancreatic juice

Answer 25

-contains sodium bicarbonate, slightly basic and good at neutralizing acidic chyme -contains key digestive enzymes to break down and absorb small molecules

Question 26

characteristics of liver

Answer 26

-chemical digestion -Produces bile -Upper right section of diaphragm; largest gland -Contains about 100,000 lobules -Hepatic portal vein brings blood to the liver from small intestine -As the blood passes through the liver it is detoxified

Question 27

what is bile

Answer 27

contains more enzymes to break down molecules

Question 28

characteristics of gallbladder

Answer 28

-chemical digestion -Pear-shaped, muscular sac attached to surface of the liver -Stores excess bile -Water is resorbed so bile becomes thick, mucus-like material -Bile is needed -> gallbladder contracts -> releasing into duodenum via common bile duct

Question 29

Which animals would be classified as continuous feeders? a. All of these groups are all continuous feeders b. Clams, crickets, and dolphins c. Oysters, hummingbirds and planarian d. Worms, clams, and crayfish e. Clams, baleen whales, and oysters

Answer 29

e. Clams, baleen whales, and oysters

Question 30

The hepatic portal vein brings blood to the liver from the ________ and as the blood passes through the liver it is ________. a. The lungs; deoxygenated b. The mouth; acidified c. The pancreas; oxygenated d. The small intestine; detoxified

Answer 30

d. The small intestine; detoxified

Question 31

Which is not true of human salivary glands? a. There are three pairs that open by ducts into the mouth b. They produce an enzyme to begin the digestion of starch c. They can become inflamed and cause tonsillitis d. The production of saliva aids in the mechanical digestion process

Answer 31

c. They can become inflamed and cause tonsillitis

Question 32

The function of the human stomach is a. To begin the absorption of most small food molecules, especially sugars and alcohol b. To produce highly basic fluids to kill most bacteria c. Promotion of bacterial fermentation d. Storage of food and mixing with digestive fluids to continue chemical digestion e. Absorption of iron to build hemoglobin for red blood cells

Answer 32

d. Storage of food and mixing with digestive fluids to continue chemical digestion

Question 33

Which of the following statements about the large intestine is not true? a. Feces consists of about 25% water and 75% solids b. The large intestine is active in water absorption, removing about 95% of the water that enters it and returning it to the bloodstream c. The last section of the colon is the rectum, which terminates in the anus d. Contains a large population of bacteria which provide protection against pathogenic species

Answer 33

a. Feces consists of about 25% water and 75% solids