overview of the digestive system

Question 1

how many groups of organs compose the digestive system? name them.

Answer 1

2 groups of organs: the gastrointestinal tract and the accessory digestive organs

Question 2

what is the GI tract or alimentary canal?

Answer 2

is a continuous tube that extends from the mouth to the anus

Question 3

from where to where does the GI tract contain food?

Answer 3

the GI tract contains food from the time it is eaten until it is digested and absorbed or eliminated from the body

Question 4

name the organs of the GI tract.

Answer 4

the mouth, pharynx, esophagus, stomach, small intestine, and large intestine

Question 5

what is the length of the GI tract?

Answer 5

about 5-7 meters (16.5-23 ft) in a living person

Question 6

why is it longer in a cadaver ( about 7-9 meters or 23-29.5 ft)?

Answer 6

because the muscles along the wall of the GI tract organs are in a state of tonus (sustained contraction)

Question 7

name the accessory digestive organs.

Answer 7

the teeth, tongue, salivary glands, liver, gallbladder, and pancreas

Question 8

What do the teeth and tongue do?

Answer 8

teeth aid in the physical breakdown of food, and the tongue assists in chewing and swallowing

Question 9

do the other accessory digestive organs come into direct contact with food?

Answer 9

they never come into direct contact with food

Question 10

through what do the secretions that they produce or store flow into the GI tract and aid in what?

Answer 10

through ducts and aid in the chemical breakdown of food

Question 11

how many basic processes does the digestive system perform?

Answer 11

6 basic processes

Question 12

1) ingestion

Answer 12

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Question 13

what does this process involve?

Answer 13

taking foods and liquids into the mouth (eating)

Question 14

2) secretion

Answer 14

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Question 15

what do cells within the walls of the GI tract and accessory organs secrete and into what?

Answer 15

each day, cells within the walls of the GI tract and accessory organs secrete a total of about 7 liters of water, acid, buffers, and enzymes into the lumen of the tract

Question 16

3) mixing and propulsion

Answer 16

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Question 17

what mixes food food and secretions and propel them toward the anus?

Answer 17

alternating contractions and relaxation of smooth muscle in the walls of the GI tract

Question 18

what is the ability of the GI tract to mix and move material along its length termed as?

Answer 18

motility

Question 19

4) digestion

Answer 19

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Question 20

what do mechanical and chemical processes do to ingested food?

Answer 20

they break down ingested food into small molecules

Question 21

what happens in mechanical digestion (teeth, smooth muscles of the stomach and small intestine)?

Answer 21

the teeth cut and grind food before it is swallowed, and then smooth muscles of the stomach and small intestine churn the food

Question 22

what is its result?

Answer 22

as a result, food molecules become dissolved and thoroughly mixed with digestive enzymes

Question 23

what happens in chemical digestion?

Answer 23

the large carbohydrate, lipid, protein, and nucleic acid molecules in food are broken down into smaller molecules by digestive enzymes

Question 24

5) absorption

Answer 24

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Question 25

what is absorption?

Answer 25

the entrance of ingested and secreted fluids, ions, and the small molecules that are products of digestion into the epithelial cells lining the lumen of the GI tract

Question 26

where do the absorbed substances pass into, then into where and what do they circulate?

Answer 26

the absorbed substances pass into interstitial fluid and then into blood or lymph and circulate to cells throughout the body

Question 27

6) defecation

Answer 27

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Question 28

from where do wastes, indigestible substances, bacteria, cells shed?

Answer 28

wastes, indigestible substances, bacteria, cells shed from the lining of the GI tract

Question 29

what happens to the digested materials that were not absorbed?

Answer 29

leave the body through the anus in a process called defecation

Question 30

what are the eliminated material called?

Answer 30

feces (stool)