Digestive Physiology (7)

Question 1

What does the alimentary canal do? (aka gastrointestinal tract)

Answer 1

digest and absorbs food

Question 2

What do the accessory organs do?

Answer 2

assist the alimentary canal in the process of digesting and absorbing food

Question 3

Order of the alimentary canal (or gastrointestinal tract)

Answer 3

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

Question 4

accessory organs

Answer 4

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

Question 5

functions of the digestive tract

Answer 5

ingestion, propulsion, mechanical digestion, chemical digestion, absorption, defecation

Question 6

mechanical digestion

Answer 6

physical breakdown of feedstuffs
- teeth, stomach, intestines

Question 7

chemical digestion

Answer 7

macromolecules to monomers
- enzymes from saliva, stomach, pancreas, intestines
- result: polysaccharides to monosaccharides, proteins to amino acids, fats to glycerol and fatty acids

Question 8

motility

Answer 8

muscle contractions that break up food, mix it with enzymes, and keep it moving

Question 9

secretion

Answer 9

digestive enzymes and hormones

Question 10

membrane transport

Answer 10

absorption of nutrients

Question 11

control of the gastrointestinal tract is through…

Answer 11

• nervous control
• hormones
• paracrine secretions

Question 12

nervous control of gastrointestinal tract

Answer 12

• enteric nervous system
• intrinsic controls: short reflexes mediated by local nerve plexuses (gut brain)
• extrinsic control: long reflexes involving CNS centers

Question 13

peritoneum

Answer 13

serous membrane of the abdominal cavity
split into visceral (inner layer right up against organs) and pariental (outer layer)

Question 14

peritoneal cavity

Answer 14

lubricates digestive cavity; slide across one another

Question 15

mesentery

Answer 15

fold of peritoneum that wraps around intestines
- lots of nerves, veins, arteries
- keeps intestines from kinking
- delivers nutrients away from intestine

Question 16

what are the functions of the oral cavity?

Answer 16

ingestion, mechanical digestion (except birds), propulsion initiated by swallowing, salivary amylase (chemical breakdown of starch)
- pharynx and esophagus pass food to stomach

Question 17

what are the functions of the tongue?

Answer 17

acquisition of food and water, repositioning and mixing food, formation of bolus, initiation of swallowing, speech, taste

Question 18

bolus

Answer 18

one ball of what you’ve been chewing

Question 19

papillae and taste buds on ____ surface of tounge

Answer 19

dorsal

Question 20

_____ glands secrete saliva, tonsils in root (of tounge)

Answer 20

lingual

Question 21

Saliva

Answer 21

hypotonic solition of 97-99.5% water and solutes
- pH 6.8-7.0
- electrolytes: Na+, K+, Cl-, phosphate, and bicarbonate

Question 22

function of mucus in oral cavity

Answer 22

aids in swallowing

Question 23

lysozyme (in saliva)

Answer 23

enzymes that kills bacteria

Question 24

immunoglobulin A (in saliva)

Answer 24

inhibits bacteria growth

Question 25

salivary amylase

Answer 25

starch digestion requires neutral pH

Question 26

layers of gastrointestinal tract innermost to outermost

Answer 26

mucosa, submucosa, muscularis externa, serosa

Question 27

mucosa

Answer 27

innermost layer of cells

Question 28

submucosa

Answer 28

vessels and nerves; flexible movement during peristalsis (contractions that help move food)

Question 29

muscularis externa (peristalisis/segmentation)

Answer 29

contraction and relaxation; physically break down food and propel it forward

Question 30

serosa

Answer 30

epithelial layer and connective tissue; adheres tract into place; connection

Question 31

esophagus

Answer 31

straight muscular tube connecting pharynx to stomach - nonkeratinized stratified squamous epithelium - esophageal glands in submucosa - skeletal (striated) muscle in upper part, smooth at bottom (varies by species)

Question 32

deglutition (swallowing)

Answer 32

buccal phase: bolus to oropharynx - conscious control pharyngeal-esophageal phase - subconscious control

Question 33

what moves food from mouth to anus

Answer 33

peristalsis

Question 34

what is peristalsis

Answer 34

how food is propelled - circular smooth muscle contracts and relaxes in waves to propel food forward - and longitudinal muscle moves it along like a water wiggler

Question 35

segmentation

Answer 35

subdivide, break up, and mix contents - localized contraction of circular muscle of the GI tract - contractions isolate small sections of the intestine, moving contents back and forth

Question 36

stomach

Answer 36

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