Bio 2, Cusic, 41.3-4

Front 1

where are the accessory glands in the mammalian digestive system located

Back 1

3, in the salivary glands

the pancreas

the liver

and the gallbladder

Front 2

how is food pushed along the alimentary canal?

Back 2

peristalsis

Front 3

peristalsis

Back 3

the alternating waves of contraction and relaxation in the smooth muscles lining the canal.

Front 4

some junctions occur between certain parts of the alimentary canal, what are they called

Back 4

sphincters

Front 5

sphincters

Back 5

act as drawstrings to close off the alimentary canal, these regulate passage of material between compartments

Front 6

the steps of ingestion initially begin where

Back 6

the mouth, or oral cavity

Front 7

Mechanical digestion begins where in humans

Back 7

it begins at the teeth, making the food easier to swallow and increasing surface area

Front 8

what does the presence of food stimulate

Back 8

it stimulates a nervous reflex that causes the salivary glands to deliver saliva through ducts to the oral cavity

Front 9

what else can stimulate salivary glands

Back 9

they can easily be triggered by a learned association between eating and the time of day, a cooking oder, and other stimuli (an example is the Pavlov dog)

Front 10

what does saliva initiate

Back 10

a chemical digestion that also protects the oral ccavity

Front 11

amylase

Back 11

an enzyme found in saliva that hydrolyzes starch (a glucose polymer from plants) and glycogen (a glucose polymer from animals) into smaller polysaccharides and disaccharide maltose

Front 12

where is the protective effect of saliva provided

Back 12

mucus, which his a viscous mixture of water, salts, cells, and slippery glycoproteins (carbohydrateprotein complexes) called mucins

Front 13

mucins

Back 13

the viscous mixture of water, salts, cells, and slipper glycoproteins that make up mucus

Front 14

what doe the mucus in saliva prot4ect

Back 14

the lining of the mouth from abrasions and lubricates food for easier swallowing

Front 15

name the additional components of saliva

Back 15

they include buffers, which help prevent tooth decay by neutralizing acid and antimicrobial agents (i.e. lysozyme) which protect against bacteria that enter the mouth with food

Front 16

bolus

Back 16

a chewed up ball of food that is coated in mucus

Front 17

pharynx

Back 17

or throat region, opens to two passageways: the esophagus and trachea

Front 18

esophagus

Back 18

this tube connects to the stomach, which contain both striated and smooth muscle

Front 19

when you swallow, there is a flap of cartilage, what is it called and what does it do

Back 19

its called the epiglottis, it covers the glottis- the vocal cord and the opening between them

Front 20

what directs the movement of the bolus through to the esophagus

Back 20

the larynx guides the movements, the upper part of the respiratory tract, that is recognized as the swallowing reflex directs each bolus into the entrance of the esophagus

Front 21

what does the stomach produce

Back 21

gastric juice

Front 22

what is the mixture of ingested food and digestive juice

Back 22

chyme

Front 23

the purpose of HCl in the stomach

Back 23

to disrupt the extracellular matrix that binds the cells together in meat and plant material

Front 24

in the stomach, what increases the exposer of peptide bonds

Back 24

the low pH denatures proteins in food, increasing their exposure of their peptide bonds

Front 25

two components of gastric juice

Back 25

HCl and protease

Front 26

protease

Back 26

a protein-digesting enzyme in the stomach called pepsin. This cleaves proteins into smaller polypeptides which leads to further digestion to individual amino acids that occur in the small intestine

Front 27

why doesn't the gastric juice destroy the stomach cells that make it

Back 27

the ingredients of gastric juice are kept inactive until they are they are released into the lumen (cavity) of the stomach

Front 28

what are the components of gastric juice produced by

Back 28

the cells in the gastric glands of the stomach- parietal cells & chief cells

Front 29

parietal cells

Back 29

these cells secret hydrogen and chloride ions which form HCl

Front 30

how do the parietal cells expel hydrogen ions into the lumen

Back 30

by using an ATP-driven pump

Front 31

what do chief cells release into the limen

Back 31

they release pepsin, an inactive form of pepsinogen

Front 32

what converts pepsinogen to active pepsin

Back 32

HCl by clipping off a small portion of the molecule and exposing its active site.

Front 33

after pepsin is active, what does it help HCl do?

Back 33

convert the rest of the pepsinogen into pepsin. this processes activates the production of more pepsinogen which form a more active enzyme, this is called positive feedback because it amplifies that effect of an initially small input

Front 34

when HCl and pepsin form within the stomach lumen, why aren't the cells that line the stomach damaged?

Back 34

even though the cells are vulnerable to the gastric juice as well as acid-tolerant pathogens, they are protected by secreting mucus

Front 35

how many days does it take to add a new epithelial layer to the stomach

Back 35

3 days, it replaces the cells that have been eroded by the acids

Front 36

what cause gastric ulcers

Back 36

once believed to have been from stress, was later to be discovered that it was from an acid-tolerant bacteria: helicobacter pylori, which is why most ulcers were able to be treated with antibiotics

Front 37

what facilitates chemical digestion

Back 37

gastric juice by the churning action of the stomach

Front 38

what is the cause of the irritation known as heartburn

Back 38

when a person experiences acid reflux which is a backflow of chime from the stomach to the lower esophagus

Front 39

what does the pancreas produce to aid in chemical digestion

Back 39

an alkaline solution rich in bicarbonate as well as several enzymes (protease, chymotrypsin, and protease that is secreted into the duodenum in inactive forms