Digestive System Flashcards
saliva contains
salivary amylase
lingual lipase
antimicrobial agents
lysozyme
bicarbonate ions
mucin
salivary amylase function
begins chemical breakdown of polysaccharides into simple sugars
lingual lipase function
begins the breakdown of fats
lysozyme function
enzyme that works together with immunoglobulin A to break down cell walls of many bacteria
bicarbonate ion function
help saliva maintain pH that is optimal for salivary enzymes as well as other ions
mucin function
protein that helps to form gel-like coating that lubricates the bolus of food
esophagus is
25 cm tube extending from the pharynx to the stomach
esophagus function
passageway for food
esophagus secretes
mucus to aid in the transport of food
esophagus walls
4
mucosa
submucosa
muscular externa
adventitia
esophagus upper third composed of
skeletal muscle and is under voluntary control
esophagus lower third is
entirely smooth muscle
esophageal sphincters
one at superior end of esophagus and one at lower end of esophagus
what is the stomach
a muscular organ that can stretch to accommodate a high volume of food
what is the primary role of the stomach
the storage and mechanical break down of food
inner surface of the stomach
Mucosa- is folded into a series of ridges called rugae
rugae
series of ridges in the stomach. allow the stomach to expand as it fills with food
food in stomach
turns into chyme
pyloric sphincter
regulates passage of chyme into the small intestine
mucosa of stomach contains
gastric glands which open into numerous gastric pits
what are the 4 types of cells in gastric glands
mucous cells
parietal cells
chief cells
endocrine cells
endocrine cell function
also known as G-cellls. release hormones such as gastrin into the blood and do not contribute to gastric juices
parietal cell function
exocrine gland. secrete intrinsic factor and release hydrochloric acid
intrinsic factor
exocrine gland. required for absorption of vitamin B12 in small intestine
hydrochloric acid (HCl) function in stomach
lowers the pH of gastric juice to 1-3
why is an acidic environment required
for the activation of pepsinogen
chief cells function
secrete pepsinogen and gastric lipase
pepsin function
digestive enzyme that breaks down proteins into smaller peptide chains