Studied by 13 peoplemouth, oral cavity
Where does the digestive system begin at? What is this also known as?
cheeks, hard palate, soft palate
What is the mouth formed by?
three, parotid, submandibular, sublingual
How many salivary glands are there? What are they?
begin chemical digestion, lubricate food
What are the functions of the saliva? (2 things)
water, mucus, enzymes that destroy bacteria, enzymes that start chemical digestion
What does saliva contain? (4 things)
an enzyme that begins starch breakdown
What is salivary amylase?
mouth, when it hits the acid in the stomach, fat breakdown
Where is lingual lipase released? When is it activated? What does it begin?
floor of the oral cavity, receptors, taste
What does the tongue form? What does it have? What are they for?
accessory digestive organ
What is the tongue considered?
it is needed for digestion but food does not pass through it
Why is the tongue considered an accessory digestive organ?
muscle, mucous membrane
What is the tongue composed of?
outside of the tongue, but connect to it
Where do extrinsic muscles of the tongue originate?
move tongue from side to side and in and out
What do extrinsic muscle of the tongue do?
within tongue
Where do intrinsic muscles originate and insert?
alter size and shape of tongue
What do intrinsic muscles of the tongue do?
accessory digestive organs
What kind of organ are the teeth?
in sockets in the gingiva which covers the mandible and maxilla
Where are the teeth located and what does it cover?
chewing, mastication
What does mechanical digestion result from? What is this also known as?
a soft, flexible mass, bolus, it is easily swallowed
What results from chewing? What does it also known as? What happens to this?
passes from the mouth into the pharynx
Where does the bolus go?
muscle, mucous membrane
What is the pharynx made of? What is it lined by?
three, nasopharynx, oropharynx, laryngopharynx
How many parts is the pharynx divided into? What are they?
propel food into esophagus
What do the contractions in the pharynx do?
tongue pushes food backward against palate
What happens during the voluntary stage?
food goes into oropharynx, medulla oblongata is stimulated, soft palate and uvula move up to prevent food from entering nasopharynx, epiglottis closes so food does not enter trachea, esophageal sphincter relaxes, food enters esophagus
What happens during the involuntary stage? (6 things)
a muscular tube
What is the esophagus, essentially?
posterior
Where does the esophagus lie in relation to the trachea?
mediastinum
Where does the esophagus travel through?
anterior
Where does the esophagus lie in relation to the vertebral column
diaphragm
What does the esophagus pierce through?
superior portion of the stomach
Where does the esophagus end?
a wave like motion of muscle contractions, forces food down esophagus
What is peristalsis? What does it do?
food enters stomach
What happens when the lower esophageal sphincter relaxes?
lower esophageal needs to relax
What needs to happen in order for food to enter the stomach?
4-8 seconds
How long does it take for food to go from the mouth to the stomach?
mixing, storage, chemical digestion, secretes the hormone gastrin
What are the four functions of the stomach?
cardia, fundus, body, pylorus
What are the four main regions of the stomach?
ridges
What are the rugae of the stomach?
duodenum
What does the pyloric sphincter open up to?
pyloric sphincter
What opens up to the duodenum?
four
How many basic cell layers does the stomach have?
secretory cells called gastric glands, line narrow channels called gastric pits
What specialization does the stomach have? What do these do?
mucous neck cells, parietal cells, enterochromaffin-like cells, chief cells, D cells, G cells
What are the 6 secretory cells in the stomach?
mucus, bicarbonate
What does the mucous neck cell secrete?
gastric acid, hydrochloric acid
What do parietal cells secrete?
histamine
What do enterochromaffin-like cells secrete?
pepsin, gastric lipase
What do chief cells secrete?
somatostatin
What do the D cells secrete?
gastrin
What do the G cells secrete?
gastric juice, 2-3 quarts
What do gastric glands secrete? How much is created per day?
continue the chemical breakdown
What does gastric juice do?
smaller polypeptide chains, triglycerides, fatty acids, monoglycerides
What are proteins broken up into? (4 things)
chyme
What is food + gastric juices?
yes
Do chemical and mechanical digestion occur at the same time?
rhythmic
What kind of contractions does the stomach have?
duodenum, regular intervals
What are small smounts of chyme passed into? At?
2-4 hours
How long does it take for the stomach to empty?
very little
Is there very little or very large absorption in the stomach?
water, small ions, certain drugs, alcohol
What is typically absorbed by the stomach? (4 things)
Note
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