The Upper Digestive System (Lecture 20) Flashcards
What is part of the GI tract?
oral cavity, pharynx, esophagus, stomach, small intestine, large intestine
What does GI stand for?
gastrointestinal
What are the accessory digestive organs?
teeth, tongue, salivary glands, pancreas, liver, gallbladder
What is ingestion?
bringing food in
What is propulsion?
food going through the GI tract
What are the two types of propulsion?
swallowing and peristalsis
What is peristalsis?
contraction of the tube of the GI tract to move food; pushing tooth paste out from the bottom
What is mechanical digestion?
breaking food up
What are the kinds of mechanical digestion?
chewing, churning, segmentation
Where does churning happen?
the stomach
What is segmentation?
movement of smooth muscle in the small intestine; cap toothpaste and mix it up
What is absorption?
bringing food particles into the blood
Where does most of absorption happen?
small intestine
What does the small intestine absorb?
nutrients and water to blood vessels and lymph vessels
What does the large intestine absorb?
water to blood vessels
What does the large intestine do?
condenses stuff we can’t absorb
What is defecation?
pooping
What is the lumen?
the space in the GI tract
What is the mucosa?
epithelial lining closest to the lumen
What does the mucosa do?
performs secretion and absorption
What is the submucosa?
vascularized and innervated connective tissue
What is the muscularis?
inner circular and outer longitudinal layers of smooth muscle
What is the serosa?
visceral peritoneum
What is the histology of the small intestine?
lumen, mucosa, submucosa, muscularis, serosa
What is the serosa also known as?
adventitia
What are the lips and oral cavity lined with?
non-keratinized stratified squamous epithelium
What is the first site of mechanical and chemical digestion?
oral cavity
What is the body of the tongue?
unattached part
What is the root of the tongue?
attached part close to the epiglottis
What is the apex of the tongue?
the very top
What controls the salivary glands?
ANS
What does a parasympathetic response secrete from salivary glands?
watery solution
What causes parasympathetic response of the salivary glands?
smell of favorite food
What does a sympathetic response secrete from salivary glands?
thick saliva
What causes a sympathetic response of the salivary glands?
nervousness
What gland produces the most saliva?
submandibular gland
How much saliva does the submandibular gland produce?
60-70%
How much saliva does the parotid gland produce?
25-30%
How much saliva does the sublingual gland produce?
3-5%
How much saliva is produced per day?
1.5 L
What does saliva do?
wets and binds food into a bolus, cleans and lubricates oral cavity, kills harmful microorganisms
What do enzymes in saliva do?
begin digestion of starch
How many primary teeth do we have?
20
How many permanent teeth do we have?
32
What numbers of teeth are considered the wisdom teeth?
1,16,17,32
What is the hardest substance of the body?
enamel
What are the regions of the teeth?
crown, neck, root
What substance is in each region of the tooth?
dentin
What does the root canal house?
connective tissue, nerves, blood vessels
What does cementum do?
helps bind root of teeth to the bone
What is the nasopharynx lined with?
pseudostratified ciliated columnar epithelium
What is the oropharynx and laryngopharyns lined with?
stratified squamous epithelium
What is the pharynx known as?
the throat
What structures do food and air go through?
oropharynx and laryngopharynx
What is deglutition?
swallowing
What happens during the voluntary phase of deglutition?
bolus of food is pushed by tongue against the hard palate and moves toward oropharynx
Where does the voluntary phase of deglutition happen?
oral cavity
What is the pharyngeal phase of deglutition?
soft palate and uvula close off the nasopharynx, larynx and hyoid elevate and the epiglottis closes over the laryngeal opening
What happens during the esophageal phase of deglutition?
peristaltic contractions of the esophageal muscle push the bolus toward the stomach
What is the esophagus lined with?
stratified squamous epithelium
What happens in the esophagus?
peristalsis
What is the esophagus?
a muscular tube
What type of muscle does the upper one-third of the esophagus have?
skeletal muscle
What type of muscle does the middle one-third of the esophagus have?
skeletal and smooth muscle
What type of muscle does the lower one-third of the esophagus have?
smooth muscle
What does the superior esophageal sphincter do?
closes to prevent air from getting into the GI tract
What does the inferior esophageal sphincter do?
closes to prevent acidic food from coming back up
What is the esophageal hiatus?
an opening in the diaphragm
What is reflux esophagitis?
acidic contents regurgitate into the esophagus
How long does the stomach store food?
3-4 hours
What are the functions of the stomach?
stores food, mechanical digestion, chemical digestion, limited absorption
What does the stomach do in mechanical digestion?
churns food with gastric juice
What does the stomach do in chemical digestion?
initiates protein digestion
What starts protein digestion?
pepsin
How many layers of muscle does the stomach have?
three
What are the rugae of the stomach?
folds in the stomach
What do the rugae of the stomach do?
increase surface area
What are peptic ulcers?
an erosion of stomach or duodenal mucosa
What is a perforating ulcer?
an erosion through the entire wall
What is the stomach lined with?
simple columnar epithelium with gastric pits and gastric glands
What do surface mucous cells do?
secrete mucin to protect the stomach wall
What do parietal cells do?
secretes hydrochloric acid and intrinsic factor
What do chief cells do?
secrete pepsinogen
What is pepsinogen?
inactive form of pepsin
What does pepsinogen do?
turns into pepsin in an acidic environment
What do enteroendocrine cells do?
secrete gastrin into the bloodstream
What does gastrin do?
stimulates parietal cells to produce hydrochloric acid and chief cells to produce pepsinogen and stimulates smooth muscle
