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the digestive system
digestive system
39
Anatomy
Undergraduate 2
01/23/2011

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Cards

Term
What are the functions of the digestive system?
Definition
ingestion, movement of food, digestion, absorption, defecation
Term

What is mechanical digestion?

Definition

maceration by teeth, churning by stomach and small intestines

Term
What is chemical digestion?
Definition
catabolic reactions which break down large molecules into small ones
Term
How is the digestive system organized?
Definition
contains a GI tract (mouth, pharynx, esophagus, stomach, small and large intestines) and accessory structures (teeth, tongue, salivary glands, liver, gall bladder, and pancreas)
Term
What are the 3 layers of the GI tract?
Definition
mucosa, submucosa, muscularis
Term
What kind of tissue is in the mucosa layer?
Definition
it is in direct contact, stratified squamous epithelium in mouth, esophagus, and anus canal. simple columnar epithelium in stomach and intestines= secretion and absorption
Term
What is the muscularis mucosae?
Definition
a thin layer of smooth muscle which undulates, creating peaks and valleys which serve to increase surface area
Term
What is the lamina propria?
Definition

 

 is an underlying layer of areolar CT.  Supports the epithelium, connecting it to the muscularis mucosae.  Contains abundant blood & lymphatic vessels

 

Term
What is the submucosa?
Definition

 

Areolar CT that binds the mucosa to the muscularis, Highly vascularized, Contains part of the submucosal plexus (Meisnner’s) - autonomic nerve supply to the muscularis mucosae which serves to control secretions


 

Term
What is the muscularis?
Definition

*mouth, pharynx, superior esophagus-composed of skeletal muscle for voluntary movement

*external anal sphincter- composed of skeletal muscle for voluntary defecation

*rest of GI tract except stomach-smooth muscle arranged in 2 sheets=inner sheet of circular fibers, outer sheet of longitudinal fibers

*stomach 3 layers- inner oblique, middle circular, outer longitudinal

*contains myenteric plexus which controls GI tract motility

Term
What is serosa?
Definition
superficial layer of portions of GI tract suspended above the abdominopelvic cavity, composed of CT and epithelium
Term
What is the peritoneum and what does it contain?
Definition
largest serous membrane in body=CT +simple squamous epithelium, parietal & visceral peritoneum, mesentery, falciform ligament, lesser and greater omentum
Term
what does the parietal and visceral peritoneum line?
Definition

parietal=lines abdominopelvic cavity

visceral=covers some organs in the cavity and is their serosa

Term
what is mesentery?
Definition

Mesentery is an outward folding of the visceral peritoneum covering the intestines, binding the intestines to one another & to the posterior abdominal wall


Term
what is the falciform ligament?
Definition

Falciform ligament is another folding that connects the liver to the anterior abdominal wall & the diaphragm


Term
what is the lesser and great omentum?
Definition

lesser=suspends the stomach and the duodenum from the liver

greater=drapes over the transverse colon and small intestines (lots of FAT!)

Term
what are the organs of the GI tract?
Definition
mouth, tongue, teeth, pharynx, esophagus, stomach, pancreas, liver, gall bladder, small intestines, large intestines
Term
what is the mouth lines with?
Definition
nonkeratinized squamous epithelium
Term
what is the tongue composed of?
Definition
skeletal muscle covered with mucous membrane
Term
what is a papillae?
Definition
projections of the lamina propria covered with epithelium
Term
what are the 3 papillae on the tongue and what do they contain?
Definition

filiform=contain no taste buds

fungiform= most contain taste buds

circumvillate= all contain taste buds

Term
what does saliva do?
Definition
lubricates, dissolves, and initiates chemical breakdown of food
Term
what are buccal and salivary glands?
Definition

buccal=minor glands in the mucous membrane lining the mouth, small amounts of saliva

salivary=major glands lie outside of the mouth, saliva is moved by ducts into the mouth

Term
what are the 3 salivary glands?
Definition

Parotid, Submandibular, Sublingual

Term
what forms the solute portion of saliva?
Definition
salivary amylase, lingual lipase, lysozyme
Term
what kind of joints are teeth?
Definition
gomphosis joints
Term

what are teeth composed of and what are their function?

 

Definition
sockets lined with periodontal ligaments(dense CT), 3 portions-crown, neck, root, teeth composed of dentin, dentin of crown covered by enamel, function is mastication- physical digestion of food
Term
what is the pharynx covered with and what is it subdivided into(from mouth to esophagus)?
Definition
stratified squamous epithelium, oropharynx, hypopharynx
Term
what is deglutition?
Definition
a mechanism to move food from mouth to stomach
Term
what are the 3 stages of deglutition?
Definition

voluntary stage=bolus is moved into the oropharynx

pharyngeal stage=involuntary passage of the bolus through the pharynx into the esophagus

esophageal stage= involuntary passage of the bolus through the esophagus into the stomach 

Term
where does the esophagus lie?
Definition
posterior to the trachea
Term
whats are the layers of the esophagus?
Definition
mucosa=stratified squamous epithelium, lamina propia, muscularis mucosae. near stomach mucus glands will appear
submucosa=areolar CT, blood vessels, mucous glands
muscularis=superior third-skeletal, intermediate third-skeletal & smooth, inferior third-smooth
adventita=connective tissue
Term
what are the functions of the esophagus?
Definition
secretes mucus, does not produce digestive enzymes and does not carry out absorption, upper esophageal sphincter regulates passage of food from hypopharynx into esophagus, esophageal stage accomplished by peristalsis
Term
what is peristalsis?
Definition
involuntary muscle movement 
Term
how does peristalsis work in the esophagus?
Definition
contraction of circular muscles propel bolus inferiorly, while longitudinal muscles inferior to bolus contract, widening esophagus in this are to receive bolus. blous is regulated at the esophagus-stomach junstion by the gastroesopageal sphincter
Term
what does the stomach connect?
Definition
esophagus to duodenum
Term
what does the stomach contain?
Definition
cardia, fundus, body, pylorus
Term
what are the 2 parts of the pylorus?
Definition

pyloric antrum=connects to body of stomach

pyloric canal=leads to duodenum. pylorus communicates with duodenum via pyloric sphincter 

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