CH 16 The digestive system
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CH 16 The digestive system
What are the digestive functions and related processes?
What is the name of the inner lining of the digestive tract?
A mucous membrane
What fingerlike projections extend into the intestine and what is their purpose?
Villi and they increase the area for absorption
The oral cavity, pharynx, esophagus, and anus are lined by what type of epithelium
Stratified squamous epithelia
The remainer of the digestive tract is lined by what?
simple columnar epithelium and contains secretory cells
What is the second layer of loose connective tissue that is immediately deep to the muscularis mucosae?
Contains large blood vessels and lymphatic vessels
What is the band of smooth muscle cells arranged in an inner circular layer and an outer longtitudinal layer?
What is a serious membrane that covers the muscularis externa?
What suspends portions of the digestive tract? They are double sheets of serous membrane
What is the process of moving material along the tract by contractions?
What is the mechanical mixing of foods by muscular contractions in the digestive tract?
What does the oral cavity do?
Senses and analyzes material before swallowing
Mechanically processes material
Lubricates material by mixing it with mucus and saliva
Begins digestion of carbs and lipids with enzymes
what is another name for...
Primary functions of the tongue
Mechanical processing by compression, abrasion, and distortion
Manipulation to assist in chewing and to prepare the material for swallowing
Sensory analysis by touch, temp and taste
What are the three glands in the mouth
What does saliva contain?
IgA Salivary antibodies
THe parotid glands secrete what?
Salivary amylase, breaks down starches
The submandibular and sublingual salivary do what?
More buffers and mucus
saliva is regulated by what nervous system?
What part of the tooth marks the boundary between the root and crown?
What covers the crown?
what is each tooth made of?
Where does the tooth get its nutrients as the dentin does not contain cells?
The central pump cavity, through the root canal at the base of each tooth which has nerves and vessels
what covers the dentin of the root, providing protection and anchoring the periodontal ligament?
What are the blade shaped teeth found in the front of the mouth?
What are conical teeth used for tearing or slashing?
What is the opening in the diaphragm that the esophagus runs through?
What is the esophagus lined with?
squamous stratified epithelium
Which esophageal spincter is active contraction and prevents backflow of materials from stomach into esophagus?
Lower esophageal sphincter
What are the steps of deglutition?
Bolus enters stomach
What are the primary functions of the stomach?
Temporary storage of ingested food
Mechanical breakdown of ingested food
Breakdown of chemical bonds in food items through acids and enzymes
Production of intrinsic factor
What is the smallest part of the stomach?
What is the bulge of the stomach superior to the cardia?
What sphincter regulates the flow of chume between the stomach and small intestine?
When the stomach is relaxed or empty, the mucosa contains a number of prominent ridges or folds called ______
This allows the stomach to expand
What cheif cells secrete a protein that is secreted into the stomach lumen that is converted.
Pepsinogen and is converted to pepsin
What are the stages ofgastric secretion?
What occurs in the cephalic stage?
Sight, smell, taste or thought of food initiates this. Gastric juice production accelerates and salivation occurs
What occurs in gastric activity during the gastric phase?
Food arrives in the stomach, stretch receptors are stimulated. Myenteric plexus stimulates mixing waves in the stomach wall. Gastrin is released.
Chyme is produced
What occurs during the intestinal phase?
Chyme enters small intestine.
Enterogastric reflex occurs and inhibits neural stimulation of gastrin production and gastroc motility
What are the three segments of the small intestine?
Where is the bulk of of chemical digestion and nutrient absorption occur in the small intestine?
What hormone is stimulated by vagus nerve or arrival of food in the stomach.
Or arrival of chyme containing large quantities of undigested proteins?
Where is gastrin originated and what does it target?
Stomach or duodeum
What are the effects of Gastrin?
Stimulates production of acids and enzymes, increases motility
What stimulates secretin?
Arrival of chyme in the duodenum
Where does secretin originate and what does it target?
Originates in duodenum
targets pancrease, stomach and liver
Which GI hormone stimulates production of alkaline buffers, inhibits gastric secretion, increases rate of bile secretion
What stimulates the arrival of chyme containing lipids and partially digested proteins?
What does Cholecytokinin (CCK) target?
Pancreas, gallbladder, duodenum, stomach, CNS
What does the arrival of chyme containing large quantities of fats and glucose secrete homonally?
Gastric inhibitory peptide GIP
What effects does Gastric Inihibitory peptide (GIP) do?
Stimulates release of insulin
Inhibits gastric secretion and motility
What enzymes secreted from the Pancrease digest sugars and starches?
What enzymes from the pancreas break down proteins?
What are the four lobes of the liver called
caudate and quadrate lobes
What marks the division between the left and right lobes?
The galbladder is located under which lobe of the liver?
What is the basic functional unit of the liver?
What are liver cells called?
What are the phagocytic cells in the liver called?
Where does the bile realeased from the __________ leave the liver through?
Common hepatic duct
Bile in the common hepatic duct may either flow into the ______ or _______
common bile duct and into the duodenum or
cystic duct which leads to the gallbladder
What are the liver functions?
What are the main functions of the large intestine
The reabsorption of water and compaction of intestinal contents into feces
The absorption of important vitamins freed by bacterial action
The storage of fecal matter
What are the three parts of the large intestine?
What is the small pouch at the start of the cecum?
What part of the descending colon empties into the rectum?
What are the three longtitudinal bands of smooth muscle that run along the large intestine?
What are the two anal sphincters and which are voluntarily controlled?
Internal and external
External is voluntarily controlled
Bacteria in the colon generate what three vitamins that supplement dietary supply?
Vitamin K, clotting factors
Biotin, glucose metabolism
Vitamin B5, steroid hormones and neurotransmitters
What are the building blocks of proteins?
Digestive enzymes break the bonds in proteins and lipids through what process?
A product left after triglycerides are broken appart, resulting the mixture of fatty acids and monogluycerides interacting with bile salts are
What are Fat soluble vitamins?
A, D, E and K
Which vitamin cannot be absorbed by intestinal mucosa unless bound by intristic factor.
During aging, the division rate of epithelial stem cells increases
True or false
When aging smooth muscle tone decreases?
true or false