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117 Cards in this Set
- Front
- Back
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What are the 5 functions (processes) of the digestive system?
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Ingestion
Mechanical processing Digestion Absorption Excretion |
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ingestion
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taking in of liquid or solid food
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mechanical processing
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crushing or shearing of food that does NOT change it chemically
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digestion
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chemical breakdown of food via catabolic reaction
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absorption
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moving nutrients from digestive tract to the blood and/or lymph
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excretion
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removal of waste materials
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What are the 4 layers of the digestive wall, starting from the innermost layer?
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Mucosa
Submucosa Muscularis externa Serosa |
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Describe this digestive layer: mucosa. (2)
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Touches food
Primary epithelium (nonvascular) |
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Describe this digestive layer: submucosa. (4)
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Dense, irregular connective tissue
Blood vessels Sensory neurons Glands (exocrine) |
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Describe this digestive layer: muscularis externa. (4)
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Thick bunch of muscle fibers
Smooth muscle (involuntary) Circular and longitudinal layer Performs peristalsis |
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Describe this digestive layer: serosa.
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Visceral serous membrane
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What are the 2 accessory organs of the small intestine?
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Liver
Pancreas |
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Are the salivary glands digestive organs or accessory organs?
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Accessory organs
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peristalsis
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combined circular and longitudinal smooth muscle contraction used to move bolus
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mesenteries
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folded sheets of peritoneum that hold intestines together and anchor them to body wall
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peritonitis
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inflammation of the peritoneal membrane; life-threatening and most common killer
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peritoneum
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transparent tissue that lines abdominal cavity
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Extrinsic regulation of the digestive system is controlled by what two systems?
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Nervous system
Endocrine system |
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What does the hard palate allow us to do?
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Breathe and chew simultaneously
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What is the purpose of chewing?
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Increase surface area by breaking food down into smaller pieces
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deglutition
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moving a bolus from the oral cavity into esophagus; act of swallowing, esp. food
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What kind of epithelia is the oral cavity lined with?
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Stratified squamous epithelia
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gomphosis
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peg joint that holds teeth in place
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periodontal ligament
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group of specialized connective tissue that hold tooth inside its bony socket
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cementum
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bony matrix that helps to hold teeth in place at the root
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What is the hardest biologically-made substance?
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Enamel
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Where are dentin and enamel made?
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From living cells in pulp cavity
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dentin
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mineralized matrix, like bone, that surrounds pulp cavity; below enamel
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enamel
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hard, white outer layer of the tooth; crystallized version of calcium phosphate
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gingiva
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tissue of the jaws that surround the base of teeth; gums
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What are the 3 types of teeth discussed in class?
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Incisors
Canines (cuspids) Molars |
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incisors
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made to cut or bite off food
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canines
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human teeth with deepest root; made for tearing
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molars
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flat tops for chewing and grinding
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bolus
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already chewed up and salivated on food
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What are 3 phases of deglutition?
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Buccal phase
Pharyngeal phase Esophageal phase |
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Identify what occurs during the following phase of deglutition.
Buccal |
Push bolus against hard palate, past soft palate, and back (into pharynx)
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Identify what occurs during the following phase of deglutition.
Pharyngeal |
Swallowing reflex from swallowing center (of brain) pushes bolus into esophagus
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Identify what occurs during the following phase of deglutition.
Esophageal |
Peristalsis moves bolus toward stomach
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How long is the esophagus?
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25 cm (10 in.)
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What kind of epithelium is the esophagus made of?
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Stratified squamous epithelium
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What is the volume of a stomach, generally?
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1.5 liters
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fundus
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large, hollow dome top of an organ
Note: Uterus and stomach both have a fundus. |
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cardiac sphincter
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the circular muscle that precedes the stomach
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TRUE or FALSE
Every entrance and exit to the digestive system has a sphincter. |
TRUE
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What are the 3 muscular layers of the stomach?
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Circular
Longitudinal Oblique (*) |
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rugae
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folds in the stomach muscosa that allow it to expand
Note: Also found in the bladder |
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gastric pit
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deep, narrow crevices that make up the opening of a gastric gland
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What is the stomach lining made of?
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Gastric pits with glands in them line the stomach and secrete gastric juice
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What are the 3 types of cells that line the gastric pit (gland)?
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Parietal cells
Endocrine cells Chief cells Tip: PEC |
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What type of cell are those that line the gastric pit (gland)?
A. Simple cuboidal B. Simple columnar C. Stratified squamous D. Stratified columnar |
Simple columnar
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In the gastric pit (gland), what function does the following cell have?
Parietal cell |
Make stomach acid (hydrochloric acid or HCl)
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In the gastric pit (gland), what function does the following cell have?
Chief cell |
Make enzymes, such as pepsinogen
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In the gastric pit (gland), what function does the following cell have?
Endocrine cell |
Make several hormones
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What is the main function of the small intestine?
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Nutrient absorption
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How long is the small intestine?
What is width of the small intestine? |
20-22 ft.
1 in. |
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What are the 3 parts of the small intestine and how long are they?
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Duodenum, 10 in.-1 ft.
Jejunum, 8 ft. Ileum, 12 ft. Tip: Remember order by this phrase: "Don't Jump In". |
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plicae circulares
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permanent folds in the small intestine covered with villi, which are in turn covered with microvilli
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Where do nutrients absorbed in the small intestine go?
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Capillary network and lacteal, located inside villi
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Which type of cell are the villi on the plicae circulares lined with?
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Simple columnar epithelial cell
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Where does the large intestine begin?
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At the cecum in the lower left quadrant, near appendix
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cecum
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a dead end pouch in the digestive system where material can go one way or the other
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What is the more common name for the large intestine?
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Colon
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What are the 4 parts of the large intestine?
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Ascending colon
Transverse colon Descending colon Sigmoid colon |
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taenia coli
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bands of longitudinal smooth muscle found on the large intestine
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Describe the lining of the large intestine.
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Simple columnar epithelia with goblet cells.
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What is it that you eat?
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Food
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What do you swallow?
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Bolus
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What goes into the small intestine?
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Chyme
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What comes out of your large intestine?
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Feces
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What human body structure changes food into a bolus?
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Oral cavity
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What organ changes a bolus into a chyme?
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Stomach
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What organ changes chyme into feces?
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Large intestine (colon)
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How does the large intestine change chyme into feces?
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It takes the water out of it
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cirrhosis
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buildup of scar tissue and nodules in the liver that interfere with its function; commonly caused by chronic alcoholism
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emesis
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vomiting
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hepatitis
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inflammation of the liver usually caused by a virus; 5 types A-E
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diverticulosis
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condition that occurs when small pouches (diverticula) push outward through weak spots in the colon
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diarrhea
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frequent, watery bowel movements
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gastric ulcer
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sore that erodes the lining of the stomach
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What extra layer of muscle does the stomach have compared to similar digestive organs?
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Oblique layer
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How do parietal cells make stomach acid (HCl)?
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What are the 3 phases of gastric secretion?
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Cephalic
Gastric Intestinal |
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What prompts the cephalic phase of gastric secretion?
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CNS via sight/smell/thoughts of food
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What is the purpose of the cephalic phase?
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Prepares the stomach for a bolus
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How does the cephalic phase prepare the stomach for a bolus? (3)
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Makes more mucus
Releases pepsinogen and HCl Stimulates gastrin |
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gastrin
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hormone that stimulates production of acids and enzymes; increases motility
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What initiates the gastric phase of gastric secretion?
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Arrival of the bolus in the stomach
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When does the cephalic phase subside?
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When you realize you are not getting any food
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What is the function of the gastric phase? (3)
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Enhance secretions from cephalic phase
Homogenize and acidify chyme Initiate digestion of proteins by pepsin |
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How does the gastric phase perform its function? (3)
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Increase HCl and pepsinogen production
Increase motility Initiate mixing waves |
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When a bolus arrives in the stomach during the gastric phase, what is the effect?
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Distention
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distention
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bloating or swelling of the abdomen
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homogenize
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to blend or puree
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What initiates the intestinal phase?
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Chyme entering small intestine
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What is the function of the intestinal phase? (2)
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Control rate of chyme entrance into duodenum
Alerts liver and pancreas to start secreting hormones CCK, GIP, and secretin |
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What occurs during the intestinal phase? (2)
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Slowed HCl and pepsinogen production
Reduction in gastric motility |
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How long is each phase of gastric secretion?
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Cephalic = Minutes
Gastric = 3-4 hours Intestinal = Hours |
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What stimulates cholecystokinin (CCK)?
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Arrival of chyme containing lipids and partially digested proteins in duodenum
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What are the 2 net effects of cholecystokinin (CCK)?
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Increase the secretion of pancreatic enzymes
Push pancreatic secretions and bile into the duodenum |
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What stimulates secretin?
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Chyme arriving in the duodenum
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What are the 3 primary effects of secretin?
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Stimulate production of alkaline buffers
Increase rate of bile secretion Slow down gastric secretion and motility |
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What initiates gastric inhibitory peptide (GIP)?
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Arrival of chyme containing fats and carbohydrates in the duodenum
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What are the 2 primary effects of gastric inhibitory peptide (GIP)?
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Stimulate release of insulin from pancreas
Slow down gastric secretion and motility |
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Identify the 2 functions of the liver pertaining to the digestive system.
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Produce bile salts
Detoxify blood via hepatic portal system |
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What connects the liver to the small intestine?
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Gall bladder (a bile duct)
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Describe the histology of the liver.
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Each liver lobule has sinusoids that empty into its own central vein
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Why does blood in the arteries and veins of a hepatic triad go in the same direction?
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They are NOT corresponding arteries and veins
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What are the 3 parts of a hepatic triad?
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Branch of hepatic portal vein
Branch of hepatic artery proper Bile duct |
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hepatic portal vein
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large vein through which oxygen-depleted blood from the stomach, the intestines, the spleen, the gallbladder, and the pancreas flows to the liver
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How does blood leave the hepatic portal system?
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By way of hepatic veins that go to the inferior vena cava
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Kupffer cells
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free macrophages of the liver
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What are the 2 digestive functions of the pancreas?
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Produce pancreatic juice
Neutralize acidic chyme via HCO3- |
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How acidic is the chyme coming out of the stomach?
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pH 1.5 - 2
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What produces the conscious urge to defecate?
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Arrival of feces in the rectum
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What is the 4-step process of the defecation reflex?
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Distention
Stimulation of stretch receptors Increased peristalsis Relaxation of internal anal sphincter |
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What is normal feces composed of?
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75% H2O
5% Bacteria 20% Undigested material |
