Digestive System

Total Flash Cards » 45

What are 4 functions of the digestive system?


1. ingestion- food/liquid enter digestive tract, 2. mechanical processing- chewing, churning, mixing, 3. digestion-chemical, enzymatic breakdown of food, 4. secretion-by glandular accessory organs


And the other 4 functions?


5. Absorption-organic molecules, electrolytes, vitamins, 6. compaction-dehydration of indigestible materials, waste; 7. excretion- waste products secreted into the digestive tract; 8. defecation-elimination of fecal material from the body


What is the histology (tissue) of the digestive tract?


mucosa, submucosa, muscalaris externa, serosa


What is the mucosa made up of?


Mucosal epithelium, lamina propia, and muscularis mucosa. Plica folds the mucosa so it can absorb more


What is the submucosa made of?


areolar tissue surrounding musclaris mucosa, contains blood vessels, lymphatics, exocrine glands


What is 'Peristalis'?


Process which moves bolus by wavelike contractions in the musclaris externa, circular and longitudinally oriented muscles,


What is segmentation


Process whereby the circular muscles of muscalaris externa churn and mix the bolus to break it up


What makes the stomach growl?


Peristalis begins two hours no matter what after you eat, except now the digestive tract is empty


What is the difference between the parietal and and visceral peritoneum?


Parietal peritoneum is on the inner lining of the digestive tract's body wall, visceral peritoneum/serosa is located on the outer lining of the tract




fused, double sheets of peritoneal membrane


Locations of the specific mesentaries?


lesser omentum- lies between stomach and liver, greater omentum- "fatty apron" that hangs beneath the stomach, disgusting looking; Mesentary proper-suspends and wraps most of the small intestine; Mesocolon- suspends and wraps part of the large intestine


What are the functions of the mesentary?


stabilize the organs and provide access routes for veins, arteries and nerves to the digestive tract


Intraperitoneal organs


stomach, liver, jejunum, ileum, transverse colon, sigmoid colon, appendix


retroperitoneal organs (fused with posterior abdominal wall


doudenum, pancreas, ascending colon, descending colon, kidneys, adrenal glands


Digestive functions of the oral cavity


analysis of ingested products (tongue), mechanical processing (chewing), lubrication, digestion of carbohydrates


What are the three salivary glands and where are they located?


1) Parotid salivary glands-deep in the head 2)sublingual-under the tongue 3)submandibular-in the jaw area under sublingual


1st phase of swallowing


Buccal phase- compression of bolus against hard palate, elevation of soft palate and retraction of tongue


2nd phase of swallowing


pharyngeal phase- bolus contacts posterior pharyngeal wall, elevation of larynx, folding of epiglottis


3rd phase of swallowing


esophageal phase- opening of upper esophagal sphincter, peristalsis, opening of lower espohagual sphincter


Functions of the stomach


1. bulk storage, 2. mechanical breakdown of digested foods 3. chemical digestion begins 4. beginning absorption of water, aspirin, alcohol


define rugae


longitudinal folds in the mucosa that allow the expansion of the gastric lumen


What are the four types of cells located in the stomach?


mucous, parietal cells break down acids, Chief cells=pepsinogen, Enteroendocrine cells=gastrin (hormone)


Define peptic ulcer


a sore or hole in the lining of the stomach caused by bacteria


What are the sections of the small intestine


doudenum (10in) Jejuneum (8ft) ileum (12ft)


functions of the doudenum


the "mixing bowl', recieves chyme from the stomach and digestive enzymes (bile) from pancreas and liver


functions of jejunuem


where bulk of chemical and nutrient absorption takes place


functions of ileum


controls flow of material into the large intestine


small intestine secretions


goblet cells-secrete mucous; enteroendocrine cells-secrete many hormones


divisions of the large intestine


1) Cecum 2) colon=ascending, transverse, descending, sigmoid 3) rectum=anal canal and anus


large intestine functions


1) reabsorption of water and electrolytes 2) compaction of intestinal contents into feces 3) absorption of vitamins 4) storage of fecal material before defecation


define epiploic appendages


fat pouches that hang off the large intestine


define Haustra


sacules between bands of circular muscles are accentuated taenia coli muscle contractions


movement through the large intestine


1) slow passage of material through with Haustral Churning 2) periodic mass movement via powerful muscle contractions 3) distension of rectal wall to stimulate conscious urge to defecate


define difference between Internal and External anal sphincter


Internal- involuntary smooth muscle External- voluntary smooth muscle whose relaxation allows for defecation


define diverticulitis


inflammation of abnormal pouches (diverticulum) that are not even normally found in the large intestine


Functions of the liver


performs 200+ functions relating to 1) metabolic regulation 2) hematological regulation=blood reservoir and filter/remover of dead blood cells and 3) bile production


How is bile drained from the liver?


drained through right and left hephatic ducts into the common hephatic duct


where does bile emanate after a fatty meal is eaten


comes from gallbladder (where it's stored) by way of common bile duct which empties into the doudenum. helps facilitate breakdown of lipids


define hephatic portal system


blood flowing from veins in digestive system drain into the liver by way of the hephatic portal vein, blood is then filtered by sinusoids


define cirrhosis of the liver


destruction of hepatocytes, often due to alcohol


functions of the pancreas


1) exocrine secretion- secretion of pancreatic juice to aid in digestion 2) secretion of hormones to regulate blood sugar levels by way of Islets of Langerhans, hormones=insulin and glucagon


What are the 3 unpaired branches of abdominal aorta that supply blood to the digestive tract?


1) Celiac trunk 2) Superior mesenteric artery 3) Inferior mesenteric artery


What does the celiac trunk supply?


stomach, liver, gallbladder, pancreas, spleen, and part of the doudenum


What does the Superior Mesenteric artery supply?


most of the doudenum, jejunuem, ileum, cecum, appendix, ascending colon, and 1/2 of the transverse colon


What and where is the appendix?


tube connected to the cecum of the large intestine-has no real purpose