Question | Answer |
What are the 7 main parts of GI tract? | Mouth, pharynx esophagus, stomach, small intestines, large intestines, and anal canal |
What are the accessory digestive organs? | teeth, tongue, gallbladder, salivary glands, pancreas, liver |
what are the 6 basic activities of the GI tract? | Ingestion, propulsion, mechanical digestion, chemical digestion, absorption/secretion, defecation |
How is food moved through the GI tract? | Perostalsis |
What is similar about the GI tract from the esophagus to the anal canal? | Has the same basic arrangements of tissues |
What are the four basic layers of the tract from the inside out? | Mucosa, submucosa, Muscularis, serosa |
What are the three layers of the mucosa? | epithelium, lamina propria, muscularis mucosa |
What is the function of the epithelium in the mucosa? | protection, secretion & absorption |
What is the function of the lamina propia layer in the mucosa? | (connective tissue) blood and lymphatic vessels for nutrient absorption |
What is the function of the muscularis mucosa of the mucosa? | (smooth muscle fibers) create small folds to increase surface area |
What is the purpose of the submucosa? | (connective tissue) sits between two layers of muscle-binds the mucosa to the muscularis |
What contains the submucosal nerve plexus? | submucosa |
What does the submucosal nerve plexus serve? | muscularis mucosa and controls secretions by the GI tract |
Which part of the digestive system requires some voluntary control? | Mouth, pharynx and upper esophagus and external anal sphincter-part skeletal muscle for voluntary swallowing and defecation |
What kind of muscle does the GI tract have? | 2 layers of smooth muscle:circular & longitudinal |
What is the exception regarding the muscle in the GI tract? | The stomach has 3 layers of muscle where as the rest has 2 layers |
What is the myenteric plexus? | nervous supply to muscle |
Similar to the heart and lungs, what might we call the tissue that covers the surface of GI tract organs? | Serosa |
What kind of tissue does the serosa include? | connective and epithelium |
What are the layers of the peritoneum and where do you find them? | visceral & parietal |
what is the definition of retroperitoneal cavity? | Is the anatomical space in the abdominal cavity behind the peritoneum. |
What are some examples of organs that lie on the posterior wall and are only covered on their anterior surfaces? | most of pancreas, and parts of the large intestines |
What is a retroperitoneal organ? | An organ that lies posterior to the peritoneum |
What is a mesentery? | a double layer of peritoneum-a sheet of two serous membranes fused back to back |
Where is the greater omentum located? | hangs over the transverse colon like a vascular apron |
What is a function of the omentum? | protection, insulation |
what does the mesentary do? | binds small intestines to the abdominal wall |
what does the mesocolon do? | binds large intestines to posterior body wall |
what does the lesser omentum do? | binds lesser curvature of the stomach to the liver |
what is a complication of cirrhosis of the liver? | encephalopathy, ascites(exess of fluid in the space between membranes lining the abdomen and abdominal organs) |
which part of the digestive tract have 3 layers of muscle in their muscularis tissue layer? | stomach |
Which layer of the digestive tract is made up of mostly connective tissue and sits between two layers of muscle? | submucosa |
How long is the esophogus? | 10in long |
what is the spincter called that is the entrance of the esophagus? | esophageal sphincter |
what event coincides with the relaxation of the esophageal sphincter? | swallowing |
Where does the esophagus enter the peritoneal cavity? | at the esophageal hiatus |
what are the three muscle layers of the stomach? | outer longitudinal, middle circular, inner oblique layer |
What are the names of the parts of the stomach? | cardia, fundus, body, pyloric |
what is the pylorus? | gatekeeper of the stomach |
How does the stomach assist with digestion? | Mechanically:peristaltic mixing, churning and mixing
Chemically: adds chemicals to breakdown protein |
How much absorption happens in the stomach? | very little |
What is the first section of the small intestines/ | duodenum |
How do we describe the location of the duodenum? | retroperitoneal cavity |
What does the duodenum recieve from the stomach? | chyme |
What does the duodenum recieve through the hepatopancreatic ampulla? | Bile, pancreatic juice, enzymes |
Where does absorption take place? | in the jejunum of the small intestine |
How long is the jejunum? | 8ft |
How long is the ileum? | 12ft |
What is the longest and last section of the small intestines/ | ileum |
where is the ileocecal valve located? | point at which the ileum enters the cecum |
How do the contents of the digestive system change once in the large intestines and why? | Chyme converted to semisolid stool or feces, due to water absorption |
What is the cecum? | expanded pouch at the base of the ascending colon |
What accessory organ is attached to the cecum? | the vermiform APPENDIX |
What are the 4 parts to the colon? | ascending, transverse, descending and sigmoid |
The walls of the colon are formed by a series of what that allow for distention? | haustra |
Digestion in the G.I. tract depends on 3 accessory structures? | pancreas, liver and gallbladder |
Where does the majority of absorption of nutrients occur? | small intestines |
Where is the pancreas located? | in the retroperitoneal cavity-posterior and inferior to the stomach |
where does the pancreas empty? | the duodenum |
what are the two ducts of the pancreas that empty into the duodenum? | smaller accessory duct & the larger pancreatic duct(heptopancreatic ampulla) |
What does the pancreas secrete? | digestive enzymes and hormones(insulin) |
What are the 4 lobes of the liver? | right & left lobe-separated by falciform ligament, quadrate lobe and caudate lobe |
what separates the right and left lobe of the liver? | falciform ligament |
which two vessels bring blood to the liver? | hepatic artery and portal vein |
What type of blood does the hepatic artery carry? | oxygenated blood to the liver |
what type of blood does the portal vein carry? | nutrient rich blood to the liver |
Portal vein to where? | to liver |
Splenic from where? | spleen |
Veins carrying products of digestion do not directly enter the systemic circulation instead they are delivered to where? | to the liver via the portal vien |
What does the liver do? | metabolizes nutrients from GI, detoxification, bile production & secretiion, storage of glycagon + some vitamins and minerals |
Where is the bile produced and excreted? | the liver |
What does the gallbladder do? | stores and concentrates bile up to 10 fold until it is needed in the small intestines |
Smooth muscle in wall of gallbladder contract causing what to happen? | bile forced into cystic duct, bile duct and than small intestine |
what is bile used for? | digestion of fat |
where does the gallbladder force bile into? | the cystic duct, the bile duct, small intestines |
intrinsic muscles do what to the tongue? | change the shape |
extrinsic muscles do what to the tongue | alter the tongues position |
what is the lingual frenulum? | attachment to the floor of the mouth=tongue tied |
which taste buds are the only ones you can see? | circumvallate papilla |
which salivary gland does the mumps effect? | parotid |
what is saliva secreted from? | serous and mucous cells |
what is the main component of saliva? | water |
how much water makes up saliva? | 97-99.5% |
what electrolytes are found in saliva? | na+, k+, cl-,po4 2-, hco3-(bicarbonate) |
what is the enzyme that starts digesting starch in the mouth? | salivary amylase |
what is the enzyme that starts digesting fat in the mouth? | lingual lypase |
what wraps the bolus so it can slide down the throat>? | mucin |
what metabolic wastes are found in the saliva? | urea, and uric acid |
what is found in saliva that helps protect against microorganisms? | lysozyme, IgA, defensins and a cyanide compound |
What does peridontitis effect? | the tooth ligament(periodontal) |
what is the gingiva? | gum |
how many primary teeth do we have? | 20 |
how many permanent teeth> | 32 |
why doesnt enamel grow back? | because its avascular |
what makes up the majority of the tooth? | dentin |
where are the blood vessels and nerves found in the tooth? | in the pulp |
what does the periodontal ligament adhere to? | the cementum |
what does occlusion mean? | How teeth fit together |
where does the start of digestion occur? | in the mouth with mastification(chewing) |
what begins the breakdown of disaccharides(sugars) in the mouth? | salivary amylase |
what do liver lobules do? | filter and process nutrient-rich blood |
What is at each corner of the liver lobule? | bile duct(recieves bile from bile canaliculi)portal arteriole(branch of the hepatic artery)Hepatic venule(a branch of the hapatic portal vein) |
what are liver sinusoids? | leaky capillaries between hepatic plates |
what are kupffer cells | hepatic macrophages |
where does the blood enter the liver> | the portal vein |
what is entering the liver through the portal vein? | blood from entire GI tract |
what are the functions of the hepatocyte? | process bloodborne nutrients, store fat-soluble vitamins, perform detoxification, and produce 900 ml of bile per day |
what is a yellow-green *alkaline* solution called? | bile |
what does bile contain? | bile salts, bilirubin,cholesterol, neutral fats, phospholipids and electrolytes |
what are bile salts? | cholesterol derivative that function in fat emulsification and absorption |
what is bilirubin? | pigment formed from heme |
what is the enterohepatic circulation> | recycles bile salts |
what is the circulation route of bile through the enterohepatic circulation> | bile salts-duodenum-reabsorbed from ileum-hepatic portal blood-liver-secreted into bile |
the gallbladder stores and concentrates bile by doing what? | by absorbing its water and ions |
the gallbladder releases bile via what? | the cystic duct |
where does the cystic duct flow into> | the bile duct |
the liver is a what kind of system>? | low pressure |
how prevalent is Hep C? | 1.8% of US population |
what is the largest source of people with Hep C infection? | injecting drug us 60% |
what is compensated liver disease? | the body is coping(compensating) well enough to function and stay alive..with the disease |
what is decompensated liver disease? | the body can no longer cope with the disease and is failing to survive |
what is varices? | esophogas vericose veins |
the hepatic vein takes filtered blood to where? | the heart |
Hepatic vein obstruction leads to what>? | ascites |
what are the symptoms of ascites? | coughing, tiredness, pulmonary edema(excess fluid in the lungs)pumping action of the heart grows weaker, pleural effusion(excess fluid around the lungs) swelling in abdomen, swelling in ankles and legs |
what is the earliest sign of ascites? | swelling of abdomen |
what is the best way to detect ascites? | ultrasound |
what is hepatic encephalopathy> | It is characterized by various neurologic symptoms including changes in reflexes, changes in consciousness, memory loss, confusion..coma |
what is one of the causes of hepatic encephalopathy? | failure to metabolize amonia |
what are some causes of a peptic ulcer? | high acid and peptic content, irritation, poor blood supply, poor secretion of mucus, H. Pylori infection |
where in the stomach are peptic ulcer more likely to be | down by the pyloric area or cardia area |
Most ulcers are caused by what? | infection, not spicy food |
what is the most common ulcer symptom> | burning pain in stomach |
can ulcers be cured for good? | yes, because of antibiotics for H. Pylori |
where are the H pylori bacteria found in the stomach? | mucosa layer |
Metastasized colon cancers frequently cause what? | secondary liver cancer |
90% of colon cancers are found at what age? | past age 50 |
mastication is partly voluntary and partly what? | reflexive |
What enzymes aid in chemical digestion in the mouth? | lipase, amylase |
what is deglutition? | swallowing |
What two things rise in order to prevent food from entering the respiratory passageway? | uvula and larynx |
what sphincter relaxes to allow food to enter the esophagus? | the esophageal sphincter |
food is moved through the esophagus to the stomach by what? | peristalsis |
where does the involuntary phase begin in swallowing? | when the food bolus is forced into the oropharynx |
what sphincter must open in order to allow food into the stomach | the gasteroesophageal |
what does the lesser omentum connect? | liver to stomach |
where is the greater omentum located? | hangs from greater curvature of stomach and hangs over transverse section of large intestines |
what are the gastric glands | mucous neck cells, parietal cells, chief cells, enteroendocrine cells |
what do the mucous neck cells secrete? | thin, acidic mucus |
what do the parietal cells secrete? | stomach acid (HCL) |
what do the chief cells secrete | pepsin and gastric lipase |
protein digestion is initiated by what? | pepsin |
intrinsic factor is required for absorption of what? | vitamin B12 |
lack of intrinsic factor results in what/ | pernicious anemia |
what delivers chyme to the small intestine? | the stomach |
what produces most of the gastric juices in the stomach? | THE FUNDUS AND BODY |
WHAT DO PARIETAL CELLS SECRETE? | HCL(hydrochloric acid or gastic juice) and intrinsic factor |
what does HCL do> | denatures protein in food, activates pepsin and kills many bacteria |
what activates pepsin? | HCL |
pepsin works best in what kind of environment? | ACIDIC(LOW PH) |
what buffers gastric acid to prevent damage to the epithelium of the stomach? | bicarbonate |
What does intrinsic factor do? | complexes with vitamin b12 to permit absorption |
where do hormones go in the body? | everywhere |
which three chemicals stimulate parietal cells? | Ach, histamine, and gastrin |
Does hydrochloric acid directly function in digestion? | no, it kills microorganisms, lowers the stomach pH to between 1.5 and 2.5; and activates pepsinogen. Pepsinogen is an enzyme that starts protein digestion. Pepsinogen is produced in cells that line the gastric pits. It is activated by cleaving off a porti |
what inhibits gastric secretion and duodenal filling? | enterogastric reflex and enterogastrones |
which chyme moves quickly through the duodenum? | carbohydrate rich |
which chyme moves slowly through the duodenum? | fatty chyme |
where is chemical digestion completed? | in the small intestines |
where is the majority of water absorbed? | in the small intestines |
how long does food stay in the small intestines/ | 3-6 hours |
where is the small intestine located? | from the pyloric sphincter to the ileocecal valve |
which of the small intestines is largest? | ileum |
what do the circular folds(plicae circulares) do? | slows chyme down |
what are the simple columnar absorptive cells called>? | enterocytes |
where are peyers patches located? | in the submucosa of the small intestines |
what does the pancreas excrete? | insulin and glucagon |
what do acini in the pancreas secrete? | pancreatic juice |
what are acini cells? | clusters of secretory cells |
zymogen granules of secretory cells contain what>? | digestive enzymes |
where is the pancreas located> | mostly retroperitoneal |
Pancreatic juice is what type of solution? | watery alkaline(PH 8) that neutralizes chyme |
what type of electrolytes are in pancreatic juice? | primarily HCO3- |
What enzymes are in the pancreatic juice? | amylase, lipases, nucleases are secreted in active form but require ions or bile for optimal activity |
Proteases is secreted in the pancreatic juice in what form?? | inactive |
where is the proteases activated? | in the duodenum |
trypsinogen is activated to trypsin by what? | brush border enzyme enteropeptidase |
where is trypsinogen activated at? | in the pancreas |
what is trypsinogen activated into? | trypsin |
what are activated by trypsin? | procarboxypeptidase and chymotrypsinogen |
where is the pancreas located in the abdominal cavity? | upper left quadrant |
what stimulates the gallbladder to contract? | CCK from intestinal cells exposed to proteins and fat chyme |
what causes the hepatopancreatic sphincter to relax? | cck |
bile comes back through what? | the portal system |
bile secretion is stimulated by what? | bile salts in enterohepatic circulation &n secretion from intestinal cells exposed to HCL and fatty chyme |
cck induces the secretion of what? | enzyme rich pancreatic juice by acini |
secretin causes secretion of what/ | bicarbonate rich pancreatic juice by duct cells |
what three things do you need for chemical digestion-Hydrolysis to take place? | water, enzymes, energy nutrient |
carbohydrate gets converted into what? | glucose |
protein and fat get converted into what? | amino acids and fatty acids and glycerol |
what enzymes are involved in digestion of nucleic acids? | pancreatic ribonuclease and deoxyribonuclease |
How is nucleic acid absorbed? | through active transport |
where are nucleic acids transported to ? | the liver |
how are the nucleic acids transported to the liver? | via hepatic portal vein |
what are some causes of malabosorption of nutrients/ | anything that interferes with delivery of bile or pancreatic juice or damage to the intestinal mucosa(bacterial infection) |
what forces feces into the rectum | mass movement |
what initiates spinal defecation reflex? | distension |
what do parasympathetic signals do? | stimulate contraction of the sigmoid colon and rectum and relax the internal anal sphincter |
what allows relaxation of the external anal sphincter? | conscious control |
what is the largest gland in the body? | the liver |
the liver receives 80% of its blood from where? | the portal vein |
the liver recieves 20% of its blood from where? | from the heart via the hepatic artery and arterioles |