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ch 24 digestive syst
| Question | Answer |
|---|---|
| the digestive system has 2 groups of organs: | GI Tract (aka gatrointestinal tract and alimentary canal) and Accessory organs |
| a continuous tube that extends from the mouth to the anus | alimentary canal |
| in the ___ digestive organs, secretions aid chemical breakdown of food | accessory |
| functions of the GIT: | 1. ingestion 2. secretion 3. mixing and propulsion 4. digestion 5. absorption 6. defecation |
| accessory digestive organs | teeth (grinder), tongue (mixer), salivary glands, liver, gallbladder (storage), and pancreas (produce enzymes) |
| each day cells within the walls of the GIT and accessory digestive organs secrete __, ___, ___, and ___ into the lumen (interior space) of the tract; these aid in chemical breakdown of food | water, acid, buffers, and enzymes |
| ___ digestion includes mastication (teeth cut & GRIND food) and movements of GIT (smooth muscle of stomach and small intestines CHURN food) | mechanical |
| ___ digestion is a series of hydrolysis rx that break down large carbs, lipids, proteins, & nucleic acids in foods into smaller molecules that are usable by body cells | chemical |
| the four layers of the GIT, from deep to superficial: | mucosa, submucosa, muscularis, and serosa |
| 3 layers of the mucosa (inner lining) | epithelium, lamina propria, and muscularis mucosa |
| the protective, exocrine cells secreting mucus & fluid into lumen, & endocrine cells secreting hormones | epithelium |
| associated with the ___ ___ of the mucosa are extensive patches of lymphatic tissue (contains lymphatic nodules & CT) called MALT | lamina propria |
| a thin layer of smooth muscle fibers called the ___ ___ throws the mucus membrane of stomach and small intestine into many small folds, which increases surface area for digestion and absorption | muscularis mucosa |
| ___ consists of areolar CT that binds mucosa to muscularis | submucosa |
| the __ of the mouth, pharynx, parts of esophagus & anal sphincter contains SKELETAL muscle that produces voluntary swallowing (& voluntary control of defecation) & contains SMOOTH (involuntary) MUSCLE found in inner circular & outer longitudinal fibers | muscularis |
| superficial layer of serous membrane, aka visceral peritoneum because it forms part of the peritonuem; the esophagus lacks this | serosa |
| "brain of the gut"; consists of neurons arranged into the MYENTERIC plexus & SUBMUCOSAL plexus; intrinsic | Enteric Nervous System (ENS) |
| neurons of the myenteric plexus regulate GIT ___ | motility |
| neurons of the submucosal plexus regulate GIT ___ | secretions |
| the ___ plexus lies between smooth muscle layers of the muscularis | myenteric |
| the ___ plexus lies within the submucosa | submucosal |
| the plexuses of the ENS consists of ___ neurons, ___ and ___ neurons | motor neurons, interneurons, and sensory neurons |
| motor neurons of myenteric plexus controls GIT ___ while the motor neurons of submucosal plexus controls the ___ | motility; secretions |
| the sensory neurons of the ENS function as ___ and ___ ___ | chemoreceptors; stretch receptors |
| although neurons of the ENS can function independently they are subject to regulation by the neurons of the ___ | ANS |
| ___ fibers of the vagus nerves increase GIT secretion and motility by STIMULATING/increasing the activity of ENS neurons | parasympathetic |
| ___ fibers decrease GIT secretion and motility by INHIBITING ENS neurons | sympathetic |
| the largest serous membrane of the body; lines the wall of the abdominal cavity and covers some abdominal organs | Peritoneum |
| the peritoneum divided into the ___ and ___ peritoneum | Parietal and Visceral |
| the ___ peritoneum lines wall of abdominopelvic cavity | Parietal |
| the ___ peritoneum covers some of the organs in the cavity and is their serosa | Visceral |
| the space containing serous fluid that is between the parietal and visceral layers | parietal cavity |
| organs that lie on the posterior abdominal wall and are covered by peritoneum only on their anterior surfaces; they are not in the peritoneal cavity | retroperitoneal |
| retroperitoneal organs include: | kidneys, ascending & descending colons of large intestine, duodenum of small intestine, and pancreas |
| the peritoneum contains large ___ that weave between the ___ | folds, viscera |
| the folds bind the organs to one another and to the walls of the ___ cavity; also contain ___ vessels, ___ vessels, and ___ that supply the abdominal organs | abdominal, blood, lymphatic, nerves |
| the five major peritoneal folds | 1. greater omentum 2. falciform ligament 3. lesser omentum 4. mesentery 5. mesocolon |
| the largest peritoneal fold, drapes over the transverse colon and coils of the small intestine like a "fatty apron"; contains adipose and lymph nodes | greater omentum |
| attaches liver to the ANTERIOR abdominal wall and diaphragm | falciform ligament |
| an anterior fold in the serosa of the stomach and duodenum and suspends them from the liver | lesser omentum |
| fan-shaped fold of the peritoneum that binds the jejunum and ileum of the small intestine to the POSTERIOR abdominal wall; contains lymphatic vessels and lymph nodes | mesentery |
| 2 separate folds of the peritoneum bind the transverse colon and sigmoid colon of the large intestine to the POSTERIOR abdominal wall; contains lymphatic vessels and lymph nodes also | mesocolon |
| the mouth, aka oral cavity, formed by: | cheeks, hard & soft palates, and tongue |
| lips attached to gums by __ ___ | labial frenulum |
| space between lips and gums | vestibule |
| opening between the oral cavity and the oropharynx (throat) | fauces |
| anterior portion of the roof of the mouth | hard palate |
| posterior portion of the roof of the mouth | soft palate |
| hangs from free border of soft palate; drawn superiorly during swallowing to prevent swallowed foods from entering nasal cavity | uvula |
| the __ tonsils are between the arches, and the __ tonsils are at the base of the tongue | palatine, lingual |
| glands that releases a secretion called saliva that lubricates, dissolves, and begins the chemical breakdown of food | salivary glands |
| mucus membrane of mouth and tongue contains small salivary glands, all of which have a small contribution to saliva | minor salivary glands |
| the major salivary glands include: (and each gland is accompanied by a duct/s that open into the mouth) | parotid, submandibular, and sublingual |
| the ___ glands secrete a watery (serous) liguid containing salivary amylase (helps breakdown food) | parotid |
| because the ___ glands contains cells similar to parotid glands, plus some mucus cells, they secrete a fluid that contains amylase but is thickened with mucus | submandibular |
| the __ glands contain mostly mucus cells, so fluid is thicker and contributes only a small amount of salivary amylase | sublingual |
| salivation is controlled by the ___ ___ system | autonomic nervous |
| functions of saliva: | 1. saliva is 99.5% water, which helps dissolve foods 2. buffers acidic foods (by attaching/releasing H+) 3. Cl ions activate amylase, an enzyme that starts the breakdown of starch 4. mucus lubricates food (so it can be moved around easily) |
| ___ prevents attachment of microbes so they cannot penetrate the epithelium | Immunoglobulin A (IgA) |
| an accessory digestive organ composed of skeletal muscle covered with mucus membrane | tongue |
| each half of the tongue consists of an identical complement of ___ and ___ muscles | extrinsic and intrinsic |
| __ muscles move tongue side to side; move food to back of mouth for swallowing | extrinsic |
| ___ muscles alter the shape and size of tongue for speech and swallowing | intrinsic |
| the __ __ limits posterior movement of tongue | lingual frenulum |
| ___ on dorsal (upper) surface contain taste buds or sensory receptors for touch | papillae |
| ___ glands secrete both MUCUS and a watery serous fluid that contains the enzyme LINGUAL LIPASE (which breaks down triglycerides) | lingual glands |
| a typical tooth has 3 major external regions: | crown, neck, and root |
| the __ is covered by enamel (the hardest substance in the body) | crown |
| internally, the ___ forms the majority of the tooth; harder than bone | dentin |
| the dentin of the root is covered by ___, another bonelike substance, which attaches the root to the periodontal ligament | cementum |
| the dentin of a tooth encloses a space; the enlarged part of the space, the ___ ___, contains blood vessels, nerves and lymphatics | pulp cavity |
| humans have 2 sets of teeth (dentitions): | deciduous teeth, and permanent teeth |
| aka primary, milk or baby teeth; begins to erupt at about 6 months and about 2 teeth appear each month thereafter; 20 baby teeth total; all lost between 6 - 12 years of age | deciduous teeth |
| aka secondary teeth; erupt between 6 yrs - adulthood; 32 total | permanent teeth |
| chisel-shaped teeth; closest to midline; adapted for cutting into food; "central or lateral" based on position | Incisors |
| have a pointed surface used to tear and shred food; have only one root | cuspids (canines) |
| first and second premolars; crush and grind food | bicuspids |
| permanent molars which erupt as jaw grows to accommodate them | first, second and third (wisdom tooth) molars |
| ___ digestion in the mouth results from chewing (mastication)/grinding food and mixing with saliva to form a bolus (soft mass) | mechanical |
| 2 enzymes contribute to ___ digestion in the mouth: ___ amylase and ___ lipase | chemical; salivary; lingual |
| secreted by salivary glands; intiates breakdown of starch into smaller molecules | salivary amylase |
| secreted by lingual glands in tongue; becomes activated in acidic environment of stomach & works after food is swallowed; breaks down triglycerides into fatty acids and diglycerides | lingual lipase |
| a funnel-shaped, muscular tube that propels food; extends from the internal nares to the esophagus posteriorly and to the larynx anteriorly | pharynx |
| a collapsible, muscular tube that lies posterior to the trachea; extends from the inferior end of pharynx to the stomach; secretes mucus & transports food to stomach | esophagus |
| ___ regulates movement of food from pharynx into esophagus | upper esophageal sphincter (UES) |
| ___ regulates movement of food from esophagus into stomach | lower esophageal sphincter (LES) |
| esophagus has 4 layers | mucosa (contains mucus glands), submucosa, muscularis, and adventitia (outer layer that attaches esophagus to surrounding structures) |
| the movement of food from the mouth into the stomach is achieved by the act of swallowing, or | deglutition |
| swallowing occurs in 3 stages: | 1. vol. stage where bolus is passed into orofnx 2. pharyngeal stage, invol. pass. of bolus thru FNX into esoph (epiglottis seals off larynx & uvula moves upward to close off nasofnx) 3. esophageal stage, invol. passage of bolus thru esoph. into stomach |
| in the ___, digestion of food continues, digestion of proteins & triglcyerides begins, bolus converted to a liquid, and certain substances are absorbed; serves as a mixing chamber and holding reservoir | stomach |
| the stomach has 4 main regions: | cardia, fundus, body, pylorus |
| surrounds the superior opening of the stomach | cardia |
| rounded portion superior to and to the left of the cardia | fundus |
| inferior to fundus is large central portion of stomach | body |
| region where stomach connects to duodenum | pylorus |
| the pylorus communicates with the duodenum of the small intestine via a smooth muscle sphincter called the: | pyloric sphincter |
| when the stomach is empty, the mucosa lies in large folds, called: | rugae (wrinkles) |
| the stomach wall is composed of same 4 basic layers as the rest of the GIT: | mucosa, submucosa, muscularis, serosa |
| the mucosa of stomach contains ___ glands | gastric |
| the gastric glands contain 3 types of EXOCRINE gland cells that secrete their products into the stomach lumen: | mucus neck cells (secrete mucus), CHIEF CELLS (secrete pepsinogen & gastric lipase), and PARIETAL CELLS [produce intrinsic factor (needed for absorption of vitamin B12) and hydrochloric acid] |
| the gastric glands contain a type of ENDOCRINE cell | G cells (secrete gastrin into bloodstream) |
| mechanical digestion in stomach starts several minutes after food enters the stomach when a gentle, rippling, peristaltic movement called ___ ___ pass over the stomach every 15-25 secs | Mixing Waves |
| these waves macerate food, mix it with secretions of the gastric glands, and reduce it to a soupy liquid called | Chyme |
| as food reaches the pylorus, each mixing wave forces chyme into duodenum thru the pyloric sphincter, this phenomenom is known as | gastric emptying |
| food may sit in stomach about an hour before ___ is produced by mixing with gastric juices | chyme |
| PARIETAL CELLS secrete H+ ions and Cl-, the net effect is secretion of ___; parietal cells also secrete ___ ___ (for B12 absorption) | HCI (hydrochloric acid), intrinsic factor |
| MUCUS CELLS secrete ___; this forms a protective barrier that prevents digestion of stomach wall; MUCUS CELLS are for absorption also | mucus |
| G CELLS secrete ___; stimulates parietal cells to secrete HCI and chief cells to secrete pepsinogen | gastrin |
| CHIEF CELLS secrete ___ and ___ ___ | pepsinogen (breaks down proteins) and gastric lipase (splits triglcyerides into fatty acids and monoglycerides) |
| why doesn't gastric juice digest the stomach? | lining of stomach is protected by an alkaline mucus barrier; pepsin is secreted in an inactive form called pepsinogen (which can't digest the proteins in the chief cells that produce it) |
| the ___ consists of a head, a body, and a tail; connected to the duodenum via the pancreatic duct and accessory duct; between stomach and duodenum; about 6 inches long | pancreas |
| the ___ duct unites with the common bile duct | pancreatic |
| the ___ duct empties into the duodenum | accessory |
| the pancreas is made up of small clusters of glandular cells. 99% of these clusters are called ___, the 1% is called ___ ___ (islets of langerhans) | acini, pancreatic islets |
| acini constitutes the ___ portion of the organ and secrete ___ | EXOCRINE, pancreatic juice |
| pancreatic juice forms the ___ portion of the pancreas and secretes ___,___,___,___ | ENDOCRINE, glucagon, insulin, somatostatin, and pancreatic polypeptide |
| pancreatic juice is a clear, colorless liquid consisting of: | mostly water, some salts, sodium bicarbonate, and several enzymes |
| ___ ___ buffers gastric juice in chyme, stops the pepsin from the stomach, and creates the proper pH for the action of digestive enzymes in the smal intestine | sodium bicarbonate |
| role of pancreatic enzymes in pancreatic juice: | digestion of proteins, triglyceride, starch, and nucleic acid |
| the starch digesting enzyme | pancreatic amylase |
| protein digesting enzymes (secreted in inactive form and produced in the stomach as pepsinogen) | trypsin, chymotrypsin, carboxypeptidase, and elastase are active forms |
| the triglyceride digesting enzyme | pancreatic lipase |
| teh nucleic acid digesting enzyme | ribonuclease nad deoxyribonuclease |
| pancreatic juice contains enzymes that digest starch (pancreatic amylase), proteins (trypsin, chymotrypsin, carboxypeptidase, & elastase), triglycerides (pancreatic lipase), and nucleic acid (ribonuclease & deoxyribonuclease) | |
| heaviest gland in the body weighing about 3 lbs; located inferior to the diaphragm | Liver |
| pear-shaped sac located in a depression of the posterior surface of the liver | gallbladder |
| liver has __ lobes | 2 lobes; a large RT lobe and a smaller LT lobe |
| liver divided into 2 lobes by the ___ ___, a fold of mesentary that extends from the undersurface of the diaphragm between the 2 lobes of the liver to the superior surface of the liver | falciform ligament |
| the parts of the gallblader include: | the body, neck and fundus |
| histological components of the liver: | hepatocytes, bile caniculi, and hepatic sinusoids |
| major functional cells of the liver and perform a wide variety of metabolic, secretory, and endocrine functions | hepatocytes |
| small ducts between liver cells that collect bile before it passes into bile ductules and hepatic ducts | bile canaliculi |
| bld caps btw rows of hepatocytes that rcv oxygtd blood from hepatic artery & nutrient rich de-oxygtd blood from hepatic portal vein | hepatic sinusoids |
| also has Kupffer cells that destroy worn-out wbc & rbcs, bacteria, & other foreign matter in the venous blood draining from the GIT | hepatic sinusoids |
| 3 different models for basic functional unit of liver | hepatic lobule, portal lobule, and hepatic acinus |
| shaped like a hexagon with the central vein at center | HEPATIC LOBULE |
| portal triad (bile duct, branch of the hepatic artery, and branch of the hepatic vein) at center | PORTAL LOBULE |
| preferred model in recent years; oval model between 2 neighboring lobules; LONG axis connects 2 central veins; portal triad located along the border of adjacent hepatic lobules | HEPATIC ACINUS |
| produce bile taht is carried by a duct system (series of canals) to the gallbladder for concentration and temporary storage | Hepatocytes |
| the ducts merge to form right and left hepatic ducts; these merge to form ___ hepatic duct; and then this unites with ___ ___ from gallbladder and merges with ___ ___ to duodenum | common, cystic duct, pancreatic duct |
| the liver receives blood from 2 sources | hepatic artery (oxygenated blood) and hepatic portal vein (deoxygenated blood) |
| map of blood supply of liver | portal triad (hep artery and hep portal vein) to central vein, to hep vein, to inferior vena cava and to right atrium |
| yellow, brown to green in color that is secreted by the liver; and is needed for the absorption of dietary fats | bile |
| bile contains | water, bile salts and pigments, cholesterol leithin, and several ions |
| principal bile pigment and plays role in breakdown of RBCs | bilirubin |
| bile's contribution to digestion is the ___ of dietary lipids | emulsification (the breakdown of large lipid globules into suspension of small lipid globules) |
| between meals, bile flows into ___ for storage b/c sphincter of hepatopancreatic ampulla closes off entrance to duodenum | gallbladder |
| functions of hepatocytes/liver: | 1. carbohydrate metabolism: release or storage of glucose 2. lipid metabolism: store triglyc, breakdown fatty acids to produce ATP, synthesize cholesterol 3. deaminate amino acids so that amino acids can be used for ATP production or converted to carbs |
| functions of hepatocytes/liver cont.... | 4. convert ammonia to urea which is excreted in urine 5. synthesis of plasma proteins such as alpha & beta globulins, albumin, prothrombin, and fibrinogen 6. destroy worn out RBCs 7. excretion of bilirubin |
| functions of hepatocytes/liver cont... | 7. synthesis of bile salts 8. storgae of glycogen, vitamins (A,B12,D,E,K) and minerals (Fe, copper) 9. phagocytosis of bacteria and worn out cells 10. activation of vitamin D in skin, liver, and kidneys |
| major site of digestion and absorption of nutrients; consist of duodenum, jejunum, ileum; is 10 feet long | small intestine |
| small intestine contains ___ ___ that increase surface area for absorption (villi and ___ increase surface area for absorption as well_ | circular folds; microvilli (contains brush-border enzymes) |
| 3 regions of the small intestine include | duodenum (empties stomach, shortest), jejunum, ileum (joins large intestine, longest) |
| 4 layers of small intestine | mucosa, submucosa, muscularis, serosa |
| cells found in the epithelium layer of mucosa of small intestine | absorptive cells, goblet cells (secretes mucus), paneth cells (secrete lysozyme and are capable of phagocytosis) and enteroendocrine cells (secretes hormones) |
| the lamina propria of mucosa in small intestine contains | MALT |
| the submucosa of duodenum contains ___ ___ - an alkaline mucus that helps neutralize gastric acid | mucus glands |
| the ___ of the small intestine consists of 2 layers: an ___ thinner layer of longitudinal smooth muscle fibers, and an ___ thicker layer of circular fibers | musculars, outer, inner |
| the layer that completely surrounds the small intestine | serosa |
| contains water and mucus, about 1-2 liters produced per day; combines with ___ ___ to aid the absorption of substances from chyme in the small intestine | intestinal juice, pancreatic juice |
| digestive enzymes in plasma membrane of microvilli | brush border enzymes |
| brush border enzymes have carb-digesting enzymes called | alpha dextrinase, lactase, maltase, sucrase |
| brush border enzymes also have protein-digesting enzymes called | aminopeptidases and dipeptidases |
| brush border enzymes also have nucleotide-digesting enzymes called | nucleosidases and phophatases |
| mechanical digestion in small intestine consists of 2 types of movements | segmentations and peristalsis |
| refers to localized, mixing contractions that occur in portions of intestine distended by a large volume of chyme; mixes chyme with digestive juices & bring into contact w/ mucosa for absorption | segmentations |
| after segmentations stops, ___ ( migrating motility complex) begins; chyme is pushed forward; begins in lower portion of stomach and takes about 3 hours to reach end of ileum | peristalsis |
| in the mouth, ___ ___ converts starch (polysaccharide) to maltose (a disaccharide) | salivary amylase |
| in th stomach, ___ converts proteins to peptides, and lingual & gastric lipases convert some triglcy into fatty acids, diglcy, and monoglyc. | pepsin |
| the completion of the digestion of ___, __, and __ is a collective effort of pancreatic juice, bile, and intestinal juice in small intestine | carbs, proteins, and lipids |
| chemical digestion of carbs are from | pancreatic amylase and brush border enzymes |
| brush border enzymes digest the disaccharides into monosaccharides: | alpha dextrinase splits starch into glucose; sucrase splits sucrose into glucose & fructose; lactase splits lactose into glucose and galactose; maltase splits maltose into glucose |
| digestion of carbs ends when monosaccharides are produced, *** only monosaccharides can be absorbed **** | |
| protein digestion starts in stomach. Protein digestion is completed by 2 peptidases in the brush border: | aminopeptidase produce amino acids & peptides; dipeptidases produce amino acids |
| most lipid digestion occurs in small intestine thru action of | pancreatic lipase & emulsification from bile salts |
| a process where a large lipid globule is broken down into severl small lipid globules | emulsification |
| digestion of nucleic acids in small intestine from | pancreatic juice and brush border enzymes (called nucleosidases and phosphastases produce nitrogenous bases, pentoses, and phosphates) |
| the following can be passed /absorbed thru the epithelial cells of small intestine | 1. monosaccharides from carbs 2. single amino acids, dipeptides and tripeptides from PRoteins 3. fatty acids, glycerol & monglycerides from TRiglycerides 4. nucleotides from Nucleic Acids |
| absorption of lipids cycle: short chain fatty acids diffuse to blood cap; long chain fatty acids & monoglcy combine w/ bile salts to form MICELLES which ferry them into intestinal cells | inside cells, they recombine to form triglyc, form globules, and become coated with protein (now called chylomicrons), chylomicrons enter lateals (as opposed to blood caps where monosacc, AA, di & tripeptides & short chain FA are absorbed) |
| cycle of bile salt secretion by hepatocytes into bile, reabsorption by the ileum, and resecretion into bile is called | enterohepatic circulation |
| most bile salts reabsorbed by active transport in ileum and returned by blood to liver thru the ___ portal system for recycling | hepatic |
| delivers pancreatic juice into the duodenum via the pancratic duct | pancreas |
| produces bile (bile salts) necessary for emulsification and absorption of lipids | liver |
| stores, concentrates, and delivers bile into the duodenum via the common bile duct | gallbladder |
| major site of digestion and absorption of nutrients and water in the GIT | small intestine |
| secretion of intestinal juice in | mucosa/submucosa of intestinal glands |
| microscopic projections that contain brush border enzymes and that increase surface area for digestion and absorption | microvilli |
| fingerlike projections of mucosa that are sites of absorption of digested food and increase surface area for digestion and absorption | villi |
| folds of mucosa and submucosa that increase surface area for digestion and absorption | circular folds |
| consists of alternating cx of circular smooth muscle fibers that produce ___ and resegmentation of section of small intestine; mixes chyme with digestive juices & brings food into contact with mucosa for absorption | segmentation |
| type of peristalsis consisting of waves of cx and rlx of circular & longitudinal smooth muscle fibers passing the length of small intestine; pushes chyme toward ileocecal sphincter | migrating motility complex (MMC) |
| functions of large intestine | 1. completion of absorption 2. production of certain vitamins 3. formation of feces 4. elimination of feces |
| large intestine extends from ___ to ___ | ileum to anus |
| the four regions of large intestine are | cecum, colon, rectum, anus |
| starts at opening from ileum into large intestine called the | ileocecal sphincter/valve |
| after ileocecal valve is cecum, then ascending colon, transverse colon, descending colon, | sigmoid colon, rectum, then anus |
| large intestine has 4 layers (same as rest of GIT) | mucos, submucosa, muscularis, serosa |
| longitudinal bands of smooth muscle that gather large intestine into pouches | teniae coli |
| a series of pouches which give the colon a puckered appearance | haustra |
| mechanical digestion in large intestine includes | haustral churning - when distended contents are squeezed to next haustra, peristalsis - pushes contents down tract, and finally Mass Peristalsis - strong peristaltic wave that quickly pushes contents into rectum |
| what is the function of goblet cells in large intestine? | mucus production |
| what is function of absorptive cells in large intestine? | water absorption |
| chemical digestion in large intestine achieved by the action of ___ | bacteria |
| bacteria ferments any remaining carbs and releases these gases | H+, CO2, and methane |
| bacteria converts any remaining amino acids into simpler substances like | indole, skatole, and H2S |
| bacteria also decompose biliruben into | stercobilin |
| bacteria synthesizes some vitamins like | some V vitamins and vitamin K |
| by the time chyme has remained in large intestine 3-10 hours, it has become solid or semisolid because of water absorption and is now called | feces |
| 90% of water absorption occurs in | samll intestine |
| distention of rectal wall stimulate stretch receptors which initiates a ___ ___ that empties the rectum | defecation reflex |
| ___ anal sphincter under voluntary control | external |
| digestive activities occur in 3 overlapping phases | cephalic, gastric and intestinal phases |
| sight, smell, thought, or initial taste of food activates neural centers that tell salivary glands to secrete saliva and gastric glands to secrete gastric juice | cephalic phase of digestion |
| with the __ regulation of gastric phase stretch receptors result in nerve impulses that causes increased flow of gastric juice and peristalsis | neural |
| with the ___ regulation gastrin is released from Gcells causing increased secretion of gastric juice | hormonal |
| during the __ phase, the exit of chyme from stomach to small intestine slows down due to decrease of gastric motility and decrease of gastric secretion | intestinal |
| __ regulation decreases gastric motility in re to stretch of duodenum (enterogastric reflex) and ___ regulation is mediated by 2 major hormones, CCK (slows gastric emptying) and SECRETIN (buffers acid) | neural, hormonal |
| the end products of chemical digestion of: | carbs are monosaccharides; proteins are amino acids; lipids are monoglycerides and FA; nucleic acids are pentoses, P, and nitrogenous bases |
| the mechanisms of absorption of materials in the small intestine are | diffusion, facilitated diffusion, osmosis, and active transport |
| The soft palate, uvula, and epiglottis prevent swallowed foods/liquids from entering the respiratory passageways. | TRUE |
| The coordinated cx and rlx of the muscularis, which propels materials thru the GIT, is known as peristalsis. | TRUE |
| splitting food molecules into simple substances by hydrolysis with the assistance of digstive enzymes | chemical digestion |
| taking foods and liquids into mouth | ingestion |
| movement of food thru GIT due to smooth muscle cx | propulsion |
| passage inot blood or lymph of ions, fluids and small molecules via the epithelial lining of the GIT lumen | absorption |
| the following are true of the peritoneum: | the kidneys & pancreas are retroperitoneal; the greater omentum is the largest of the peritoneal folds; the falciform ligament attaches the liver to the anterior abdomenal wall & jejunum; the mesentery is assct with the jejunum & ileum |
| when a surgeon makes an incision in the small intestine, the doc will encounter structures in this order: | serosa, muscularis,muscularis mucosae, lamina propria, epithelium |
| the following are functions of liver: | carb, lipid and protein metabolism; excretion of bilirubin; synthesis of bile salts; activation of vitamin D |
| the following statements are true of gastric motility and secretion: | the sight, smell taste or thought of food can intitiate the cephalic phase of gastric activity; once activated stretch receptors & chemoreceptors in stomach trigger flow of gastric juice & peristalsis; intestinal phase reflex inhibits gastric activity |
| the following statements are true: | the MMC is a type of peristalsis in the SI; the large surface ara for absorption in the SI is due to the presence of circular folds, villi, microvilli; most long chain FA & monoglyceride absorption in the SI requires the presence of bile salts |
| the release of feces is dependent on: | stetching of the rectal walls an voluntary rlx of the external anal sphincter |
| the following is true concerning the liver: | as blood passes thru the sinusoids it is processed by hepatocytes & phagocytes; processed blood rtns from the liver thru the hepatic vein; liver rcv oxygenated blood thru hepatic artery; hepatic portal vein delivers deoxygenated blood from GIT to liver |
| collapsed, muscular tube involved in deglutition and perstalsis | esophagus |
| coiled tube attched to cecum | appendix |
| contains duodenal glands in the submucosa | duodenum |
| produces and secretes bile | liver |
| contains aggregated lymphatic follicles in the submucosa | ileum |
| responsible for ingestion, mastication, and deglutition | mouth |
| responsible for churnign, persistalsis, storage, and chemical digstion with the enzyme pepsin | stomach |
| storage area for bile | gallbladder |
| contain acini that release juices containing several digestive enzymes for protein, carb, lipid, & nucleic acid digestion & sodium bicarb to buffer stomach acid | pancreas |
| composed of enamel, dentin, and pulp cavity; used in mastication | teeth |
| passageway for food fluid and air; involved in deglutition | pharynx |
| forms a semisolid waste material thru haustral churning and perstalsis | colon |
| forces the food to the back of mouth for swallowing; places food in contact with teeth | tongue |
| produce a fluid in mouth that helps cleanse the mouth and teeth and that lubricates, dissolves, and begins the chemical breakdown of food | salivary glands |
| an enzyme that initiates carb digestion in the mouth | salivary amylase |
| principal triglyceride digesting enzyme in adults | pancreatic lipase |
| secreted by glands in the tongue; begins breakdown of triglycerides in the stomach | lingual lipase |
| a nonenzymatic fat-emulsifying agent | bile |
| microvilli of the SI that increase surface area for absorption; also contain some digestive enzymes | brush border |
| fingerlike projections of the mucosa of the SI that increase surface area for digestion and absorption | villi |
| produce HCI and intrinsic factor in the stomach | parietal cells |
| secrete lysozyme; help regulate microbial population in the intestines | paneth cells |
| stomach enteroendocrine cells that secrete gastrin | G cells |
| longitudinal muscular bands in the LI; tonic cx produce haustra | teniae coli |
| lymphatic cap used for chylomicron absorption in the SI | lacteal |
| controls GIT motility and secretions of GIT orgains | ENS |
| large mucosal folds in the stomach | rugae |
| secrete pepsinogen & gastric lipase in the stomach | chief cells |
| permanent ridges in the mucosa of the SI; enhance absorption by increasing surface area and causing chyme to spiral rather than move in a straight line | circular folds |
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