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92 Cards in this Set
- Front
- Back
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What's the study of the digestive system? |
Gastroenterology |
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4 stages of the digestive system |
1) ingestion 2) digestion 3) absorption 4) defecation |
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2 stages of digestion and what they do: |
1) mechanical: teeth grind food, stomach/intestines churn 2) chemical: enzymes break food from macromolecules into monomers |
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2 subdivisions of the digestive system and what comprises each: |
1) digestive tract (alimentary canal/GI tract) 2) accessory organs (teeth, salivary glands, tongue, liver, gallbladder, pancreas) |
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4 layers of GI tract from deep to superficial: |
1) mucosa 2) submucosa 3) muscularis externa 4) serosa/adventitia |
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What is the most extensive membrane of the digestive system? |
Peritoneum |
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What is the serous membrane that lines peritoneal cavity? What is inflammation of this cavity called? |
- peritoneum - peritonitis |
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What lining is continuous w/ the peritoneum and binds intestines from abdominal wall? |
Mesentery |
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What are the 2 divisions of the mesentery? |
Greater & lesser omentum |
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What is the "nervous system" of the digestive system? What does it control? |
-Enteric nervous system - motility & secretion |
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3 mechanisms of regulation in digestive system: |
1) autonomic regulation: swallowing, para stimulation of motility/secretion 2) hormonal (bloodstream) 3) paracrine (diffuse nearby) |
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What's continuous w/ the oral orifice? What's contained in the oral cavity for defense? 7 functions of oral cavity: |
- oropharynx - defensins - ingestion, taste, mastification, chem digestion, deglutition, speech, respiratory |
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3 features of the oral cavity: What's the vestibule? Labial frenulum? |
1) cheeks/lips 2) tongue 3) hard/soft palate - Vestibule is space b/w teeth & cheeks - it attaches lips to the gums |
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What's the meeting of the teeth/mouth when shutting called? What's the difference between the pre molars & molars? |
- occlusion - pre molars: 2 cusps, molars: 4 cusps |
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When do baby teeth erupt? What are primary teeth? What's the alveolus of the tooth? |
- by 24 mo - deciduous/baby teeth - tooth socket |
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2 types of salivary glands: |
1) intrinsic 2) extrinsic |
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3 types of extrinsic salivary glands: How are the mumps contracted? |
1) parotid 2) sublingual 3) submandibular - via saliva |
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What do the serous cells of salivary glands secrete? What are compund glands? |
- thin, watery fluid containing amylase - glands w/ more than 1 cell type |
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What type of reaction is digestion? What makes fats different from carbs & proteins? |
- catabolic (large molecules into monomers) - they aren't multi unit molecules |
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What digestive layer forms sphincters? |
Muscularis externa |
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What are some of the functions of saliva? What kind of solution is saliva? What's its pH? How much is accumulated daily? |
- begin starch/fat digestion, inhibit bacteria, dissolve molecules, stimulate taste buds - hypotonic, 97% water - 6.8-7.0 - 1-1.5 L |
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In the saliva, what aids in swallowing? What antibody is present? What bacteria is present? Where is this bacteria commonly found?
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- mucin - IgA - lysozymes: in tears |
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What starts salivation and where is it started? What's the difference between sympathetic & parasympathetic salivary glands? What stimulates tactile, pressure, & taste receptors? |
- salivatory nuclei in medulla - sym are less abundant & produce thicker saliva, para produce thinner saliva - food |
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2 skeletal muscle layers of the pharynx: What are the 3 pharyngeal constrictors and what do they do? What does the inferior constrictor do when not swallowing? |
1) longitudinal (deep layer) 2) circular (superficial layer) - superior, middle, inferior: force food down in swallowing - remains contracted only allowing air in esophagus |
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What muscle tissue types comprise the upper & lower esophagus? What do the esophageal glands secrete? Where is the esophageal hiatus?
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- skeletal on upper, smooth on lower - mucus - diaphragm |
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Where is the cardiac orifice located? What does the inferior esophageal sphincter do? What is GERD? |
- stomach - closes cardiac orifice to reflux - gastroesophageal reflux (heartburn) |
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What is deglutition? 2 steps of deglutition: |
- swallowing 1) buccal phase 2) pharyngeal-esophageal phase |
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- Which swallowing phase is voluntary? What happens during this phase? - Which is involuntary? What happens? |
- buccal: pushes food into oropharynx & stimulates tactile receptors - pharyngeal-esophageal: pushes bolus down esophagus triggering peristalsis, lower esophageal sphincter relaxes |
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What's the vol of the stomach? How much is a typical meal? |
- 50 ml - 1-1.5 L |
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What is a muscular sac w/ 2 sphincters and is primarily used for food storage? |
Stomach |
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What is the main function of the stomach? What soupy mixture helps accomplish the function? |
- Mechanically break, liquify, & start chem digestion of proteins/fats - chyme |
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4 main regions of the stomach: |
1) cardiac 2) fundus 3) body 4) pyloric |
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What is the funnel like structure in stomach? What's the narrow passageway that ends at the pyloris? What controls chyme into duodenum? What are rugae? |
- antrum - pyloric canal - pyloris/pyloric sphincter - wrinkles |
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What structure is j shaped w/ greater & lesser curvatures? |
Stomach |
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2 main layers of stomach wall |
1) mucosa 2) muscularis externa |
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What 3 layers comprise muscularis externa of stomach wall? |
1) longitudinal 2) circular 3) oblique |
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What tissue lines gastric pits? What do the cells in the bottom of gastric pits do? |
- columnar epithelium - divide & move up to replace cells sloughed off into chyme |
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What are the 3 tubular glands in the gastric pits? In what region of the stomach are each found? |
1) cardiac glands (cardiac region) 2) pyloric glands (pyloric region) 3) gastric glands (everywhere else) |
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4 types of cells in gastric glands: What does each contain? |
1) mucous: mucus 2) parietal: HCl & intrinsic factor 3) chief: chymosin & lipase (for infant), pepsinogen (throughout life) 4) enteroendocrine: hormones & paracrine messengers |
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How much gastric juice is secreted daily? Which gastric cells secrete stomach acid? |
- 2-3L - parietal cells |
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4 functions of HCl: Which function is absorbed & utilized for Hb synthesis? |
1) activate pepsin & lingual lipase 2) break up connective tissue & plant cell walls (chyme) 3) convert Fe3+ to Fe 2+ (Hb synthesis) 4) destroy bacteria & pathogens |
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What does pepsin do? |
Digest proteins into peptides |
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- What's intrinsic factor essential for? What gastric cell secretes it? - What is pepsin derived from? What converts it? What gastric cell secretes it? - What does the chief cell also secrete? What is lipase? What does cymosin do? |
- B12 absorption into sm intes, RBC production; parietal cells - pepsinogen; HCl; chief cells - gastric lipase & chymosin; milk fat in infant; coagulates milk protein |
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- What signals the stomach to relax? - What does incoming food stretching the stomach activate? - What cells induce peristalsis? In which layer are they found? |
- swallowing center - receptive relaxation response - pacemaker cells: longitudinal muscle layer |
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How often does contraction occur during peristalsis? How long does it take a typical meal to move thru stomach? |
- every 20 sec - around 4 hrs |
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- What's emesis? What provokes this? - What does the emetic center do? Where's it located? - Where are the contents forced? |
- vomiting; emetics - causes lower esoph sphincter to relax, diaphragm/abdominal muscles contract (medulla) - up thru esophagus, sometimes into sm intestine |
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What 3 factors protect stomach from self digestion? How do they protect? |
1) mucous coat: highly alkaline mucus resists acid/enzymes 2) epithelial cell replacement: replaced every 3-6 days 3) tight junctions: no gastric juice seeps between epith cells |
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What are 3 accessory organs? What do they do? |
1) liver 2) gallbladder 3) pancreas - release secretions into sm intest to continue digestion |
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4 lobes of liver: What separates L/R lobes? What's the round ligament? Where's the gallbladder located? |
1) right lobe 2) left lobe 3) quadrate lobe 4) caudate lobe - falciform ligament - remnant of umbilical vein - on ventral surface b/w R & quadrate lobes |
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What blood vessel in liver receives blood from intestines? What's the Porta hepatis? What does the groove accomodate? What's the bare area of liver? What covers rest of liver? |
- hepatic portal vein - point of entry for hepatic artery & point of exit for bile/hepatic portal vein - inferior vena cava - diaphragm; serosa |
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-What cells comprise microscopic anatomy of liver? -What are tiny cylinders in liver? What do they contain? -Where does blood from the intestines go? -What are kupffer cells? What do they do?
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- hepatocytes
- hepatic lobules: central vein, sinusoids
- filtered by hepatocytes into central vein
- macrophages: remove bacteria & debris
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What 3 structures comprise the hepatic triad? What does each do?
What structures run b/w sheets of hepatocytes? |
1) hepatic portal vein: blood into liver 2) hepatic artery: blood into liver 3) bile duct: collects bile from bile canaliculi - bile canaliculi |
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Where do the ducts of the liver, gallbladder, & pancreas empty into? Where do they run? |
- Duodenum of sm intestine - from liver in common hepatic duct |
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What are the 4 ducts of the gallbladder, liver, & pancreas? Which is connected directly to gallbladder? |
1) cystic duct (connected to gallbladder) 2) common hepatic duct 3) bile duct 4) pancreatic duct |
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Which 2 ducts converge into bile duct? What do the pancreatic & bile duct converge into? How does it empty into duodenum? What does the hepatopancreatic sphincter do? |
- cystic & common hepatic
- hepatopancreatic ampulla; via major duodenal papilla
- regulates release of bile & pancreatic juice
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-What's contained in bile? -What is the pigment in bile? -What intestinal bacteria is in bile? Where is it found |
- minerals, bile acid, cholesterol, bile pigments, phospholipids - bilirubin from Hb - urobilinogen (urine) |
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What do bile acids (salts) & steroids (cholesterol) do? Where do they go for reuse? Via what? |
- emulsify/digest fats - liver via enterohepatic circulation |
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What 3 components comprise gallstones? Who are they commonly found in? What causes jaundice? |
- cholesterol, calcium carbonate, bilirubin - obese women over 40 due to high cholesterol - if bile gets into duodenum |
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-What type of gland is the pancreas?
-What are its 2 main functions?
-Where does the pancreatic duct open? What opens independently on duodenum?
- What is in pancreatic juice? |
- endocrine & exocrine gland
- 1) secrete insulin/glucagon into blood 2) secrete pancreatic juice into duodenum
- at the hepatopancreatic sphincter: accessory duct
- water, enzymes, zymogens, NaOH |
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What pancreatic enzymes aid in protein digestion? What digests DNA & RNA? |
- zymogens, trypsin, chymotrypsin, carboxypeptidase
- ribonuclease & deoxyribonuclease |
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What 3 hormones control secretion? Where is each located? |
1) cholestcystokinin (duodenum) 2) secretin (duodenum) 3) gastrin (stomach/duodenum) |
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-Which secretion hormone acts in response to acid & fat? What does it cause to happen? -Which hormone acts in response to acidic cyme? What does it cause to happen? -Which weakly stimulates gallbladder contraction & pancreatic enzyme secretion? |
- cholestcystokinin: gallbladder contract, pancreatic enzyme secrete, hepatopancreatic sphincter relax - secretin: stimulates all ducts to secrete bicarbonate - gastrin |
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What systems control digestion? |
Nervous & endocrine |
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3 main parts of sm intestine: Where are they located? How long are they? How long is the sm intestine? |
1) duodenum (10"): at end of stomach, beginning of sm intestine 2) jejunum (8'): upper abdomen 3) illeum (12'): lower abdomen - 20ft |
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Where does the illeum end? |
At the ileocecal junction w/ lg intestine |
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What are the 3 components of surface area in sm intestine? |
1) circular folds 2) villi 3) microvilli |
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What layers comprise the circular folds? What do the circular folds contain? What do they do with it? |
- mucosa & submucosa - chyme - spiral path increasing contact & nutrient absorption |
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-What type of action designates villi? -What 2 structures are contained in villi? What does each do? -What 2 cells cover the villi? |
- milking action
- 1) blood vessels: absorb nutrients 2) lymphatic capillary: absorb fat
- absorptive & goblet cells |
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What 3 functions do the microvilli serve? |
1) brush border on cells 2) brush border enzymes for final stages of digestion 3) contact digestion |
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What structures lead into intestinal crypts? What 3 types of cells are in the crypts? |
- pores b/w villi - absorptive cells, goblet cells, rapid dividing cells |
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-What 2 structures are in the intestinal crypts? What are their functions? Where are they located? |
1) Brunners glands (duodenum submucosa): secrete bicarbonate mucus to neut. stomach acid & protect mucosa
2) peyers patches (ileum): lymphocytes to fight pathogens |
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3 functions of intestinal motility/contraction: What does food in the stomach cause? |
1) mix chyme w/ intestinal juice, pancreatic juice, & bile 2) churn chyme 3) move residue to lg intestine
- gastroileal reflex (relax of ileocecal valve/filling of cecum) |
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How is contact w/ mucosa increased during contraction of sm intestine? How is food moved towards lg intestine? |
- random ringlike contractions/churning (segmentation) - successive overlapping of waves (migrating motor complex) or peristalsis |
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What's the purpose of segmentation as opposed to peristalsis? |
Segmentation is meant for mixing & churning, not for movement of materials as in peristalsis |
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2 main functions of sm intestine: What are brush border cells? |
1) chemical digestion 2) nutrient absorption - enzymes on cell membrane |
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-Where is the first destination for substances absorbed into blood? -What does the liver do for the blood? What does it store? |
- hepatic portal vein - detoxify: stores- vitamins/minerals, glucose, amino acids |
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Where does food spend the most time in the gut? How much? What is the s shaped portion of lg intestine? What is the straight portion ending at anal canal? |
- lg intestine (12-24 hrs) - sigmoid colon - rectum |
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What structures comprise the first part of the lg intestine? |
Cecum (pouch) & appendix |
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-What type of tissue comprises mucosa in lg intestine? Anal canal? -What do its intestinal crypts secrete? -What are the pouches & ribbon strips in the muscularis externa? -What tissue comprises the transverse & sigmoid regions? What's the rest? -What are epiploic appendages? |
- simple columnar; stratified squamous
- only mucus
- haustra (pouches), teniae coli (ribbons)
- serosa; retroperitoneal
- suspended fatty sacs |
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What's the difference between sm & lg intestines structurally? |
Sm intestine has villi & folds to increase SA, lg intestine doesn't have these |
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Where are bacterial flora present? What are they commonly called?
What % of feces is bacteria?
What 2 things do the bacterial flora do? |
- lg intestine (e coli)
- 30%
- 1) ferment cellulose & other undigested carbs/fats 2) synthesize vit B, vit K (absorbed by colon) |
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How much flatus do we excrete daily? What 2 amines are found in flatus? |
- 500 ml - indole & skatole |
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3 components of feces:
-How often do haustral contractions occur? What stimulates contraction?
-What triggers mass movements of feces? What are these reflexes called?
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- bacteria/mucus, fiber/fat, epith cells
- every 30 min; distension (fiber)
- filling of stomach & duodenum; gastrocolic & endocolic reflexes |
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What 2 structures comprise the anal canal? |
Anal columns & anal sinuses |
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What are the anal columns? What causes the anal sinuses to secrete mucus? What causes hemorrhoids? |
- longitudinal ridges separated by anal sinuses - when feces passes - distended hemorrhoidal veins |
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What causes defecation?
What are the 2 reflexes?
What causes abdominal contractions & lifts anal canal up? |
- stretching of rectum
1) intrinsic defecation 2) parasympathetic defecation - valsalva maneuver |
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What happens in intrinsic defecation? What 3 things happen in parasympathetic defecation? |
- muscularis contracts & internal sphincter relaxes; external anal sphincter voluntarily relaxes
- 1) stretching sends signal to spine 2) spine signal intensifies peristalsis 3) parasympathetic fibers relax internal anal sphincter |
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4 major health issues of digestive system: |
1) oral cancer (squamous cell mostly) 2) hiatal hernia (stomach/diaphragm) 3) peptic ulcers (H pylori caused by NSAIDs, GI bleed) 4) gastroenteritis (e coli, waste in water/food) |
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What is bariatrics? What's the difference between rous en Y bypass & vertical sleeve bypass? |
- study of treatment, prevention of obesity - in rous en the upper part of stomach is connected to jejunum; in vertical sleeve the stomach is cut in half |
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-What are the 6 unrelated viral infections of the liver? -Which are transmitted via food? -Which are transmitted via blood?Which is more common/more deadly? |
- hepatitis A-F - A & E - B & C - common= B, deadliest= C |
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Digestive Diseases: -Autoimmune condition of irritable bowel syndrome -Pockets in lg intestine (inflammation?) -Appendix inflammation -4th most common cancer |
- crohns disease - diverticulosis; diverticulitis (inflammation) - appendicitis - colorectal cancer |
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Eating Disorders: - self starvation - binge eating - obsession w/ diet, body form |
- anorexia - bulimia - muscle dysmorphia |
