Term
|
Definition
No VIP secretion for LES relaxation
Relaxation failure of the LES in response to swallowing due to vomiting and weight loss
No ganglion cells in the myenteric plexus of esophageal wall and LES |
|
|
Term
|
Definition
Food gets stuck because of lack of peristalsis, esophagus dilates, and patient regurgitates
Intermittint dysphagia during meals |
|
|
Term
| achlasia diagnosis methods |
|
Definition
Chest X-ray following barium swallow
Esophagoscopy to exclude milgnancy
Pneumatic bag is placed in LES opening to dilate it
Surgical division of LES in laproscopy
Manometry: evaluation of pressure |
|
|
Term
|
Definition
o LES pressure is often low
o Gastric pouch intra thoracic reservoir
o Diaphragm: no esophageal pinch |
|
|
Term
| leiomyoma: causes symptoms |
|
Definition
Most frequent benign tumor
Tumor of smooth muscle cells
No symptoms unless it ulcerates and bleeds |
|
|
Term
| carcinoma of the stomach: location, classification, risk factors |
|
Definition
Frequently in antrum
Almost always adenocarcinoma
Risk factors: H. pylori, chronic gastritis, atrophia, metaplasia, spicy, salted, smoked food with benzpyren, mitrosamines, blood group A |
|
|
Term
| enterchromaffin cells of the intestine wall carcnoid tumors: secrete, treatment, signs |
|
Definition
Carcnoid tumors that secrete serotonin, bradykinin, histamine, trachykinins, prostaglandins
Octerotide: somatostatin analogue that inhibits excess secretion
Signs: facial flushing, diarrhea |
|
|
Term
| acute GI bleeding: causes, dangers, how to diagnose, signs |
|
Definition
o Occurs in form of hematemesis (vomiting of blood)
o Causes: Peptic ulcer, esophageal varicose veins, gastric carcinoma, infection, polyp
o Dangers: Shock, tachycardia, decreased BP, pallor, Fe deficient anemia
o Examination: Gastroscopy, colonoscopy, enteroscopy |
|
|
Term
| coeliac disease: cause, location |
|
Definition
o Gluten sensitive enteropathy disease
o Duodenal and jejunal mucosa is destroyed via hypersensitivity to gluten |
|
|
Term
| appendicitis: cause, symptoms, treatment |
|
Definition
o Mechanical obstruction dilate until mucosa ulcerates and wall is invaded by bacteria
o Symptoms: Periumbilical or diffuse pain, Sub-febrile, Nausea, vomiting
o Appendectomy: Performed ASAP. Treated with antibiotics first so bacterial spread isn’t helped by surgery |
|
|
Term
| acute peritonitis: cause, symptoms |
|
Definition
o Cause: Perforation. Bacterial infection spreads. Hepatic, alcoholic cirrhosis with portal hypertension
o Symptoms: Sudden, severe pain, high fever, nausea, vomiting, paralytic ileus. Later: septic shock |
|
|
Term
| diverticulosis: defnition, cause, how to diagnose, symptoms, treatment |
|
Definition
o Herniation of mucosa through muscle layers of the colon usually in weak place in gut wall
o Cause: Increased intraluminal pressure. High incidence in inactive persons. Low incidence in vegetarians due to high fiber diet
o Diagnosis via Barium enema
o Symptoms: Disturbed stool habits
o Treatment: mild exercise |
|
|
Term
| colon cancer: cause, risk factors, prevention |
|
Definition
o Related to slow passage of feces with carcinogens that bind to DNA in it
o More frequent in sedentary persons with frequency of constipation
o Prevention: high fiber diet, daily walking |
|
|
Term
| dry mouth / eerostomia: causes |
|
Definition
• Lack functional salivary glands
• Infection of buccal mucosa
• Dental caries
• Dehydration
• antidepressants
• sjogern syndrome |
|
|
Term
| sjogern syndrome: cause, symptoms |
|
Definition
o Autoimmune disorder destroying exocrine glands
o Have dry mouth and dry eyes (xerophtalmia) and RA |
|
|
Term
| define digestion, what does it |
|
Definition
• Chemical breakdown of ingested food so it is absorbable
• Enzymes are secreted in salivary, gastric, and pancreatic juices |
|
|
Term
| define absorption: what are th two tyoes, explain them |
|
Definition
• Movement of nutrients, water, and electrolytes from lumen of intestine to blood
• Cellular: Substance crosses apical (luminal) membrane and is exits on basal into blood via transporters
• Paracellular: Substances move across tight junctions in intestinal epithelial cells and lateral intracellular spaces into blood |
|
|
Term
| what features of the mucosa allow for increased absorption |
|
Definition
o Longitudinal folds have villi for lots of absorption SA
o Villi are covered in epithelial cells (enterocytes) and mucous secreting cells (goblet cells) with microvilli on the surface (brush border)
o Villi are longest in duodenum
o Cells have high turnover rate. Very susceptible to irradiation and chemotherapy
o Plica circularis of kerckring: longitudinal folds in small intestines with villi (short in ileum) |
|
|
Term
where are most of the peyers patches at
where are brunner's glands at |
|
Definition
|
|
Term
| what modifies mucosal epithelium turn over, how does it turn over |
|
Definition
o has rapid turnover via apoptosis but it is modified by nutrients, especially fat
o come from stem cells at the case of crypt and migrate along crypt villus axis to intestinal lumen |
|
|
Term
| how are monosaccharudes digested, what are they |
|
Definition
Absorbed by intestinal epithelial cells
All ingested carbs must be turned into monosaccharides
Glucose, galactose, fructose |
|
|
Term
| what begins starch digestion, explain where this happens |
|
Definition
Salivary amalyase (a-amalyase)
• Begins digestion in mouth
• Inactivated by low pH of gastric contents |
|
|
Term
| how does the stomach contribute to carb digestion |
|
Definition
| pancreatic amalyase digests 1,4-glycocidic bonds making disaccharides (a-dextrinase, maltase, sucrose) |
|
|
Term
| some food is digested as a disaccharide and skips the steps in the stomach and mouth. what are these disaccharides, when and how are they broken down |
|
Definition
trehalase, lactase, and surcarse digest trehalose into 2 glucose, lactose into glucose and galactose, and surose into glucose and fructose.
the enzymes are brush border enzymes of the small intestines |
|
|
Term
| explain the absorption in the small intestines |
|
Definition
luminal side
• glucose and galactose. Na dependent co-transport (SLGT1) into cell against gradient. Energy comes from Na/K pump on apical side
•Fructose: Facilitated diffusion via GLUT5 transporter into cell. Cannot be absorbed against a gradient
Blood side
• Na/K ATPase: putting Na into blood
• Glucose, galactose, fructose: GLUT 2 transporters secondary active transport |
|
|
Term
| what is the main cause of disorders with carb absorption, what is a common example and its treatment |
|
Definition
o Mostly because carb was not broken down
o Large carbs in lumen hold in water causing diarrhea
o Lactose intolerance / hypolactasia: Lactase deficiency on brush border. Treatment: lactase supplement |
|
|
Term
| in what form do proteins need to be to be absorbed, what digests them in general |
|
Definition
AA, dipeptides, and tripeptides
proteases |
|
|
Term
| explain the cascade process of enzymes that digest proteins in the stomach and their conditions needed |
|
Definition
• pepsinogen is secreted by chief cells of stomach and activated to pepsin
• optimum pH 1-3, denatured at 5
• terminated in duodenum via bicarbonate
• not essential for protein digestion (pancreatic brush border enzymes can digest alone) |
|
|
Term
| explain the cascade of brush border endoepetidase enzymes that digest proteins in the small intestines |
|
Definition
trypsin:trypsinogen is turned into trypsin via enterokinase (a brush border enzyme). trypsin can activate more trypsinogen (autocatalyzation) or activate the other enzymes
chymotrypsin: trypsin turns chymptrypsinogen into chymotrypsin
elastase: trypsin turns proelastase into elastase |
|
|
Term
| explain the cascade of brush border enteropetidase enzymes that digest proteins in the small intestines |
|
Definition
Hydrolyze one AA at a time from C-terminal
carboxypeptidaseA: trypsin turns procarboxypeptidase A into carboxypeptidase
carboxypeptidase B: trypsin turns procarboxypeptidase B into carboxypeptidase |
|
|
Term
| why dont the enzymes of the brush border for proteins just keep digesting the body from the inside out |
|
Definition
| o after digesting proteins, the enzymes digest themselves and each other |
|
|
Term
| explain how L amino acids are absorbed |
|
Definition
Absorbed just like monosaccharides
Luminal side: 4 Na/AA co-transporters (neutral, acidic, basic, imino) on apical side energized by Na gradient via Na/K ATPase on basal side
Basal side: 4 transporters put them into blood via facilitated diffusion |
|
|
Term
| explain how tripeptides are absorbed |
|
Definition
Apical side: Separate H dependent co-transporters into IF. Gradient made by Na/H exchanger on apical side
Basal side: Most are hydrolyzed into AA by cytosolic peptidases and do facilitated diffusion to get out. The rest are absorbed unchanged |
|
|
Term
| what are some common protein digestion disorders. what are some common causes |
|
Definition
o Without gastric H+ secretion (no pepsin) protein digestion and absorption is normal showing pancreatic brush border enzymes can do it alone
o Deficiency of pancreatic enzymes or transporters
o Chronic pancreatitis and cystic fibrosis |
|
|
Term
| cystinuria: cause, effect |
|
Definition
Autosomal recessive
Transporter for dibasic AA cysteine, lysing, arginine, and ornithine missing in SI and kidney
Can’t absorb AA in intestines and excrete AA in urine
Makes stones in the kidney, ureters, and bladder |
|
|
Term
| what types of lipids are ingested, what are the differences in how they are absorbed |
|
Definition
• Triglycerides, cholesterol ester, phospholipids (all esterified)
• Monoclycerides, cholesterol, lysolecithin, and glycerol (water soluble) can be absorbed (de-esterified) |
|
|
Term
| how are lipids digested in the stomach, what hormones take part |
|
Definition
Churning: initiates breaking them into drops emulsifying, keep droplets apart
Lingual and gastric lipases: Hydrolyze 10% of TG to glycerol and FA
CCK: Slows gastric emptying so pancreatic enzymes have time to continue lipid digestion (more important) |
|
|
Term
| where is the area of most lipid digestion |
|
Definition
|
|
Term
| what is the function of bile salts, what other substance is usually with bile salts |
|
Definition
|
|
Term
| what are the pancreatic enzymes: are they active or inactive when secreted. what do they do |
|
Definition
• Pancreatic lipase: Secreted active. Hydrolyzes TG into monoglyceride and 2 FA. Inactivated by bile salts because they move enzyme from lipid-water interface, colipase solves this
• Cholesterol hydrolase: Secreted active. Hydrolyzes cholesterol ester to cholesterol and FA. Hydrolyzes ester linkages of TG making glycerol
• Phospholipase A2: Secreted as a proenzyme and activated by trypsin. Hydrolyzes phospholipids to lysolecithin and FA |
|
|
Term
| what are the pancreatic proteins: active or inactive when secreted, function |
|
Definition
| • Colipase: Secreted inactive as procolipase, activated by trypsin. Displaces bile salts from lipid-water interface. Binds to pancreatic lipase |
|
|
Term
| explaiin how lipids are absorbed |
|
Definition
o Lipids are solubized in micelles, except glycerol
o Micelles diffuse to brush border on intestinal epithelial cells (mostly mid jejunum) and release lipid
o Lipid moves down gradient
o Lipids are re-esterified inside cell SER
o Lipids are put in chylomicrons: TG and cholesterol in core. Phospholipid and apoproteins (made in epithelial cell) on outside. APO-B helps in re-absorption
o Golgi packages chylomicrons into secretory vesicles
o Exocytosis of vesicles to lacteals and to thoracic duct then blood |
|
|
Term
|
Definition
|
|
Term
| exocrine pancreas insufficiency: diseases, cause, effect |
|
Definition
Chronic pancreatitis, cystic fibrosis
Not enough pancreatic enzymes
Cannot absorb fat due to undigested TG |
|
|
Term
| duodenal acidity: issue, diseases |
|
Definition
Neutralizing doesn’t work
Pancreatic enzymes inactivated
Zollinger-Ellison syndrome
, pancreatitis |
|
|
Term
| zolliner ellison syndrome: cause, effect |
|
Definition
• Tumor causes lots of gastrin secretion
• Elevated H secretion by parietal cells |
|
|
Term
|
Definition
| • Impaired bicarbonate secretion |
|
|
Term
| deficiency of bile salts: cause, effect |
|
Definition
| ileal resection, cannot form micelles |
|
|
Term
| ileal resection: what is it, what does it break, how does this cause bad things |
|
Definition
• Removal of ileum
• Interrupts enterohepatic circulation of bile salts and they are excreted in feces
• New bile salts cannot keep up
• Bile acids are toxic to colonic mucosa and stimulate secretion of large volumes |
|
|
Term
| what does bacterial overbrowth do to lipid digestion |
|
Definition
Reduces effectiveness of bile salts by de-conjugating them (remove glycine and taurine converting them to bile acids)
Now lipid soluble they diffuse across epithelial cells before micelle formation and lipid absorption
Decreased pH deionizes too |
|
|
Term
| tropical spruse: what does it cause to happen |
|
Definition
| • Reduction in intestinal cells reduces SA allowing less lipid absorption |
|
|
Term
| abetalipoproteinemia: cause, effect |
|
Definition
• No APO B made
• Cannot absorb chylomicrons into lymph and thus lipids into the body |
|
|
Term
| what are the functions of vitamins in the body |
|
Definition
| • Co-enzymes or co-factors for metabolic reactions |
|
|
Term
| what are the fat soluble vitamins, how are they absorbed |
|
Definition
o ADEK
o Processed same as lipids |
|
|
Term
| what are the water soluble vitamins, how are they absorbed |
|
Definition
o B1, 2, 6, 12, C, biotin, folic acid, nicotinic acid, pantothenic acid
o Usually absorbed via Na dependent co-transporter in SI |
|
|
Term
| how is B12 released from food, how is it treanported |
|
Definition
B12 is released from food via pepsin . when free it binds to R proteins in salivary juices first
In duodenum proteases degrade R proteins and transfer B12 to intrinsic factor secreted by parietal cells
Intrinsic factor protects them from degradation |
|
|
Term
| gastrectomy: risks, treatment |
|
Definition
Loss of source of intrinsic factor
Cannot absorb B12
Pernicious anemia
Treatment: B12 supplement |
|
|
Term
| how is vitamin d activated |
|
Definition
• Activating vitamin D: Dietary vitamin D3 (cholecalciferol) > liver > 25-hydroxycholecalciferol > circulation PCT > 1,25-dihydroxycholecalciferol (via 1a-hydroxylase) (active form). Actions on intestine, kidney and bone.
• Calvindin D-28K: vitamin D-dependent Ca-binding protein . in intestinal epithelial cells |
|
|
Term
| what diseases are associated with vitamin D deficiency |
|
Definition
o decreased Ca
o rickets which can lead to osteomalacia |
|
|
Term
|
Definition
• absorbed on apical side as Fe or heme iron (Hb, myoglobin)
• heme iron is digested by lysosomal enzymes and released as Fe
• Fe binds to apoferritin and is transported to basolateral membrane
• Transferrin (B-globulin) binds Fe in blood and stores it in liver
• Transported to marrow for Hb synthesis |
|
|
Term
| hepcidin: where is it made, what does it do, what risks are associated with it |
|
Definition
o Fe homeostasis
o Peptide made in liver
o Regulate by inhibiting Fe transport across gut mucosa to prevent excess Fe absorption
o Inhibits transport of Fe out of macrophages where it is stored
o During inflammation it is too high and Fe can drop leading to anemia |
|
|
Term
| how much fluid is in the lumen, where did it come from |
|
Definition
• 9L of fluid in lumen
o 2L from diet
o 7L from secretions
o 100-200 mL not absorbed |
|
|
Term
| what type of fluid transport occurs in the small and large intestines, why is it different |
|
Definition
• Permeability of tight junctions determines fluid and electrolyte route (paracellular or cellular)
o Small intestine has leaky tight junctions
o Large intestines junctions are tight and don’t permit paracellular |
|
|
Term
what is the osmolality of intestinal fluid to plasma.
what is the fluid absorbed called |
|
Definition
|
|
Term
| jejunum: net absorption, luminal and blood pumps |
|
Definition
Net absorption NaHCO3
CO2 + H2O > H2CO3 > H+ + HCO3- via carbonic anhydrase
Luminal: Na / sugar or AA co transporter Na into cell. Na/H antiporter Na into cell
Blood: Na/K ATPase Na into blood. Monosaccharide or AA transporter into blood. Bicarbonate transporter into blood |
|
|
Term
| ileum: net absorption, luminal and blood pumps |
|
Definition
Net absorption NaCl
CO2 + H2O > H2CO3 > H+ + HCO3- via carbonic anhydrase
Luminal: Na / sugar or AA co-transporter into cell. Na/H antiporter Na into cell. Bicarbonate/Cl antiporter Cl into cell
Blood: Na/K ATPase Na into blood. Sugar or AA transporter into blood. Cl transporter into blood |
|
|
Term
| colon absorption pumps on lumen and blood side, how are they regulated |
|
Definition
Luminal
• Na channel into cell
o Increased synthesis via aldosterone
• K channel out of cell
o Aldosterone in effect increases K secretion
Blood
• Na/K ATPase Na into blood
• K channel into blood |
|
|
Term
| secretion in the colon occurs in what cells? what are their luminal and blood side channels and pumps |
|
Definition
Crypt cells
Luminal
• Cl channel into lumen
o Usually closed
o Opening: ACh, VIP
o Adenylyl cyclase > cAMP > opens Cl channel
Blood
• Na/K ATPase Na into blood
• Na/K/2Cl co-transporter into cell
• Water and Na go into lumen via junction
o Works more when Cl channel is open |
|
|
Term
| what are the risks of diarrhea, what processes occur, how does it affect the body |
|
Definition
High flow of intestinal fluid increases K secretion causes hypokalemia
Max loss is 9L of fluid a day
Decreased ECF, vascular volume, arterial pressure
Baroreceptors turn RAAS on but are futile
Loss of bicarbonate can cause hyperchloremic metabolic acidosis |
|
|
Term
|
Definition
• Decreased absorptive surface area, osmotic diarrhea, secretory diarrhea
• Cholera
• Ileal resection
• Zollinger Ellison syndrome |
|
|
Term
| what is the process of a cholea infection, explaiin how it leads to diarrhea |
|
Definition
1. Enters crypt cells
2. A subunit of toxin goes to basal membrane
3. Causes ADP ribosylation of a subunit of GTPase
4. GTP cannot convert back to GDP
4. Permanent action of adenylyl cyclase
5. Apical Cl channels open
6. Cl secretion pulls Na and water
7. Absorption cannot keep up
8. Severe poo |
|
|
Term
| what are the causes of decreased surface area for absorption in the colon |
|
Definition
Infection
Inflammation: caused by mucosal destruction with outflow of fluid and blood (like ulcerative colitis) |
|
|
Term
| what causes osmotic diarrhea, give an examile of a disease |
|
Definition
Presence of non-absorbable solutes in lumen causes water retention
Example: lactase deficiency, carbs not broken down |
|
|
Term
| explain why bacterial overgrowth causes diarrhea, which kind |
|
Definition
secretory diarrhea
Bacterial overgrowth (cholera, E. coli): enterotoxins affect toxin receptors to increase cAMP in cell, turning on Cl channels and inhibiting NaCl reabsorption |
|
|
Term
| explain the mechanism in secretory diarrhea |
|
Definition
Excessive secretion by crypt cells
Intestinal fluid secretion is isotonic with plasma even during fasting
Increased Cl secretion and decreased Na reabsorption |
|
|
Term
| what is exudative diarrhea, what can cause it |
|
Definition
Blood and pus in stool
Causes: E. coli, inflammatory bowel diseases, Chron’s Disease, ulcerative colitis |
|
|
Term
| what is chrons disease, how is it diagnosed |
|
Definition
o Chronic inflammatory bowel disease (IBD) where intestines are inflamed
o More frequent abdominal pain that perianal disease |
|
|
Term
| what is ulcerative colitis, how is it diagnosed |
|
Definition
o Chronic inflammatory bowel disease (IBD) where intestines are inflamed
o GI bleeding |
|
|
Term
| liver: location, fissures, surfaces, anatomical landmarks |
|
Definition
o RUQ and epigastric under ribs
o Diaphragmatic and visceral surfaces
o Fissure on visceral surface
o Porta hepatis: major vessels and nerves enter and leave
o Ligamentum teres: remnant of umbilical vein in fetus (attaches to navel) |
|
|
Term
| liver: cellular units, vessels, cells |
|
Definition
o Lobule: Hegaconal sheets of hepatocytes. Corners have portal triads (portal arteriole, portal venule, bile duct)
o Sinusoids: Large capillaries between hepatocytes that connect hepatic venis to IVC. Capillaries are in a portal system
o Kpuffer cells: Macrophages on the walls of sinusoids. Recycle blood, breakdown microbes
o Hepatocytes |
|
|
Term
| in the hepatocyte, explain what each organell is doing |
|
Definition
Many organelles
RER: manufactures blood proteins
SER: makes bile salts, detoxifies blood borne toxins
Peroxisomes: detoxify poisons (alcohol)
Golgi: modify, package, and transfer macromolecules
Mitochondria: make energy needed for functions of liver
Glycosomes: store sugar and regulate blood glucose |
|
|
Term
| where do the hepatocytes secrete bile into |
|
Definition
|
|
Term
|
Definition
o Receives 75% venous portal blood which went to intestines, stomach, pancreas and spleen first
o 25% of blood comes from hepatic artery |
|
|
Term
|
Definition
o Synthesis and secretion of bile acids
o Bilirubin production and excretion
o Detoxicy poisons and drugs
o Make blood proteins
o Excrete waste products
o Pick up glucose from the blood
o Store glucose as glycogen
o Process fats and AA
o Store some vitamins |
|
|
Term
| bile: what is it made of, how in general is it made |
|
Definition
o Bile acids are made from cholesterol in hepatocytes and transported and stored in gallbladder
o Bile acids are recirculated from ileum back to liver via enterohepatic circulation |
|
|
Term
| explain the process of RBC degredation, what happens to the biproducts |
|
Definition
o Reticuloendothelial system processes RBC
o Degraded Hb makes biliverdin (green) which is converted to bilirubin (yellow)
o Bilirubin is bound to albumin and carried to liver
o Hepatocytes take it up and conjugate with glucotonic acid via UDP glucronyl transferase
o Conjugated bilirubin is secreted into bile
o Bacterial enzymes de-conjugate into urobilinogen
o Some is absorbed back into enterohepatic circulation
o Some is converted to urobilin and stercobilin and excreted |
|
|
Term
| what are the functions of liver in carb metabolism |
|
Definition
Gluconeogenesis
Stores glucose and glycogen
Releases glucose into blood when needed |
|
|
Term
| what are the functions of the liver in protein metabolism |
|
Definition
Liver makes non-essential AA
Makes plasma proteins (albumin, clotting factors) |
|
|
Term
| what are the functions of the liber in lipid metabolism |
|
Definition
FA oxidation
Makes lipoproteins, cholesterol, and phospholipids
Converts cholesterol into bile acids |
|
|
Term
| explain liver detoxification |
|
Definition
First pass metabolism: liver sees toxins absorbed from GI before the rest of the body
Bacteria are phagocytosized via kupffer cells
Enzymes modify endogenous and exogenous toxins to make them water soluble
Phase I reactions: catalyzed by cytochrome P-450
Phase II reactions: conjugate substance with glucuronide, sulfate, AA, or glutathione |
|
|
Term
|
Definition
| UDP glucuronyl transferase is made slow after birth so it can’t conjugate bilirubin fast enough |
|
|
Term
|
Definition
May cause edema due to loss of plasma protein oncotic pressure
Hypoalbuminemia
Unable to convert ammonia from protein metabolism into urea so less will be in urine |
|
|
Term
| gall stones: cause, symptoms |
|
Definition
Bile salts crystalize to form them
Intermittent pain, obstruction, infection, fever, vomiting |
|
|
Term
| hypoalbuinemia: cause, symptom |
|
Definition
Caused by liver failure
Edema due to loss of plasma protein |
|
|
