Gastrointestinal III Flashcards
Border between the duodenum and jejunem:
Duodenojejunal flexure
How long is the duodenum?
Jejunem?
Ileum?
10-12 inches
8 feet
12 feet
What are the 3 surface levels of the small intestine?
Plicae curculares (macrovilli)
Villi
Microvilli
What is at the bottom of a villus?
Crypt of Liberkuhn
What type of cell is generally found on the surface of the vili?
What’s found on their surface?
Surface absorptive cells
Brush border enzymes
Name 4 cell types in a Crypt of Liberkuhn.
Goblet
Enteroendocrine
Regenerative
Paneth
What does an enteroendocrine cell secrete?
3 things
CCK
Secretin
GIP
What do Paneth cells secrete?
Lysozyme
and other bacterial agents
What morphological cell type is found in the intestine?
Columnar epithelial
T/F
Enzymes in the stomach can break down carbs
False
3 disaccharides:
Sucrose
Lactose
Maltose
What degrades polysaccharides into disaccharides and oligosaccharides?
Pancreatic amylase
How are glucose and galactose absorbed in the gut?
What type of transport is this?
SGLT-1 cotransporter (w/ Na+)
Secondary active transport
this goes against conc. gradient
How does Fructose enter the intestinal cell?
What type of transport is this?
GLUT5
Facilitated diffusion
Once in the enterocyte, how do monosaccharides exit to the capillaries?
What type of transport is this?
GLUT2
Facilitated diffusion
What does SGLT1 require?
Na+ cotransporter
enters with - goes same direction as glc/galactose
What is absent is Lactose Intolerance?
Lactase
*leads to fermentation
How does the stomach break down proteins?
Incompletely denatures with Pepsin
not broken down into single AA’s
Where does protein break down into individual AA’s?
What does this? (2 things)
Brush border
Aminopeptidases and Proteases
*proteases = active pancreatic enzymes
Name 3 secondary brush border enzymes that break down protein?
Amino-oligopeptidase
Aminopeptidase
Dipeptidyl aminopeptidase
How are single AA’s and small peptides transported into the enterocyte?
(2 ways)
SGLT1
(with Na+)
GLUT5 Facilitated diffusion
(same as Frc)
What is the 1st step a Fat Globule goes through once in the duodenum?
Emulsification
by bile acids
What 2 things coat an emulsification droplet?
Lecithin (phospholipid)
Bile acids
What breaks down an emulsification droplet into 2 FFA’s and a monoglyceride?
Pancreatic Lipase
Colipase
What do FFA’s and Monoglycerides combine with to form micelles?
What coats the micelle?
Cholesterol
Fat soluble vitamins (ADEK)
Bile acids coat
Once the Micelle enters enterocyte, how are they repackaged into Chylomicrons?
(4 ingredients)
FFA’s and monoclycerides re-form triglycerides
phospholipids
cholesterol
protein shell
What is a lacteal?
Lymphatic capillary opening
How are chylomicrons secreted into lacteals?
Golgi packages and exocytosis
How does all fat enter the bloodsteam?
Thoracic duct
juncture subclavian and jugular veins
How long does it take after eating a fatty meal for fat to travel through lymph and enter blood?
What is this called?
Within an hour
Lipemia
What is the half-life of a chylomicron?
Less than 60 minutes
Where are chylomicrons removed from the blood?
Adipose
Liver
What do adipose and liver contain large quantities of that allows for fat absorption?
Lipoprotein Lipase
What does Lipoprotein Lipase do to a chylomicron?
Hydrolyzes Triglycerides into FA’s and glycerol
What are the 5 classes of lipoproteins?
Chylomicrons VLDL IDL LDL HDL
What does the “density” refer to in categorizing lipoproteins?
Protein coat
VLDL, IDL, LHL, and HDL are sythesized by the…
Liver
What type of lipoprotein contains low levels of TG’s and high cholesterol and phospholipid?
LDL
What type of lipoprotein contains high TG’s and moderate cholesterol and phospholipids?
VLDL
What are the only lipoproteins generally monitored?
LDL and HDL
How do Statins work?
HMG CoA Reductase inhibitors
All statin drugs end in…
statin
What is an adverse effect of statins?
Myopathy
What statin side effect refers to muscle pain or weakness without increased creatine kinase?
Myalgia
What statin side effect entails:
muscle pain/weakness
no increase creatine kinase
elevated CK
Myositis
What entails: very high CK increased creatinine dark urine myoglobunuria
Rhabdomyolysis
What is the prevalence of muscle complaints while taking statins?
1 in 10
7 risk factors for statin myopathy:
Age Small size High dose Liver/renal disease Diabetes Hypothyroidism other meds
What is the function of high dose Nicotinic Acid/Vita B3/Niacin?
Lowers lipid levels
What are the 3 preparations of Niacin used to lower lipid levels?
Immediate release
Sustained release
No-flush (inositol hexaniacinate; nicinamide)
Niacor is a _____ Niacin.
Immediate release
Niaspan and slo-niacin are _____ Niacins
Sustained/extended release
What is the most potent agent for raising HDL levels?
Niacin
T/F
The exact mechanism of Niacin’s lowering lipid levels is poorly understood
True
By how much does Niacin Lower LDL and increase HDL?
Reduce TG’s?
LDL - reduce 5-25%
HDL - increase 15-35%
TG’s - 20-50%
What percentage of population is intolerant to Niacin?
This is mediated by?
50-60%
Prostaglandin
What blunts the Niacin flushing effect?
NSAID 30 minutes prior
Name 3 Bile Acid Binding Resins:
Colestipol
Cholestyramine
Colesevalam
What 2 effects to Bile Acid binding resins have in the small intestine?
Decreased emulsification
Bile acid reabsorption prevention
*liver increases production because of latter
T/F
Resins have little effect on HDL/TG’s in blood
True
By how much can Resins decrease Plasma HDL?
30% with max dose
6 side effects of Bile Acid binding resins:
Constipation Bloating Flatulence Nausea Vomiting Dyspepsia (indigestion)
What can relieve resin side effect symptoms?
Increased dietary/supplemental fiber
7 drugs/substances Bile Acid binding Resins bind:
ADEK Folate Thiazides Tetracyclines Warfarin Propanolol Penicillin
How can drug-drug interactions be reduced when using Resins?
Stagger time
(take hours after taking medications0
Water absorption in the gut is ______ to solute movement.
Secondary
How is K+ absorbed?
Passively via solvent drag
What is the active form of Vitamin D that is responsible for Calcium absorption?
What does it do?
1,25 dihydroxycholecalciferol
Stimulated enterocyte Calbindins
How are fat soluble vitamins absorbed?
Similar to fat
How are most water soluble vitamins absorbed?
Simple diffusion
What absorbs IF-Vitamin B12 complexes?
Ileal cells
How much time does chyme spend in the small intestine?
3-5 hours
How are peristalsis and segmentation controlled?
What inhibits?
What excites?
Autonomic
Sympathetic
Parasympathetic
The Vagus nerve regulates what in the intestine?
in pancreas?
Parasympathetic segmentation/peristalsis
Secretion pancreatic enzymes
What are the longitudinal bands of the large intestine called?
Teniae coli
What are the outpouchings of the large intestine called?
Haustra
What exists between the Teniae coli?
Haustra
Where is the appendix?
Cecum
T/F
Large intestine lack villi on the mucosa.
True
What 4 cells exist in the Crypts of Lieberkuhn of the Large Intestine?
Absorptive
Goblet
Endocrine
Regenerative
Histologically, the luminal surface of the Large intestine is….
Flat
How many different species of bacteria live in the Large intestine?
500
What accounts for the slightly acidic nature of stool?
Organic acids produced by bacterial fermentation in Large intestine
T/F
Many normal intestinal flora have a low pH optimum, while many pathogens favor neutral environments.
True
T/F
Bile salts and certain drugs are metabolized in the Large intestine
True
T/F
Vitamin K, B12, and folic acid are all made by intestinal flora.
True
4 Mechanisms producing diarrhea:
Increased osmotic load
Increased secretion
Inflammation
Decreased absorption time
What causes osmotic diarrhea?
Unabsorbable substances
*think lactose intolerance
What type of diarrhea does Cholera produce?
Secretory
What type of diarrhea includes mucosal diseases?
Exudative
T/F
Parkinson’s, MS, hypothyroidism, diabetic neuropathy can all cause constipation
True
T/F
Calcium channel blockers, opiates, anti-cholinergics, diuretics, Fe supplements, aluminum antacids all cause constipation.
True
T/F
There are no structural or biochemical abnormalities in IBS
True
What is the proposed cause of IBS?
Dysregulation of intestinal motor/sensory functions modulated by CNS
*also stress a factor
What bowel disease can manifest in the mouth?
What does not?
Crohn’s
Ulcerative colitis
2 Inflammatory bowel diseases:
Crohn’s
Ulcerative colitis
T/F
Both Crohn’s and Ulcerative Colitis have a causative agent
False
Where does Ulcerative Colitis usually occur?
Colon only
Where does Crohn’s disease usually occur?
Ileum and Colon
In Crohn’s disease, the bowel wall appears thick but the inflammation is _____
In Ulcerative colitis the bowel wall appears thin but the inflammation is _____
Transmural
Limited to mucosa/submucosa
What condition results from high intraluminal pressure on weak areas of the bowel wall?
Diverticulosis
*refers to bumps on the outer colon
In Diverticulosis, the _____ layer herniates through the _____ layer.
mucosal
muscularis
When diverticulosis becomes inflamed:
Diverticulitis
What is associated with complaints of pain in the LLQ?
also nausea, vomiting, tenderness, fever, elevated WBC
Diverticulitis
What defining characteristic does acute appendicites have?
Rebound tenderness
Name 4 mechanical intestinal obstructions:
Herniation
Adhesion
Volvulus
Intussusception
What is associated with the Valsalva maneuver?
Defecation
glottis voluntarily closes, abs and diaphragm contract
T/F
Peptic ulcers, esophageal varices, hemorrhoids, blood clotting disorders all can cause GI tract bleeding
True
What refers to blood in the vomit?
Hematemesis
What type of odorous stools originate from bleeding high in the GI tract?
Melena
4 Predisposing factors for Adenocarcinoma of the Colon and Rectum:
Polyps
Long-standing UC
Genetic factors
Low fiber, high animal fat diet
T/F
Taking Niacin at night can reduce negative side effects
True
T/F
Increased dental caries is associated with Crohn’s
True
T/F
The ulcerations associated with Colitis can be expressed on the face during a flare up.
Also, oral lesions pop up during symptomatic phase
True
T/F
GERD leads to caries.
False
*although demineralization does
T/F
Chronic liver disease can lead to dearth of clotting factors that manifest as petechia in the mouth. It can also present as jaundice. Hep B is major factor.
False
Hep C is the major factor worldwide
