Gastrointestinal III Flashcards by Tim Agee

Border between the duodenum and jejunem:

Duodenojejunal flexure

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How long is the duodenum?
Jejunem?
Ileum?

10-12 inches
8 feet
12 feet

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What are the 3 surface levels of the small intestine?

Plicae curculares (macrovilli)
Villi
Microvilli

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What is at the bottom of a villus?

Crypt of Liberkuhn

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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

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Name 4 cell types in a Crypt of Liberkuhn.

Goblet
Enteroendocrine
Regenerative
Paneth

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What does an enteroendocrine cell secrete?

3 things

CCK
Secretin
GIP

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What do Paneth cells secrete?

Lysozyme

and other bacterial agents

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What morphological cell type is found in the intestine?

Columnar epithelial

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T/F

Enzymes in the stomach can break down carbs

False

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3 disaccharides:

Sucrose
Lactose
Maltose

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What degrades polysaccharides into disaccharides and oligosaccharides?

Pancreatic amylase

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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

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How does Fructose enter the intestinal cell?

What type of transport is this?

GLUT5

Facilitated diffusion

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Once in the enterocyte, how do monosaccharides exit to the capillaries?

What type of transport is this?

GLUT2

Facilitated diffusion

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What does SGLT1 require?

Na+ cotransporter

enters with - goes same direction as glc/galactose

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What is absent is Lactose Intolerance?

Lactase

*leads to fermentation

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How does the stomach break down proteins?

Incompletely denatures with Pepsin

not broken down into single AA’s

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Where does protein break down into individual AA’s?

What does this? (2 things)

Brush border

Aminopeptidases and Proteases

*proteases = active pancreatic enzymes

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Name 3 secondary brush border enzymes that break down protein?

Amino-oligopeptidase
Aminopeptidase
Dipeptidyl aminopeptidase

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How are single AA’s and small peptides transported into the enterocyte?
(2 ways)

SGLT1
(with Na+)

GLUT5 Facilitated diffusion
(same as Frc)

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What is the 1st step a Fat Globule goes through once in the duodenum?

Emulsification

by bile acids

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What 2 things coat an emulsification droplet?

Lecithin (phospholipid)

Bile acids

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What breaks down an emulsification droplet into 2 FFA’s and a monoglyceride?

Pancreatic Lipase

Colipase

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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