Gastrointestinal system part 1 (long)

role of gastrointestinal tract

digests food into usable nutrients and elimination of waste products

food

energy

proteins calories per gram

4

carbohydrates calories per gram

4

fat calories per gram

9

BMR

basale metabolic rate

adult bmr

10 cal/lb

types of diet prescription

full

clear liquid

soft

specialized

route of administration

full

all food

clear liquid

water

specialized diet eg

low sodium

parts of the Gi

- GI tract

- accessory organs

Gi tract

alimentary canal from the oral cavity to the rectum

accessory organs

salivary glands, liver, glallbaldder, pancrease

digestive functions

- transport

- absorption

- enzymes for digestion

tranport

peristalsis (stomach and intestine)

Absorption

villi in small intestine and water reabsorption into large intestine

enzymes for digestion

stomach HCL, and enzymes; pancreatic juice; bile

upper Gi

stomach

stomach

gastric pits

gastric pits

indented depression linned with mucous cells and specialized gastric cells

stomach secretions

- HCL acid

- Pepsinogen

parietal cells secreted

Hydrochloric acid

chief cells secreted

pepsinogen

how much hydrochloric acid is secreted per day

1-3 L

Pepsinogen activation

activated by HCL into pepsin

parietal cell secretion of HCl is caused by

stimulation that activates H/K-ATPase proton pump

H/K-ATPase proton pump is activated by

gastrin

histamine

acetylcholine

gastrin is secreted from

g cells

histamine is secreted from

endocrine cells

acetylcholine is secreted from

PSNS

PSNS

parasympathetic nervous system

gastrin works on what receptors

Cholecytokinin receptors

g cells are what kind of cells

enteroendocrine

enteroendocrine

hormone-producing cells in the GI tract

what receptors does histamine work on

H2 receptor

acetylcholine works on what receptors

ACH receptors

benefits of HCL

chemical digestion of food

destruction of pathogens (reduced numbers)

nutrient absorption

intrinisc factor

involved in nutrient absorption of vitamin B12

ferrous iron

ferric iron Gi absorption

Functions of Vitamin B12

- helps with a healthy brain and nervous system

- helps form DNA and RNA

- helps form RBCS

Prostaglanding E2

stimulates mucous foveolar cells

- bicarbonate and mucosu secretion

protective mucosal layer in the stomach

pH of dudoenum and Jejuum

7

secretions in duodunum and jejunum

- alkaline pancreatic juice

- bile

- alkaline serous fluid produced by the intestinal mucosa

- brush border enzymes

amount of alkaline serous fluid produced by the intestinal mucosa

2L/day

alkaline mucus

This neutralizes acidic chyme from stomach, protects the mucosa, and provides optiaml pH (7-8 approx) for pancreatic enzymes

alkaline intestinal juice

water, electrolytes, mucus, and dilutes chyme and provides a medium for enzyme activity

brush border enzymes locations

jejumum

Brush border enzymes

attached to enterocyte microvilli not free secretions

exmaples of brush border enzy es

disaccharidases, peptidases, enterokinase

HCL acid control required for

- reflux and gastroesophageal reflux disease

- peptic ulcer disease

peptic ulcer disease locations

gastric

duodenal

charecteristics of reflux

- gastric contents into the esophagus

- burning sensations "heart burn”

persistent reflux

GERD

pathophysiology of GERD + reflux

- transient relaxations of esophageal sphincter allows reflux

- delayed gastric empyting

causes of improper esophageal sphincter relaxation

- diets/foods

- obesity

- pregnancy

- aging

causes of delayed gastric emptying

- stress

- immobility

- overeating

- congenital sundromes

clinical presentation of GERD

- pain

- decreased appetite

- bleeding

- respiratory signs and symptoms if inhaled

GERD pain

heart burn, chest pain

GERD related bleeding

slow and ongoing, causing low RBCS and hematemesis

Complications of GERD

- weight loss

-- reflux esophagitis

- respiratory airway erosion

- barett's esophagus

reflux esophagitis

- erosion and inflammation of esophagus

reflux esophagitis increases risk for

esophageal cancer

respiratory/airway erosion

only occurs if reflux enters the repiratory tract

Barrett's esophagus

abnormal esophagus linning

risk factors for Barrett's Esophagus

- male

- obesity

- smoking

- caucasian

- increased age

- reflux or GERD

treatment of GERD

- avoid irritants

- decreased acidity drugs

- surgery

surgery for treatments of GERD

fundoplication

fundoplication

surgeon wraps the upper part of the stomach called the fundus around the lower esophageal sphincter preventing stomach contents from refluxing into the esophagus

avoiding GERD irritants adjunct

- small meals

- patient positioning

Three types of drugs for treatment of GERD in upper GI

- antacids

- proton pump inhibitors

- H2 receptor antagonists

antacids are

alkaline agents

antacids MOA

increase stomach pH

do antacids decrease HCl secretion

no

what does antacid treatment do

relief symptoms

when are antacids not recommended

persistent reflux

what schedule are antacids

unscheduled

Caution of antacids

- have high drug-drug interactions, therefore must take 2 hours before or two hours after taking other medications

antacid drugs

sodium bi/carbonate

sodium, calcium and alginate

aluminum hydroxide

Magnesium hydroxide

aluminum hydroxide and magnesium hydroxide

calcium carbonate

calcium carbonate and magnesium hydroxide

vismuth subsalicylate

alka-seltzer, eno

sdoium bi/carbonate

gauiscon

aosium xLXIUM ns LFINrw

amphajel

aluminum hydroxide

milk of magnesium

magnesium hydroxide

Maalox, Diovol

aluminum hydroxide and magnesium hydroxide

tums, caltiate

calcium carbonate

Rolaids

clacium carbonate and magnesium hydroxide

pesto-bismol

bismuth subsalicylate

aluminum side effects

constipation

magnesium side effects

diarrhea

calcium side effects

kidney stones

Sodium side effects

high BP

PPIs

proton pump inhibitors

proton pump inhibitors

binds to H+K+-ATPase enzymes to inhibit the proton pump and prevent HCl acid secretion

PPI drugs

omeprazole

lansoprazole

pantoprazole

omeparazole

losec

lansoprazole

Prevacid

pantoprazole

pantoloc

PPI efficacy

higher than H2 receptor blockers

PPI half life

longer than H2 receptor blockers therefore good for chornic releif

longterm PPI use

RX