Gastro Intestinal

Rebecca, Jennifer,

Kenny, Michael

Purpose of GI Tract• Simplest form- tube from mouth to anus• Digestion, absorption, removal of waste

large molecules

small molecules

absorbed into blood

Mouth

• Chewing breaks down food

• Saliva:– Moistens food

– amylase enzyme starts digestion by breaking down starch

Esophagus

• Simple tube connecting mouth to stomach• Peristalsis: muscle contractions that push food down through

the esophagus

Stomach

•Sphincter: muscular ring that closes end of esophagus to prevent food and fluid from traveling back up

Stomach

• An empty adult stomach has a volume of 1/5 cup, but after a large meal, it can expand to more than 8 cups

• Stomach muscles mix food with acids and enzymes to break it down

• Glands in the stomach lining produce 3 quarts of digestive juices a day

Stomach cells

• Chief cells in Glands: produce pepsinogen, a precursor of the enzyme pepsin

• Parietal cells: secrete the hydrochloric acid of the gastric juice

• Stomach epithelium: columnar cells– Mucus-producing

Chyme

• Food ready to leave the stomach is a thick liquid called chyme

• The pylorus, a small muscular valve, keeps chyme in the stomach until it’s ready to go

Specialized Cells

Upper Tract:

• Serous- glandular epithelial cells specialized for exocrine enzyme secretion

• Mucous- secrete mucous

• Taste Buds- columnar epithelial sensory cells in clusters for tasting

Small Intestine

• Three parts of small intestine:

– Duodenum: first part, C-shaped

– Jejunum: coiled middle

– Ileum: leads to large intestine

Villi

-cover inner wall of small intestine

-microscopic

-finger-like

-used for absorbing nutrients

Large Intestine

• Functions: • Absorb water• Bacterial fermentation• Feces formation

Parts:•caecum•appendix•colon•rectum

Caecum

• Small pouch, first part of the large intestine• Accepts and stores processed material from

the small intestine and moves it towards the colon.

• Mixture of processed material contains:– undigested food (fibre) – a little bit of water – some vitamins – some minerals or salts

Appendix

• small projection sticking out from caecum

• has no known function in humans – Left over from evolution?

• Appendicitis: appendix becomes infected or inflamed– removed by surgery

Colon• Shaped like an upside-

down 'U‘• longest part of the large

intestine.

• 4 Sections:– Ascending colon: starts at

the caecum… – Transverse colon – Descending colon– Sigmoid colon: S-shaped,

connects descending colon and rectum.

Colon Function

• Mixture = feces– fiber– small amounts of water– vitamins– mucus– bacteria

• Colon absorbs most of the water, some vitamins and minerals

• Bacteria break down materials to support cells lining the colon

• Colon muscular movement feces stored in rectum

Specialized Intestinal Cells

• Absorptive

• Goblet

• Enteroendocrine

• Stem cells (present throughout GI tract)

Liver

Function

• Blood flows from hepatic artery (oxygen-rich) and portal vein (contains food)

• The liver then produces substances for a variety of functions

The liver is the largest gland in the body

Specialized Liver Cells• Hepatocytes

– form bile

– Regulate blood glucose

– Get energy from cholesterol and fat

– detoxify certain drugs and poisons

– process certain hormones and vitamin D

Specialized Liver Cells

• Kupffer- clean blood

• Fenestrated- “full of holes,” permit blood plasma flow in certain areas

PancreasFunctions

• Neutralizes acid

• Breaks down macromolecular nutrients

Gall Bladder

• storage stop between the liver and the small intestine. • fills with bile (holds ¼ cup), thickens it

Bile• yellowish-green,

pasty liquid

• contains water, bile salts and acids, pigments, cholesterol, phospholipids, and electrolytes

• Breaks up fat

Other Enzymes

• Pepsin (stomach): breaks down proteins

• Pancreatic amylase

• Pancreatic lipase

• Small Intestine disaccharidases

Peptic Ulcers

What are Peptic Ulcers?Peptic Ulcers are open sores in the lining of

the esophagus, stomach, or duodenum.

Stomach = Gastric Ulcer

Duodenum = Duodenal Ulcer

Esophagus = Esophageal Ulcer

What are Peptic Ulcers?Peptic Ulcers are open sores in the lining of

the esophagus, stomach, or duodenum.

Stomach = Gastric Ulcer

Duodenum = Duodenal Ulcer

Esophagus = Esophageal Ulcer

1) H. Pylori bacterium reaches to the mucosal cells, which secrete mucus.

2) Releases ammonia to neutralize the acid so the bacterium can survive

3) H. Pylori bacteria gather and infect the area

4) The bacteria digs itself in the mucosal cells, damaging them so that it cannot produce mucus. The acid is then able to flow and damage the lining of the stomach or duodenum, causing an ulcer

Other Etiologies

• NSAIDs (Non-steroidal anti-inflammatory drugs) such as aspirin and ibuprofen, interferes with the stomach to produce mucus

• Smoking – Nicotine in cigarettes cause the stomach to produce more acid

• Alcohol – Wears down mucus lining

• Caffeine stimulates acid secretion

• Stress and spicy food can also worsen ulcers

What are some signs tolook out for?

• If there is pain or discomfort near the abdominal area.

• Heartburn, bloating, vomiting

Symptoms that need immediate medical attention

- Difficulty swallowing, loss of weight, and blood in vomit, nausea, sudden severe pain in abdominal area.

How do you treat Peptic Ulcers?

• If the ulcer was caused by H. Pylori, treatments will include antibiotics that will destroy the bacterium so the ulcer can heal.– Amoxicillin, tetracycline

Other treatments• Acid Suppressors

– Proton pump inhibitors (PPIs)-• A Proton Pump is molecules that pumps hydrogen

ions into the stomach, making the stomach contents acidic (stomach acid).

• PPIs block the proton pump from “pumping” the hydrogen ion into the stomach, creating a less acidic environment for the ulcer to heal.

- Pepto Bismol- Coats the stomach and protects the ulcer from acid so it can heal. Pepto Bismol can also kill bacteria, including the H. Pylori bacteria.

• Stomach Protector

Crohn’s Disease

What is it?

• Crohn's disease is a form of Inflammatory Bowel Disease (IBD). Crohn’s disease is a chronic inflammatory disease of the intestines. It mainly causes ulcerations, or breaks in the lining, of the small and large intestines. Crohn’s disease can also affect other parts of the digestive system anywhere from the mouth, all the way down to the anus.

What is it?

• Crohn's disease is a form of Inflammatory Bowel Disease (IBD). Crohn’s disease is a chronic inflammatory disease of the intestines. It mainly causes ulcerations, or breaks in the lining, of the small and large intestines. Crohn’s disease can also affect other parts of the digestive system anywhere from the mouth, all the way down to the anus.

What’s the cause of Crohn’s disease?

Unknown

What do scientists believe?

• Some scientists believe the disease is caused by an infection of certain bacteria, but there is not enough convincing evidence to prove that the disease is caused by an infection.

• Some also believe it is a genetic disease.

Main Symptoms• Common

- abdominal pain

-diarrhea

-weight loss• Less Common

-poor appetite

-fever

-night sweats

-rectal pain

-rectal bleeding

Treatments

• Treatments can vary depending on the patient’s symptoms and the severity of the disease. If the symptoms are mild or absent, the patient may not need treatment at all.

Treatment Goals

• 1) induce remissions

• 2) maintain remissions

• 3) minimize side effects of treatment

• 4) improve the quality of life

What types of medicine?

• Anti-inflammatory agents such as 5-ASA compounds, corticosteroids, or topical antibiotics

• Immuno-modulators

• Other medications.

Abnormalities/Diseases

Of the Gastrointestinal System

Abnormalities and Diseases

• The gastrointestinal system can be affected by various diseases and abnormalities.

• These can include colorectal cancer, gastroenteritis (stomach flu), giardiasis, inflammatory bowel disease, intestinal malrotation, irritable bowel system, and pancreatis.

Intestinal Malrotation

• Results as birth defect where the intestines are not properly positioned during fetus development and the intestines become blocked.

• Can lead to other complications such as the formation of Ladd’s bands.

Why it happens.

• 1 in 500 babies affected.• When the bowel is misaligned during fetal development.• Occurs if the bowel is not properly moved and fails to

return to peritoneal cavity in the normal sequence.

What does it do?• Causes a volvulus which

is an intestinal twisting that can lead to blockage.

• Intestinal blockage can cause death of certain sections of the intestines.

• Can cause formation of Ladd’s bands.

• Is life threatening if not treated.

Affected Organs

• Large and Small Intestines – become twisted

• Ladd’s Bands (blue) – band of tissue formed attaching cecum to abdominal wall

• Cecum (black) – becomes displaced (pouch which is beginning of large intestine)

Symptoms

• Swollen abdominal

• Diarrhea or bloody waste

• Fever

• Little or no urine

• Pain or crying not stopping

• Rapid heart rate and/or breathing

Treatment

• Surgery to correct malrotation (varies)

• Ladd’s Procedure (most common)– Ladd’s bands divided, cut– Intestines untwisted and repositioned– Appendix removed usually, to prevent future

problems

Ladd’s Procedure

A) Abdomen cut open.

B) Move small intestines out.

C) Intestines rotated.

D) Intestines repositioned, Ladd’s Band cut.

E) End Result

Giardiasis

• Also known as “backpacker’s diarrhea” or “beaver fever.”

• Parasitic disease

• Both human and animals.

• Common disease throughout world.

• Often among campers and people who drink from open water supplies.

What Causes it?• Giardia lamblia

• Parasite infects host.

• Lives in intestines. Moves through stool (feces)

• Absorbs nutrients and releases toxins in small intestines.

Gardia lamblia

• Microscopic parasite.• Reproduces asexually.• Spreads through feces.• Life cycle consists of 4

stages. – 1. Enters body as cyst.– 2. Cysts turns into

trophozoite in stomach– 3. Attach to intestinal walls,

absorb nutrients and reproduce.

– 4. New parasites form into cysts and pass through with feces. Cycle starts again.

Insert Life cycle pic here

Effects of Giardiasis

• Presence of parasite causes immune response.

• Body attempts to “flush” out of system.

• Result is explosive diarrhea.

• Can be difficult to permanently remove from body. Lingers around for long time.

Symptoms

• Loss of appetite • Fever• Stomach cramps or pain• Flatulence • Explosive diarrhea • Watery stools• Symptoms may be mistaken for peptic

ulcer.

Treatments

• Immune system may defeat Gardia Lamblia on its own.

• Medicine and drugs used to defeat infection.

• Drugs used include metronidazole, albendazole and quinacrine.– Metronidazole is taken in by infectious

organism and upset its DNA helical structure as it is broken down.

sources• http://www.vivo.colostate.edu/hbooks/pathphys/digestion/basics/gi_microan

atomy.html

• http://kidshealth.org/parent/general/body_basics/digestive.html• http://www.lab.anhb.uwa.edu.au/mb140/CorePages/GIT/git.htm• http://digestive.niddk.nih.gov/ddiseases/pubs/yrdd/• http://www.gesa.org.au/digestive-system/large_intestine.cfm• http://www.siumed.edu/~dking2/erg/gicells.htm • https://services.epnet.com/GetImage.aspx/getImage.aspx?ImageIID=2470• http://www.vivo.colostate.edu/hbooks/pathphys/digestion/liver/bile.html• http://www.vivo.colostate.edu/hbooks/pathphys/digestion/pancreas/

index.html• http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/G/GITract.html#liver• http://www.mamashealth.com/organs/liver.asp• http://www.nutraingredients.com/Research/Colon-bacteria-need-fibre-to-fee

d-healthy-digestion

Sources• http://www.netdoctor.co.uk/medicines/100002038.html• http://heartburn.about.com/cs/articles/a/Ulcer_Treated.htm• http://digestive.niddk.nih.gov/ddiseases/pubs/hpylori/• http://hcd2.bupa.co.uk/fact_sheets/html/Peptic_ulcer.html#4• http://en.wikipedia.org/wiki/Peptic_ulcer• http://heartburn.about.com/cs/articles/a/Ulcer_Causes.htm• http://www.emedicinehealth.com/peptic_ulcers/

page3_em.htm#Peptic%20Ulcers%20Symptoms• http://heartburn.about.com/cs/articles/a/Ulcer_Symptoms.htm• http://heartburn.about.com/od/medsremedies/a/protonpumpPPIs.htm• http://en.wikipedia.org/wiki/Proton_pump_inhibitor#Clinical_use

Sources

• http://en.wikipedia.org/wiki/Giardiasis

• http://en.wikipedia.org/wiki/Giardia_lamblia

• http://www.cdc.gov/ncidod/dpd/parasites/Giardiasis/factsht_giardia.htm#transmission

• http://www.fpnotebook.com/GI/ID/GrdLmbl.htm

• http://en.wikipedia.org/wiki/Metronidazole

Sources

• http://www.medicinenet.com/crohns_disease/article.htm

• http://library.med.utah.edu/WebPath/TUTORIAL/IBD/IBD.html

Sources

• http://kidshealth.org/parent/medical/digestive/malrotation.html

• http://en.wikipedia.org/wiki/Intestinal_malrotation

• http://www.pedisurg.com/PtEduc/Malrotation.htm