The Gastrointestinal System The Virtual Autopsy

The Gastrointestinal System ~A Major part of the Digestive System~ -Digestion -Absorption -Excretion

~Important Organs~ 1. The Esophagus: Tube that connects the Pharynx with the Stomach. After food is chewed, it is passed through this tube and into the stomach 2. The Stomach: Where both mechanical and chemical digestion occurs, stores food, controls the rate at which food enters the intestines

~Important Organs~ 3. The Small Intestine: Finishes process of digestion, absorbs the nutrients, passes residue into the large intestine 4. The Pancreas: Secretes enzymes to aid in digestion of food in the small intestine

Important Organs continued... 5.The Large Intestine: Reabsorbs water and maintains the fluid balance of the body, absorbs vitamins, processes undigested material, stores waste 6. Liver: Produces bile and emulsifies fats BILE: neutralizes chime Breaks down and recycles red blood cells 7. Gallbladder: accessory gland that stores bile -The body can function without the gall bladder

Specialized Cells Mucous Cells: 1. specialized to secrete mucus 2. movement; protective lining 3. located in the mouth, esophagus, stomach, intestine (Goblet Cells) Stem Cells- divide to replace dead cells so that they can function properly

lining of the intestine that absorbes the nutrients across the plasma membrane into connective tissues and capillries. Columnar epithelial cells, scattered individually on the absorptive cells Secrete a particular hormone that influences gastrointestinal secretion and motion. Stomach=Enteroendocrine Cells Intestine= Islets of Langerhans-secrete insulin. Endocrine Cells Absorptive Cells

They secrete digestive enzymes (pepsins) in the stomach Chief Cells Hepatocytes cuboidal cells in Liver Functions: secrete bile, create urea and plasma proteins, and metabolize cholesterol

Source Enzyme Food Product Mouth Salivary Amylase Polysaccharides (carbohydrates) Maltose Stomach Pepsin Proteins Peptides Pancreas Pancreatic Amylase Trypsin Lipase Polysaccharides Proteins Fats Maltose Peptides Fatty Acids Glycerol Small Intestine Maltase Peptidases Maltose Peptides Glucose Amino Acids I m p o r t a n t ENZYMESENZYMES

Peptic Ulcers---!!OH NO!!!=[ You might ask "What is a peptic ulcer?!"... Peptic Ulcers are erosions, or open soars, in the inner lining of the stomach. AND when you talk about peptic ulcers, we cant forget about... H pylori A bacterium that infects the stomach or the first part of the small intestine

Peptic Ulcers... Symptoms & Treatments {Symptoms} -Abdominal Pain (most common) -Nauseous -Bloody Stool/Vomit -Chest pain [Treatments] -QUIT SMOKING >:O -Acid blocking medication -Bowel rests -Nasogastric tubes

Gastritis What causes Gastritis Heavy consumption of alcohol Certain medications o Aspirin o Nonsteroidal anti-inflammatory, such as ibuprofen Bacterial infections, such as Helicobacter pylori, a bacteria that lives in the mucous lining Pernicious anemia – form of anemia that occurs when the stomach lacks a naturally occurring substance needed to properly absorb and digest vitamin B12 Sometimes after major surgeries Bile reflux- a backflow of bile into the stomach from the bile tract

How do you know you have gastritis? Symptoms: Nausea Vomiting Loss of appetite Belching or bloating Burning ache or pain in the stomach Black stool Acute Gastritis brings sudden pain and is more likely to cause nausea. Chronic Gastritis occurs over a period of time associated with gradually increasing pain and loss of appetite

Testing and Treatment Diagnosis: Blood test- to check the presence of H. pylori Breath test- simple test can evaluate if infected by H. pylori Stool test Upper gastrointestinal endoscopy Upper gastrointestinal X-ray Treatment : Antacids- to reduce stomach acids, which cause the sharp pains. Antibiotics- to rid the H.pylori infections If gastritis is caused by pernicious anemia, B12 vitamin shots will be given.

Crohn's Disease (IBD) Etiology: No real known cause, several theories but none proven Hereditary, usually passed down through families Symptoms: More common: Abdominal pain, diarrhea, weight loss Less common: poor appetite, fever, night sweat, rectal pain and bleeding

Crohn's Disease (cont.) Treatment: Drug therapy: anti-inflammatory medication, immunosuppressive agents, infliximab Surgery: manages possible complications with disease, removes infected, inflamed portion of the digestive tract o Most Crohn's patients will need surgery at one point during illness. No cure for disease, like cancer can only go into remission

Cholera x Etiology: Bacterium Vibrio cholerae infects intestines, often mildly More common in underdeveloped countries with poor water filtration and sewage systems Symptoms: Most display no symptoms Severe cases: watery diarrhea, vomiting, muscle cramps Death only caused in undetected cases where patient dies of dehydration

Cholera (cont.) Treatment: Requires immediate treatment, otherwise death may occur within hours Rehydration o ORT: Oral Rehydration Therapy o Intravenous Fluid Replacement o Without rehydration, 50% of patients die Antibiotics: used to shorten illness, but rehydration is still necessary

~Connections with Other Systems~ 1. With the Circulatory System: The circulatory system transports nutrients throughout the body as well as hormones that control the speed of digestion 2. With the Excretory System: Ejection of undigested material. Digestion system works parallel with system

~Connections with other systems~ 3. With the Endocrine System: Secretion of digestive hormones like gastrin to start digestion or release bile 4. With the Nervous System: Muscles of digestive tract are under control of the autonomic nervous system 5. With the Muscular System: Muscles make up the digestive tract for peristalsis along with stomach for mechanical digestion