THE DIGESTIVE SYSTEM

DIGESTIVE SYSTEM Also called the Gastrointestinal System

Responsible for the physical and chemical breakdown of food.

System consists of the Alimentary Canal and its accessory organs Alimentary Canal-Long tube begins at the mouth and includes: mouth, pharynx,

esophagus, stomach, small intestine, large intestine and anus Accessory Organs: Salivary glands, tongue, teeth, liver, gallbladder and pancreas

THE MOUTH AKA Buccal Cavity

Function to take in food, taste it, physically break it down by teeth, lubricate it and partially digest it with saliva and swallow

Teeth physically break food down by chewing and grinding it through a process called mastication

The Tongue contains special receptors called taste buds that can taste (sweet, salty, sour and bitter), also aides in chewing and swallowing food

The Hard Palate-boney structure that forms the roof of the mouth and separates the mouth from the nasal cavities

Soft Palate-Seperates the mouth from the nasopharynx, the Uvula a cone shaped muscular structure hangs from the middle of the soft palate and prevents food from entering the nasopharynx during swallowing.

THE MOUTH Salivary Glands

Three glands: Parotid, Sublingual, and Submandibular

Saliva lubricates the mouth during speech and chewing and moistens food so that it can be swallowed easily.

Contains an enzyme called Salivary Amylase that begins the chemical breakdown of carbohydrates, or starches into sugars that can be taken into the body.

Once food has been chewed and mixed with saliva it is called a bolus.

THE MOUTH

THE PHARYNX Tube that carries both air and food

Air goes to the trachea

Food goes to the Esophagus

When food is swallowed muscle action causes the epiglottis to close over the larynx preventing the bolus from entering the trachea.

Bolus is force into the esophagus

THE ESOPHAGUS Muscular tube dorsal to the

trachea

Receives bolus from pharynx and delivers it to the stomach

Relies on rhythmic(wave like) involuntary muscle contractions called peristalsis

Peristalsis moves food in a forward direction through out the remainder of the alimentary system

PERISTALSIS

THE STOMACH Enlarged section of the alimentary canal

Mucus membrane of the stomach contains folds called Rugae that disappear as the stomach fills with food, allowing for expansion.

The Cardiac Sphincter- a circular muscle between the esophagus and stomach closes after food enters keep it from traveling back up the esophagus

The Pyloric Sphincter-Circular muscle between the stomach and small intestine keeps food in the stomach until it is ready to enter the small intestine, usually 2-4 hours after it enters

During that time the bolus is converted into a semifluid material called Chyme, by gastric juices.

Gastric Juices are made of; Hydrochloric Acid (kills bacteria, facilitates iron absorption and activates Pepsin), Lipase (starts chemical breakdown of fats), Pepsin (chemical break down of proteins)

THE STOMACH

THE SMALL INTESTINE Coiled section of the alimentary canal that is approximately 20 feet in length and

1 inch in diameter.

Divided into three sections: Duodenum, Jejunum and the Ileum

Digestion is completed in the small intestine and products are absorbed directly into the blood stream for use in the body

Many intestinal juices act on the various nutrients to break them down to usable forms. These juices originate in accessory organs, gall bladder, pancreas and liver

The walls of the small intestine are lined with finger like structures called Villi.

Villi contain capillaries and lacteals which absorb nutrients and either take them to the liver for direct release into the system or to the thoracic duct where they are stored or released depending on nutrient and need

Small intestine empties into Cecum via ileocecal valve which prevents waste from returning into small intestine

THE SMALL INTESTINE

THE LARGE INTESTINE Final section of the Alimentary Canal

Five feet in length and 2 inches in diameter

Absorbs water and any remaining nutrients, primarily stores indigestible materials before elimination from the body, synthesizes B-vitamins and vitamin k via bacteria present.

Divided into series of sections Cecum-connects to small intestine, contains appendix Colon-Three sections, Ascending, Transverse, Descending (connects to sigmoid

colon) Sigmoid Colon S shaped section that connects to Rectum Rectum final 6-8 inches of intestine which stores waste product Anal Canal-Narrow canal that ends the rectum has a hole called the anus in which

waste material leaves the system

THE LARGE INTESTINE

ACCESSORY ORGANS The Liver-Largest gland in the body

Located upper right quadrant of the body

Secretes bile which is used to emulsify fats

Bile makes fats water soluble which is necessary for absorption

Liver stores sugar as glycogen and releases it into blood stream when needed

Produces Heparin for clot prevention, blood proteins fibrinogen and prothrombin that aide in clotting and cholesterol

Detoxifies the blood contaminated with alcohol, pesticides, or bacteria

THE LIVER

THE GALLBLADDER Small muscular sac under the

liver attached by connective tissue

Stores and concentrates bile

When need it contracts squeezing bile out of the cystic duct into the common bile duct which empties into the duodenum

THE PANCREAS Glandular organ located behind the stomach

Processes pancreatic juices which contain enzymes that digest food

Enter the duodenum through the pancreatic duct

Enzymes include: Pancreatic amylase (breaks down sugar), Trypsin and chymotrypsin (break down proteins), Lipase and steapsin to (break down fats)

Produces Insulin, which is secreted into the blood stream, helps with metabolism and converting glucose into ATP

PANCREAS

PROBLEMS OF THE SYSTEM Appendicitis

Acute inflammation of the appendix

Usually results from obstruction or infection

Symptoms include: generalized abdominal pain, later localized to the lower right quadrant, nausea and vomiting, mild fever, elevated white blood cell count

If ruptured infection will spill into peritoneal cavity causing serious infection called peritonitis

Treated with appendectomy (removal of appendix)

PROBLEMS OF THE SYSTEM Cirrhosis

Chronic destruction of liver cells accompanied by formation of scar tissue and lose of liver function

Causes include: hepatitis, bile duct disease, chemical toxins, malnutrition associated with alcoholism

Symptoms; liver enlargement, anemia, indigestion, nausea, edema in the legs and feet, hematemesis, nose bleeds, jaundice, liver failure

Treatment directed toward preventing further damage to the liver, Transplant is an option.

PROBLEMS OF THE SYSTEM Constipation

Fecal matter remains in the colon for too long

Causes excessive reabsorption of water

Matter becomes hard, dry and difficult to eliminate, which leads to poor bowel habits, chronic laxative use, “lazy” bowel

Associated with diet low in fiber and certain digestive diseases as well as medication use

Treatment includes; high fiber diet, adequate fluids and exercise, laxatives on occasion

DIARRHEA Frequent watery stools

Caused by; infection, stress, diet, irritated colon and toxic substances

Very dangerous in infants and small children due to excessive fluid loss

Treatment: eliminate cause, adequate fluid intake and modifying diet

PROBLEMS OF THE SYSTEM Diverticulitis

Inflammation of the pouches that form in the intestine as the mucosal lining pushes through the surrounding muscle.

Results in abscess or rupture leading to peritonitis

Symptoms include: abdominal pain, irregular bowel movements, flatus, constipation or diarrhea, abdominal distension, low grade fever, nausea and vomiting

Treatment; antibiotics, stool softeners, pain medication, high fiber diet, Sugery

PROBLEMS OF THE SYSTEM Gastroenteritis

Inflammation of the mucus membrane that lines the stomach and intestinal tract

Causes include; food poisoning, infection, and toxins

Symptoms: Abdominal cramping, nausea, vomiting, fever, diarrhea

Treatment; rest, increased fluid intake, antibiotics, intravenous fluids, and medications to slow peristalsis

PROBLEMS OF THE SYSTEM Hemorrhoids

Painful dilated or varicose veins of the rectum and or anus

Caused: straining to defecate, constipation, pressure during pregnancy, laxative abuse, insufficient fluid intake, prolonged sitting of standing

Symptoms; pain, itching, and bleeding

Treatment; high fiber diet, increased fluid intake, stool softeners, sitz bath, warm compress, surgical removal

PROBLEMS OF THE SYSTEM Hepatitis

Viral inflammation of the liver Type A is highly contagious and is

transmitted through food and water contaminated through the feces of and infected person

Other Types include B, C, D and E Symptoms: fever, anorexia,

nausea, vomiting, fatigue, dark colored urine, clay colored stool, myalgia, enlarged liver, and jaundice

Treatment; rest, diet high in protein and low in fat, transplant if severe damage

PROBLEMS OF THE SYSTEM Hernia

Internal organ pushes through a weakened area or natural opening in a body wall

Hiatal Hernia is when the stomach pushes through the diaphragm into the chest cavity Symptoms; heartburn, stomach

distension, chest pain, difficulty swallowing

Treatment; bland diet, small frequent meals, staying upright after eating, surgical repair

Inguinal Hernia Part of small intestine pushes

through the inguinal rings of the lower abdominal wall

Push back through opening Surgically reduce if nessecary

PROBLEMS OF THE SYSTEM

PROBLEMS OF THE SYSTEM Pancreatitis

Inflammation of the pancreas due to enzymes beginning to digest the pancreas itself

Can lead to hemorrhage and shock if the blood vessels are damaged

Causes by alcoholism or blockage due to gallstones

Symptoms; severe abdominal pain, nausea, vomiting, diaphoresis, and jaundice

Treatment; removal of gallbladder, removal of alcohol and nutrient intervention if alcoholism is the cause

PROBLEMS OF THE SYSTEM Peritonitis

Inflammation of the peritoneal cavity usually occurring when intestine ruptures

Ruptured appendix or gallbladder most likely cause

Symptoms; abdominal pain, distension, fever, nausea, vomiting

Treatment; antibiotics, surgical repair of the intestine

PROBLEMS OF THE SYSTEM Ulcer

Open sore in lining of digestive tract

Peptic include gastric and duodenal ulcers

Major cause is bacteria Symptoms; burning pain,

indigestion, hematemesis, melena Treatment; antacids, bland diet,

decreased stress, avoidance of irritants, antibiotics, pepto-bismol, surgery

PROBLEMS OF THE SYSTEM Ulcerative Colitis

Severe inflammation of the colon Accompanied by formation of

ulcers and abscesses Caused by stress, food allergy,

autoimmune reaction Symptom; diarrhea with blood, pus

or mucus, weigh loss, abdominal pain, anemia, anorexia

Treatment; control inflammation, reduce stress, proper nutrition, avoid substances that aggravate the condition, Surgery(Colostomy Bag)