The Digestive System. Chapter 15. 15.1 Functions: mechanical and chemical breakdown of food *absorption of nutrients Consists of alimentary canal and accessory organs. Wall of the Alimentary Canal. 15.2 Characteristics of the Canal.
Functions: mechanical and chemical breakdown of food
*absorption of nutrients
Consists of alimentary canal and accessory organs
1. Mucosa - protects tissues and carries absorption
2. Submucosa - glands, blood vessels, nerves
3. Muscular Layer - smooth muscle tissue, circular & longitudinal fibers, pushes food (PERISTALSIS)
4. Serosa (serous layer) - visceral perioneum, outer covering of the tube, lubricates surfaces (serous fluid)
Contractions mix food with digestive juices
Peristalsis - pushes food down the tube
Parotid - ear, cheek
Submandibular - below jaw
Sublingual - under tongue
esophageal hiatus is where it penetrates the diaphragm
cardiac sphincter at entrance to stomach
Gastric Juices contain acids that break down food - secreted by gastric glands
PEPSIN - most important digestive enzyme for breaking down food
Mucus prevents stomach from digesting itself
Rugae - folds within stomach
Gastric Pits contain glands to make juices
Pancreatic Juice also breaks down fat
1 large right lobe | 1 smaller left lobe
Hepatic duct --> to common bile duct
Hepatic portal vein - circulates blood throughout liver
1. blood glucose levels
2. breakdown of lipids and fats
3. protein metabolism
4. stores vitamins
5. destroys damaged RBCs
6. removes toxins
7. secretes bile
Using bili lights is a therapeutic procedure performed on newborn or premature infants to reduce elevated levels of bilirubin. If blood levels of bilirubin become too high, the bilirubin begins to dissolve in the body tissues, producing the characteristic yellow eyes and skin of jaundice.
cystic duct --> common bile duct
stores bile, digests fat
*gallstones may form
Starts at the pyloric sphincter
Membrane holds it together, contains blood vessels
a "curtain-like" membrane that covers the intestines, stores fat and lays like a drape
Intestinal villi - increase surface area to absorb nutrients, connect to vessels
The main function of the small intestine is to secrete chemicals that break down food and carry the nutrients away in the blood stream. In one word:
Colon (4 parts)
Cecum Ascending Transverse Descending Sigmoid
Secretes mucus, reabsorbs water, contains bacteria to aid in digestion (intestinal flora)
Mass Movements (defecation) - removes undigested food
The main job is
4. pyloric sphincter
11. ascending colon
12. descending colon
13. sigmoid colong
Gastroesophageal reflux disease
is caused by eating food and drinking water infected with a virus called HAV. While it can cause swelling and inflammation in the liver, it doesn't lead to chronic disease. Almost everyone who gets hepatitis A has a full recovery, some may need hospitalization
Many people are recommended to receive hepatitis A vaccine, including people at increased risk for exposure to hepatitis A virus infection and people who are more likely to get seriously ill if infected with the virus
Some people never develop symptoms, others develop chronic symptoms that stay with them their whole life.
Hepatitis C is caused by the virus HCV. It is spread the same way as hepatitis B, through contact with an infected person's blood, semen, or body fluid (see above).
Like hepatitis B, hepatitis C causes swelling of the liver and can cause liver damage that can lead to cancer. Most people who have hepatitis C develop a chronic infection. This may lead to a scarring of the liver, called cirrhosis.
Blood banks test all donated blood for hepatitis C, greatly reducing the risk for getting the virus from blood transfusions or blood products.
Loss of appetite
Pain with passing stool (tenesmus); bloody stool
Persistent, watery diarrhea
The muscles in the bowel wall may contract too forcefully or too weakly, too slowly or rapidly at certain times.
Inability to digest milk, can cause stomach upset
intestines poke through abdominal muscles
Without healthy villi, a person becomes malnourished, no matter how much food one eats.
Gallstones are made from cholesterol and other things found in the bile. They can be smaller than a grain of sand or as large as a golf ball.
Colonoscopy is a screening technique to detect cancer.
See Katie Couric's Colonoscopy