The Digestive System

15.1

Functions: mechanical and

chemical breakdown of food

       *absorption of nutrients

Consists of alimentary canal

and accessory organs

Wall of the Alimentary Canal

Mixing Movements

Contractions mix food

with digestive juices

 

Peristalsis - pushes food

down the tube

Anatomy of the Mouth

Salivary Glands Parotid - ear, cheekSubmandibular - below jawSublingual - under tongue

Esophagus

esophageal hiatus is where it penetrates the diaphragm cardiac sphincter at entrance to stomach

STOMACH MUSCLES:   Longitudinal, Circular, Oblique

Stomach

Regions

●Cardiac●Fundic●Body (greater and

lesser curvature)●Pyloric

Stomach Lining

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 

Chyme - paste, after food has been broken down, released then into the duodenum via the pyloric sphincter valve

Rugae - folds within stomach

Gastric Pits contain glands to make juices 

PANCREAS - secretes insulin which breaks down sugars

Pancreatic Juice also breaks down fat

 Liver

 1 large right lobe  | 1 smaller left lobe

Liver - ducts and vessels

Hepatic duct --> to common bile duct

Hepatic portal vein - circulates blood through liver

Liver Functions1.  blood glucose levels2.  breakdown of lipids and fats3.  protein metabolism4.  stores vitamins5.  destroys damaged RBCs6.  removes toxins7.  secretes bile

Remember Bili Lights?

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. 

Gall Bladder - under liver          cystic duct --> common bile duct          stores bile, digests fat                 *gallstones may form

 

Small Intestine

 Starts at the pyloric

sphincter

1.  Duodenum

2.  Jejunum

3.  Ileum

 

*Mesentery 

Membrane holds it

together,  contains

blood vessels

Greater Omentum

a  "curtain-like" membrane that covers the intestines, stores fat and lays like a drape

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:

ABSORPTION

Large Intestine 

Cecum 

Appendix

 Colon (4 parts)

    Cecum

    Ascending

    Transverse

     Descending

     Sigmoid

 

 

Rectum

 

Anus

Function of Large IntestineSecretes mucus,  reabsorbs water, contains bacteria to aid in digestion  (intestinal flora)

Mass Movements (defecation) - removes undigested food

The main job is  WATER REABSORPTION...

stomach

cecum

appendix

ascending colon

transverse colon

descending colon

sigmoid colonrectum

1.  esophagus2.  liver3.  stomach4. pyloric sphincter5.  duodenum6.  pancreas7.  jejunum8.  ileum9.  cecum10. appendix11.  ascending colon12.  descending colon13.  sigmoid colong14.  anus

Disorders of the Digestive System

 

GERD

 

Gastroesophageal

reflux disease

STOMACH ULCERS

Lactose Intolerance  Inability to digest milk, can cause stomach upset

Appendicitis

Hernia

intestines poke through abdominal muscles

Gallstones  (Cholelithiasis)

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.

Gallstones within the gall bladder

Gastric Bypass Surgery