Digestive System Eden Area ROP Medical Careers

Functions Digestion: Breaking down food mechanically and chemically Absorption: passage of substances through walls of digestive system into fluids/tissues Elimination: getting rid of waste that is not needed by the body

Alimentary canal Definition: long muscular tube that begins at the mouth and ends at the anus

The Digestive System

Organs of the Digestive System Mouth: chemical and mechanical breakdown of food starts -Mechanical: chewing and tongue -Chemical: salivary glands Pharynx: throat Epiglottis: flap like structure that covers trachea and opens and closes to prevent food from entering lungs.

Esophagus: long tube that connects the mouth to the stomach - uses peristalsis (wavelike muscle movement that pushes food through the digestive system) Stomach: muscular sac that receives food/liquid from esophagus – Breaks down food using stomach muscles and gastric juices – Stores food Organs of the Digestive System

Small intestine: long winding tube that digestive matter enters after stomach 3 sections: Duodenum Jejunum Ileum Organs of the Digestive System

Appendix: small sac located at the beginning of large intestine Appendicitis: Obstruction of the opening of the appendix causing digestive matter and mucus to become trapped and bacteria to multiply

Large intestine: receives digestive matter from the small intestine Sections: – Cecum – Ascending colon – Transverse colon – Descending colon – Sigmoid colon – Rectum – Anus

Absorption of substances 90% of all nutrients are absorbed in the small intestine. Liquid is absorbed as the digestive matter passes through the large intestine.

Accessory Organs Liver: – Produces bile (digestive juice that absorbs fat) – Filters out harmful substances – Stores vitamins/minerals – Recycles iron & hemoglobin from worn out RBCs

Accessory Organs Gallbladder: – stores bile and releases it into duodenum as needed Pancreas – Secretes insulin – Secretes glucagon – Produces pancreatic juices that help breakdown food

Conditions of the Digestive System Hepatitis: inflammation of the liver caused by a virus or poison – Hepatitis A (HAV): ingestion of fecal matter from contaminated food or drinks. – Hepatitis B (HBV): Contact with infectious blood, semen, and other body fluids from having sex with an infected person, sharing contaminated needles, or from an infected mother to her newborn. – Hepatitis C (HCV): Contact with the blood of an infected person, primarily through sharing contaminated needles to inject drugs. There is no vaccine for Hepatitis C.

Conditions of the Digestive System Cirrhosis: a progressive degeneration of the liver – Cirrhosis has various causes but the most common are heavy alcohol consumption, chronic hepatitis C and obesity

Sphincter: circular muscles that constrict to close off the passageway and relaxes to allow materials to pass through the opening. – Cardiac Sphincter, at the top of the stomach – Iliac Sphincter, at the bottom of the stomach – Ileocecal Valve separates the small intestine from the large intestine – Involuntary Anal Sphincter, which is responsible for generating the urge to defecate. – Voluntary Anal Sphincter, which allows one to control defecation.