Digestive System

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A.K.A “GI” System Alimentary or digestive tract

Functions Carries food for digestion Prepares food for absorption Transporting waste for elimination

“The journey” Begins in the mouth – Broken down mechanically and chemically Mastication-chewing Digestive enzymes-speed up chemical reaction Proteins  amino acids; complex sugars  simple sugars; large fat molecules  fatty acids, triglycerides – Absorption Blood stream Walls of small intestine – Fatty acids and triglycerides are absorbed in the small intestine – Elimination Solid waste, passed from body Feces collects in large bowel and exits through the anus

Mouth “Oral cavity” Hard palate- roof of the mouth Muscular soft palate – Posterior to hard palate – Separates mouth from throat Pharynx Rugae-irregular ridges Uvula-aids in production of sound and speech Tongue (mastication, deglutition) Tonsils (lymphocytes) Gums Teeth-32 permanent Three pairs of salivary glands-produces saliva, containing digestive enzymes – Parotid, submandibular and sublingual

Pharynx Muscular tube Passageway for food and air Epiglottis-prevents food from entering trachea

Esophagus Pharynx  stomach Aids in swallowing Peristalsis-involuntary contraction moving food through GI tract

Stomach Fundus-top portion Body-middle portion Antrum-lower portion Sphincters – Cardiac, esophagus  stomach – Pyloric, allows food to exit Rugae-irregular ridges

Small Intestine Pyloric sphincter  large intestine 20 feet long Villi-microscopic projections; aid in digestion Three parts – Duodenum 1 foot long “12 inch” Receives food from stomach Receives bile from liver and gallbladder Receives pancreatic juice from pancreas – Jejunum 8 feet long Connects with 3 rd section “empty” – Ileum 11 feet long Attaches to large intestine “to roll”

Large Intestine Ileum  anus Four parts – Cecum Right side connected by ileocecal sphinter Vermiform appendix hangs from cecum – Colon 5 feet long 3 divisions – Ascending colon, cecum  undersurface of liver – Transverse colon, horiz. To spleen then turns down – Descending colon, downward portion Sigmoid colon Rectum

Liver Located in RUQ Bile – Emulsification-breaking apart of fat globules so pancreas can digest Continuously released from liver Functions – Keep glucose levels normal – Removes excess glucose, glycogenesis – Converts glycogen into glucose – Converts proteins and fats into glucose, gluconeogenesis – Removal of poisons from the blood

Gallbladder Under liver Stores and concentrates bile for later use

Pancreas Exocrine gland Produces amylase and lipase-enzymes that aid in digestion Secretes insulin – Insulin is needed to release sugar from the blood to be used by cells in the body

Digestive System Diagram

4/21 Assignment! Pgs Combining forms (write in your notes) Check abbreviations with the textbook