Digestive System

• https://www.youtube.com/watch?v=_QYwscALNng

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 sugarssimple sugars; large fat

moleculesfatty 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

• Pharynxstomach• Aids in swallowing• Peristalsis-involuntary contraction moving

food through GI tract

Stomach

• Fundus-top portion• Body-middle portion• Antrum-lower portion• Sphincters– Cardiac, esophagusstomach– 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 3rd 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. 484-486 Combining forms (write in your notes)

• Check abbreviations with the textbook