Digestive System

Digestive System - 1 26-1 Human Anatomy, First Edition...

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Unformatted text preview: 1 26-1 Human Anatomy, First Edition McKinley & O'Loughlin Chapter 26 Lecture Outline: Digestive System 26-2 General Structure and Functions of the Digestive System ¡ Ingest the food. ¡ Transport the food. ¡ Digest the food into smaller usable components. ¡ Absorb the necessary nutrients into the bloodstream. ¡ Expel the waste products from the body. ¡ Composed of two separate categories of organs: ¡ digestive organs ¡ accessory digestive organs . ¡ Collectively make up the gastrointestinal (GI) tract. ¡ Also called the digestive tract or alimentary canal. 3 2 26-4 General Structure and Functions of the Digestive System ¡ The GI tract organs: ¡ oral cavity ¡ pharynx ¡ esophagus ¡ stomach ¡ small intestine ¡ large intestine ¡ Form a continuous tube that extends about 30 feet (9–10 meters) from the mouth to the anus. ¡ Smooth muscle in the GI tract wall pushes materials from one end to the other. ¡ Accessory digestive organs: ¡ do not form the long GI tube, but often ¡ develop as outgrowths from and are connected to the GI tract ¡ Assist the GI tract in the digestion of food. ¡ teeth , tongue , salivary glands , liver , gallbladder , and pancreas 26-5 Digestive System Functions ¡ Ingestion ¡ Digestion ¡ mechanical digestion ¡ chemical digestion ¡ Propulsion ¡ peristalsis ¡ segmentation ¡ Secretion ¡ Absorption ¡ Elimination of wastes (defecation) 6 3 26-7 Oral Cavity (mouth) ¡ Entrance to the GI tract. ¡ Initial site of mechanical digestion (via mastication) and chemical digestion (via enzymes in saliva ). ¡ Bounded anteriorly by the teeth and lips and posteriorly by the oropharynx. ¡ Superior boundary is formed by the hard and soft palates. ¡ Floor, or inferior surface, of the oral cavity contains the tongue as well as the mylohyoid muscle covered with mucosa. ¡ Vestibule is the space between the cheeks or lips and the gums. ¡ Oral cavity proper. ¡ The lateral walls are formed by the cheeks. ¡ Lips (labia). ¡ Gingivae, or gums. ¡ Labial frenulum. 8 9 4 26-10 Palate ¡ Anterior two-thirds of the palate is hard and bony (called the hard palate ), while the ¡ Posterior one-third is soft and muscular (called the soft palate ). ¡ primarily composed of skeletal muscle. ¡ Extending inferiorly from the posterior part of the soft palate is the uvula....
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This note was uploaded on 01/16/2012 for the course BI 200 taught by Professor Potter during the Fall '11 term at Montgomery College.

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Digestive System - 1 26-1 Human Anatomy, First Edition...

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