cp22 - Digestive System Chapter 22 Two major parts...

Info iconThis preview shows pages 1–22. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Digestive System Chapter 22 Two major parts Alimentary canal GI tract- long hollow canal from mouth to anal canal; continuous with outside of body Oral cavity, pharynx, esophagus, stomach, small intestine, large intestine, anal canal Accessory organs Teeth, tongue, salivary glands, liver, pancreas Functions of Digestive System Mechanical and chemical breakdown of food; absorption of nutrients; elimination of waste products Mechanical Breakdown of Food Physical preparation of food for breakdown by enzymes Includes chewing, mixing of food with saliva, food churning in stomach, segmentation of food in small intestine Chemical Breakdown of Food Series of steps which breaks down large food molecules with enzymes secreted into the alimentary canal Begins in the mouth and is completed in the small intestine Absorption of Nutrients The passage of digested molecules of food, water, minerals, and vitamins from the lumen of the GI tract into the mucosal cells by active or passive transport into blood or lymph Elimination of Waste Ridding the body of indigestible byproducts of digestion Histology of GI Tract 4 Basic Layers 1. Mucosa 2. Submucosa 3. Muscularis Externa 4. Serosa Mucosa Functions: 1. Secretion of mucous, hormones, enzymes 2. Absorption of nutrients 3. Protection against infection Simple columnar epithelium atop loose areolar connective tissue and lymphatic tissue with a base of smooth muscle that controls movement of this layer Submucosa Dense CT layer with blood and lymph vessels, lymph follicles, nerve fibers Muscularis Externa Layer responsible for segmentation and peristalsis Inner circular and outer longitudinal layers of smooth muscle; thickened areas can form sphincters that act as valves Serosa This is also the visceral peritoneum; formed of areolar CT and covered by simple squamous epithelium The esophagus doesn’t have a serosa because it is in the thorax; it has an adventitia (fibrous CT) that connects it to surrounding structures in chest Salivary Glands Parotid Glands- located anterior to ear Sublingual Glands- located in floor of mouth Submandibular Glands- located under jaw Function: produce saliva- mostly water, salivary amylase, antimicrobials Saliva moistens food, starts starch breakdown, dissolves food chemicals for taste Mouth, Pharynx, Esophagus Mouth- place where mechanical breakdown of food begins with chewing Pharynx- has 2 skeletal muscle layers whose contractions propel food into esophagus Esophagus- long tube to stomach posterior to trachea; conduit for food; peristalsis (alternate waves of contraction/relaxation of muscle that propels food to stomach) Stomach Chemical breakdown of proteins begins here; food becomes chyme; upper end to esophagus is cardiac portion; fundus is top; middle is body and end is pylorus Stomach Histology...
View Full Document

This note was uploaded on 02/26/2011 for the course BIO 107 taught by Professor Smith during the Spring '11 term at NE Texas CC.

Page1 / 79

cp22 - Digestive System Chapter 22 Two major parts...

This preview shows document pages 1 - 22. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online