Class Notes (808,146)
Canada (493,092)
BIOB34H3 (271)
Ted Petit (35)

Chapter 23.docx

4 Pages
Unlock Document

University of Toronto Scarborough
Biological Sciences
Ted Petit

Chapter 23 Digestive System • Basics - Two groups of organs 1. alimentary canal (gastrointestinal or GI tract is a continuous tube with openings at mouth and anus) 2. accessory organs (teeth, tongue, gallbladder, salivary glands, liver, pancreas) - Digestive processes 1. ingestion (eating) 2. motility (propulsion and mixing) 3. digestion (breaking down food into smaller pieces) a. mechanical - teeth, stomach, small intestine b. chemical - enzymes break down large molecules 4. absorption (small molecules absorbed into blood and lymph) 5. defecation (eliminating wastes) - Peritoneum 1. covers most organs below diaphragm a. visceral layer b. parietal layer c. peritoneal cavity with serous fluid 2. mesenteries a. fused sheets of peritoneum that connect organs to abdominal wall and to each other 1) mesentery proper - small intestine to posterior abdominal wall 2) mesocolon - large intestine to posterior abdominal wall 3) falciform ligament - liver to anterior abdominal wall 4) lesser omentum - stomach to liver 5) greater omentum - stomach to posterior abdominal wall 3. some organs are retroperitoneal (parts of intestines, pancreas, kidneys) - Tunics 1. mucosa a. epithelium 1) stratified squamous in mouth, esophagus, anal canal 2) simple columnar in stomach and intestines b. lamina propria 1) areolar connective tissue, lots of capillaries and lymphatic vessels, lymphatic nodules c. muscularis mucosae 1) thin layer of smooth muscle creates folds 2. submucosa a. areolar connective tissue, lots of vessels and nerve fibers 3. muscularis externa a. thicker layers of smooth muscle 1) circular, longitudinal layers 2) nerve fibers 4. serosa (visceral peritoneum) - intrinsic nerve plexuses (enteric nervous system) 1. network of nerves in digestive tract wall that regulate and coordinate (submucosal and myenteric) 2. influenced by extrinsic autonomic fibers • Mouth - Vestibule - area between teeth and lips - Oral cavity proper - area enclosed by teeth and gums - Palate 1. hard (maxillae and palatine bones) 2. soft (muscle) - Tongue 1. mixes food with saliva, sense of taste - Salivary glands 1. cleanse mouth and moisten food 2. begin digestion of carbohydrates 3. parotid, mandibular, sublingual • Pharynx - Oropharynx and laryngopharynx are food passageways • Esophagus - Food passageway - Deglutition (swallowing) accomplished by muscles in mouth, pharynx and esophagus - Submucosa contains mucus producing esophageal glands - Muscularis externa contains some skeletal muscle - Outer tunic c
More Less

Related notes for BIOB34H3

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.