PowerPoint Presentation to accompany Hole’s Human Anatomy and Physiology, 9/e by Shier, Butler, and Lewis

UNIT FIVE

Chapter 17 Digestive System

Alimentary Canal Mucosa surface epithelium with underlying connective tissue and small amount of smooth muscle contains glands, including mucus glands carries on secretion and absorption

Alimentary Canal Figure 17.1 Submucosa loose connective tissue with glands, blood and lymphatic vessels, and nerves Figure 17.1

Alimentary Canal Muscular layer Serosa or serous layer two layers of smooth muscle circular fibers compose inner coat longitudinal fibers compose outer coat Serosa or serous layer visceral peritoneum epithelium on the outside and connective tissue beneath, secretes serous fluid

Figure 17.3

Movement of the Tube Figure 17.4 Mixing movements Propelling movements smooth muscles contract rhythmically mix food with digestive juices Propelling movements wavelike movements called peristalsis receptive relaxation occurs ahead of peristalsis Figure 17.4

Innervation of the Tube Parasympathetic impulses increase digestive system activities Sympathetic impulses decrease digestive system activities Submucosal plexus controls secretion by the GI tract Myenteric plexus muscular layer, controls motility

Mouth Figure 17.5 Cheeks Lips Tongue muscles of expression and chewing contain skeletal muscles and sensory receptors Tongue tongue muscles mix food taste buds provide sensation lingual tonsils are lymphatic tissue at the root of the tongue Figure 17.5

Figure 17.6

Palate Figure 17.7 Roof of the oral cavity hard palate is anterior soft palate is posterior and ends in the uvula Figure 17.7

Palate Figure 17.7 Palatine tonsils Pharyngeal tonsils (adenoids) located in the back of the throat Pharyngeal tonsils (adenoids) located above the soft palate Figure 17.7

Teeth Figure 17.9 Primary or deciduous teeth 20 teeth, erupt between 6 months and 4 years Secondary or permanent teeth 32 teeth, erupt between 6 and 25 years of age incisors, cuspids, bicuspids, molars Teeth break food into small pieces Figure 17.9

Teeth Crown projects out from the gum covered with enamel Figure 17.10

Teeth Root Dentin anchored to the jaw by the periodontal ligament covered with cementum Dentin living tissue similar to bone, but harder surrounds the pulp cavity which contains nerves and blood vessels

Saliva Saliva moistens food Saliva contains bicarbonate ions that buffer acids in the mouth Two types of secretory cells serous cells secrete a watery fluid contains amylase, an enzyme that splits starch and glycogen into disaccharides mucous cells secrete a thick fluid, mucus, that binds and lubricates

Salivary Glands parotid glands submandibular glands sublingual glands largest, secrete watery fluid rich in amylase submandibular glands secrete a viscous fluid sublingual glands smallest, secrete thick mucus fluid Innervation sympathetic impulses stimulate a small amount of viscous secretion parasympathetic impulses stimulate a large volume of watery saliva

Figure 17.11

Pharynx Nasopharynx Oropharynx Laryngopharynx communicates with the nasal cavity, air passage Oropharynx posterior to the mouth, passage for food and air Laryngopharynx inferior to the oropharynx, leads to esophagus