PowerPoint Presentation to accompany Holes Human Anatomy and Physiology, 9/e by Shier, Butler, and...
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Transcript of PowerPoint Presentation to accompany Holes Human Anatomy and Physiology, 9/e by Shier, Butler, and...
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
• Submucosa– loose connective
tissue with glands, blood and lymphatic vessels, and nerves
Figure 17.1
Alimentary Canal• Muscular 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• Mixing 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• Cheeks
– muscles of expression and chewing
• Lips– 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• Roof of the oral
cavity– hard palate is anterior– soft palate is posterior
and ends in the uvula
Figure 17.7
Palate
• Palatine tonsils– located in the back of
the throat
• Pharyngeal tonsils (adenoids)– located above the soft
palate
Figure 17.7
Teeth• 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
– 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
– 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– 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