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Digestive System

Digestive System. Chapter 15. Tongue. Mostly muscle tissue What type of muscle would it be? Frenulum – connects the tongue to the bottom of the mouth What is the purpose of the tongue? Papillae – rough projections that contain taste buds Why would these be rough?

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Digestive System

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  1. Digestive System Chapter 15

  2. Tongue • Mostly muscle tissue • What type of muscle would it be? • Frenulum – connects the tongue to the bottom of the mouth • What is the purpose of the tongue? • Papillae – rough projections that contain taste buds • Why would these be rough? • Four types of taste buds – sweet, sour, salt, bitter

  3. Palate • 2 sections • Hard Palate • Also known as the maxilla • Anterior Portion • Soft Palate • Posterior Portion • This and the uvula are drawn up during swallowing • Why is this important? • Blocks off the nasal passage during swallowing

  4. Tonsils • Lingual – at the base of the tongue • Used as anchor, covered by lymphatic tissue • Palatine – Located on the side of the tongue • Which do you think is removed when you have tonsillitis? • Palatine – exposed to many pathogens so they can easily become infected.

  5. Teeth • 2 sets • Primary (baby) – 10 on each jaw • What happens to these? • They are lost • The roots are resorbed and teeth are pushed out by secondary teeth • Secondary (permanent) – 16 on each jaw • Begin to appear around age six

  6. Secondary Teeth • Incisors – total of eight, front teeth • Function? • Tearing off bites • Cuspids (Canine) – total of four, sharper teeth (fangs) • Function? • Rip and Tear tough food.

  7. Secondary Teeth • Bicuspids (premolar) – total of eight, behind cuspids, a bit flatter • Function? • Mash and grind, little bit of tearing • Molars – total of 12, back teeth much flatter (4 first, 4 Second, 4 Third) • Third also known as wisdom teeth • Function? • Mash and Grind • Why do we need so many types of teeth?

  8. Tooth Structure • Based on the name where do you think each part is? • Crown – • Root – • Enamel – • Hardest substance in the body and cannot be replaced • What problem does this pose? • Dentin – deep to the enamel and surrounds the pulp cavity (nutrient supply)

  9. Salivary Glands • Main Secretions • Amylase – breaks down large starch and glycogen molecules • Mucus – • What is its purpose? • Bind food particles and lubricate alimentary canal • What triggers secretions? • Parasympathetic nervous system

  10. Salivary Glands – 3 different glands • Paratid – Located anterior and inferior to the ear • Secretes saliva rich in amylase • Submandibular – Located where? • Secretes thicker saliva than paratid. • Why thicker? • Sublingual – Located where? • Secretes primarily mucus

  11. Pharynx • Connects nasal and oral cavities with the esophagus • Contains the epiglottis • What is this? • Flaplike structure used to seal off trachea during swallowing. • Has three sections • - nasopharynx attaches nasal cavity • - oropharynx attaches mouth • - laryngopharynx attaches esophagus

  12. Wall Structure • 4 layers • Mucosa – • Submucosa – • Muscular layer - • Serosa –

  13. Esophagus • Connects pharynx to stomach • Function - • Ends at lower esophageal sphincter • What is a sphincter? • This one connects the stomach and the esophagus, what will its function be?

  14. Stomach • Location – • Size is small when empty, yet it can hold one liter. How? • What happens in the stomach?

  15. Stomach • Regions of the stomach • Cardiac - posterior to lower esophageal sphincter • Function- • Fundic – Most anterior portion • Function – • Body – Main region • Function – • Pyloric – most posterior region • Function – • Stomach ends at Pyloric Sphincter

  16. Gastric Juice • 4 Components • Pepsin – • Pepsinogen – • Hydrochloric Acid – • Mucus

  17. Gastric Regulation • Produced regularly, but rate can vary • What might cause it to vary? • Gastrin – • What stimulates the release?

  18. Gastric Mixing • How will the stomach perform its functions? • Chyme – • Where does food go to exit stomach? • How does the stomach move it there?

  19. Pancreas • Located near posterior abdominal wall inferior to stomach • Secretes____ into the ___. • Amylase • Lipase • Nuclease • What other important function?

  20. Liver • Located… • Lobed • Multiple Functions • Blood – • Storage - • Digestive functions • Metabolism of Carbohydrates, Lipids and Proteins • Secretes ____ through the ___into the ____.

  21. Bile • Consists of: • 1. • Two types biliverdin and bilirubin • 2. • Only part of the bile that has digestive function • Emulsification • 3.

  22. Gallbladder • Storage area • What does it store? • Reabsorbs water to concentrate __________. • Hormones stimulate sphincter to relax, open duct • Causing what to happen?

  23. Questions • If a person had a condition which limited their ability to produce hydrochloric acid in the stomach, how might this affect digestion and why? • If someone lost control of their pyloric sphincter and was unable to contract it, how would this affect digestion? • Thinking about the contents of the stomach, what might happen to a person with a lower esophageal sphincter that does not contract completely?

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