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Digestive System Chapter 15. Tongue n Mostly muscle tissue –What type of muscle would it be? Frenulum – connects the tongue to the bottom of the mouth.

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Presentation on theme: "Digestive System Chapter 15. Tongue n Mostly muscle tissue –What type of muscle would it be? Frenulum – connects the tongue to the bottom of the mouth."— Presentation transcript:

1 Digestive System Chapter 15

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

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

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

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

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

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

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

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

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

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

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

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

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

15 Stomach n 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 – n 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 n 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  Storage area  What does it store?  Reabsorbs water to concentrate __________.  Hormones stimulate sphincter to relax, open duct  Causing what to happen? Gallbladder

23 Questions n If a person had a condition which limited their ability to produce hydrochloric acid in the stomach, how might this affect digestion and why? n If someone lost control of their pyloric sphincter and was unable to contract it, how would this affect digestion? n 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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