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:
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 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
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
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.
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
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.
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?
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)
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
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
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
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?
Stomach n Location – n Size is small when empty, yet it can hold one liter. How? n What happens in the stomach?
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
Gastric Regulation Produced regularly, but rate can vary What might cause it to vary? Gastrin – What stimulates the release?
Gastric Mixing How will the stomach perform its functions? Chyme – Where does food go to exit stomach? –How does the stomach move it there?
Pancreas Located near posterior abdominal wall inferior to stomach Secretes____ into the ___. Amylase Lipase Nuclease n What other important function?
Liver Located … Lobed Multiple Functions Blood – Storage - Digestive functions Metabolism of Carbohydrates, Lipids and Proteins Secretes ____ through the ___into the ____.
Bile Consists of: 1. Two types biliverdin and bilirubin 2. Only part of the bile that has digestive function Emulsification 3.
Storage area What does it store? Reabsorbs water to concentrate __________. Hormones stimulate sphincter to relax, open duct Causing what to happen? Gallbladder
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?