1. What is/are the function(s) of the digestive system? What structures are necessary? How does function vary with form? Introduction to Digestive System

2. Graphic overview of alimentary canal How are we similar to a tall donut? Introduction to Digestive System

3. How does this system develop embryologically? Endoderm is the epithelial lining of the alimentary canal. Mesoderm splits into somatic and splanchnic mesoderm. Splanchnic mesoderm contributes to substance of G.I. Viscera (visceral and parietal peritoneum). Yolk or membrane connection is the midgut Anterior = foregut and posterior = hindgut. Introduction to Digestive System

4. What are features of the mouth and oral cavity? Oropharyngeal cavity in jawed fishes Oral cavity in tetrapod What comprises the cavity? Laterally… the cheeks (mucousa, buccinator, hypodermis, dermis, and epidermis) Superiorly… the palate (primary and secondary) Oral Cavity

5. What are features of the mouth and oral cavity? Reptiles have palatal fissure, this channels air from internal nares to pharynx. Anurans can have openings that lead to evaginations of the oral cavity (vocal sacs) extending below the phayrnx. Seed eating birds can have a similar evagination (seed pouch) suspended by the mylohyoid. Granivorous mammals can have cheek pouches http://content.answers.com/main/content/wp/en/thumb/7/7d/240px-Litoria_chloris_calling.jpg http://www.birdandhike.com/Wildlife/Mamm/06Rod/04_Het/Dip_mer/D_mer.htm

6. Hard and Soft palates Cleft lip/palate: congenital defect where embryonic tissues fail to fuse What can your palate do for you? Oral Cavity

7. Tongue

10. What are the functions of the tongue? Assist in forming a bolus Facilitate taste Used to capture food Used to thermoregulate Cleaning body (fur, eyelids etc.) Bound by the frenulum Receptors for stereognosis

11. What are the functions of the oral glands of tetrapods? Assist in forming a bolus Facilitate taste Can make tongue sticky Can produce toxins (palatal in 4 snake groups, sublingual in lizard) Initiate digestion (amylase/ptyalin) Aid in immunity (lysozyme) Goblet cells in fish… papa catfishes Oral Glands

12. 3 paired glands: Parotid Submandibular Sublingual Scattered small tubular glands How do you salivate? Secrete mucus, serous fluid and enzymes Endocrine or Exocrine? Oral Glands