BIOL 2030 Human Anatomy & Physiology II Why do we have a digestive system? Provide nutrients to all tissues in the body What is digestion? Breakdown of organic molecules/nutrients... mechanical and chemical What tasks does your digestive system do? Ingestion, mastication, propulsion, mixing, secretion, digestion, absorption, transportation, elimination

Oral cavity Pharynx Esophagus Stomach Small intestines Pancreas Liver Large intestines Rectum Anus Organ Function Time ingestion/mastication sec. secretion/mixing/digestion transportation 1-2 sec. transportation/propulsion 5-8 sec. digestion/secretion 3-4 hrs. mixing digestion/secretion/mixing 3-5 hrs. absorption/propulsion absorption/propulsion hrs. elimination What happens between my mouth and anus? See Table 24.1

Graphic overview of alimentary canal What structures exist between mouth and anus?

Graphic overview of … What is the oral cavity and what does it do?

Ingestion (alternate routes) Mastication = chewing Which type of digestion? Why? Accomplished via: cheeks, lips, tongue, teeth, jaws Vestibule: space between cheeks, lips and gums Oral cavity proper: space within floor of mouth and roof (palate) Types of teeth: Incisors Canines Premolars Molars deciduous permanent What is the oral cavity and what does it do?

Teeth embedded in: Alveoli in the Maxilla (upper jaw) & Mandible (lower jaw) Closing jaw = masseter temporalis medial pterygoids Opening jaw = lateral pterygoids How do you masticate?

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

Hard and Soft palates Cleft lip/palate: congenital defect where embryonic tissues fail to fuse “Because I was different” by Don Bartlette What can your palate do for you ?

Food formed into a bolus Pushed against hard palate by tongue Initiates swallowing reflex Pharyngeal muscles aid in pushing into esophagus Swallowing (deglutition) divided into 3 phases: 1) voluntary 2) pharyngeal 3) esophageal Which of the pharynxes usually conduct food? How does food get from oral cavity to esophagus?

Conducting Tube ~ 12” in length 2 sphincters: upper esophageal lower esophageal or cardiac Generalized layers of alimentary canal What is the role of the esophagus?

Nerve plexus allows local reflexes to be integrated independent of the CNS. Sensory neurons Motor neurons Interneurons What is the role of the enteric plexus?