Digestive System

• Taking food


  Ingestion
• Breaking food into nutrient molecules

  Digestion
• Movement of nutrients into the bloodstream

  Absorption
• Excretes to rid the body of indigestible waste

  Defacation
• What are the two main groups of organs in the digestive system?

  Alimentary canal and Accessory digestive organs
• Organs responsible for ingestions, digestion, absorption, and defacation

  Alimentary canal
• Includes teeth, tongue, and several large digestive organs

  Accessory digestive organs
• Alimentary canal is also known as

  Gastrointestinal tract
• A continuous, coiled, hollow tube that runs though the ventral cavity from stomach to anus

  Alimentary canal
• Organs in alimentary canal:

  Mouth, Pharynx, Esophagus, Stomach, Small intestine, Large intestine, Anus
• A mucous membrane-lined cavity

  Mouth (Oral cavity)
• Protects the anterior opening

  Lips (Labia)
• Forms the lateral walls

  Cheeks
• Forms the anterior roof

  Hard palate
• Forms the posterior roof

  Soft palate
• Fleshy projection of the soft palate

  Uvula
• Space between lips externally and teeth and gums internally

  Vestibule
• Are contained by the teeth

  Oral cavity proper
• Attached at hyoid bone and styloid processes of the skull, and by the lingual frenulum to the floor of the mouth

  Tongue
• Tonsils: Located at the posterior end of oral cavity

  Palatine
• Tonsils: Located at the base of the tongue

  Lingual
• What is mastication?

  Chewing
• Contains the taste buds or taste receptors

  Papillae
• It serves as a passageway for food, fluids, and air

  Pharynx
• Pharynx: Posterior to oral cavity

  Oropharynx
• Pharynx: Below the oropharynx and continuous with the esophagus

  Laryngipharynx
• Skeletal muscles responsible for propelling food to the esophagus

  Longitudinal outer layer and circular inner layer
• Alternating contractions of the muscle layers

  Peristalsis
• Length of esophagus

  10 inches
• It conducts food by peristalsis to the stomach

  Esophagus
• Four layers from innermost to outermost, from esophagus to the large intestine

  Mucosa, Submucosa, Muscularis externa, Serosa
• The innermost, moist membrane consisting of surface epithelium that is mostly simple columnar epithelium (except for esophagus—stratified squamous epithelium); Small amount of connective tissue (lamina propria); Scanty smooth muscle layer

  Mucosa
• Mucosa lines the cavity known as?

  Lumen
• This layer is just beneath the mucosa. It is a soft connective tissue with blood vessels, nerve endings, mucosa-associated lymphoid tissue, and lymphatic vessels

  Submucosa
• A layer of smooth muscle. Inner circular layer and outer longitudinal layer.

  Muscularis externa
• Outermost layer of the wall; contains fluid-producing cells

  Serosa
• It is the innermost layer that is continuous with the outermost layer.

  Visceral peritoneum
• Outermost layer that lines the abdominopelvic cavity by the way of mesentery

  Parietal peritoneum
• Two intrinsic nerve plexuses in the Alimentary canal wall

  Submucosal nerve plexus and myenteric nerve plexus
• It regulates mobility and secretory activity of the GI tract organs

  Alimentary canal nerve plexuses