Digestive System

• Churning snd movement of food through Gl tract.


  Mixing and propulsion
• Ingestion is taking food into mouth.
• Secretion each day,cells within the walls of the Gl tract and accessory digestive organs secrete a total of about 7 liters of water,acid, buffers, and enzymes into lumen of the tract.
• Motility alternating contractions and relaxation of smooth in the walls of the Gl tract mix food and secretions and move them towards the anus.
• Absorption is the movement of the products of digestions from the lumen of the Gl tract into blood or lymph.
• Defecation involves elimination of undigested material from the body
• Digestion is the process of breaking down ingested food into molecules that can be used by body cells.
• The eliminated material is termed feces or stool.
• The mouth is also referred to as the oral or buccal cavity,is formed by the cheeks,hard palate and soft palate and tongue.
• The cheeks form the lateral walls of the oral cavity,They covered externally by skin and internally by mucous membrane,which consists non-keratinized stratified squamous epithelium.
• Hard Palate - The hard palate forms the roof of the oral cavity. It is composed of bone (palatine bones) and covered with keratinized stratified squamous epithelium.
• Soft Palate - The soft palate forms the posterior part of the roof of the oral cavity. It is muscular and covered with non-keratinized stratified squamous epithelium.
• Tongue - The tongue is a muscular organ located at the floor of the oral cavity. It is covered with non-keratinized stratified squamous epithelium.
• Teeth are specialized structures found on the upper and lower jaws. They consist of enamel, dentin, cementum, and dental pulp.
• Enamel - Enamel is the outermost layer of teeth and is the hardest substance in the human body. It covers the crown of the tooth and provides protection against wear and tear.
• Teeth are used for biting, chewing, tearing, crushing, grinding, cutting, and manipulating food.
• Saliva contains enzymes such as amylase which begin the digestion of carbohydrates.
• Cementum - Cementum is a thin layer of tissue that attaches the root of the tooth to the jawbone.
• Dentin - Dentin makes up most of the tooth structure and supports the enamel. It contains tubules through which nerves can be stimulated when exposed to hot or cold temperatures.
• Mastication involves breaking down food into smaller pieces using the teeth.
• Dental Pulp - Dental pulp is the innermost layer of the tooth and contains blood vessels, nerve fibers, and connective tissue cells. It nourishes the tooth and transmits sensation to the brain.
• The cheeks form the lateral walls of the oral cavity.
• The palate forms the roof of the mouth and separates it from the nasal cavity.
• Buccinator muscles and connective tissue lie between the skin and mucous membranes of the cheeks.
• The lips are fleshly folds surrounding the opening of the mouth.
• Lips contain smooth muscle that allows them to move and close off the mouth during swallowing or speech.
• Salivary glands secrete saliva into the oral cavity through ducts.
• Lips is contain the orbicularis oris and are covered externally by skin and externally by a mucous membranes.
• The internal surface of each lip is attached to its corresponding gum by a midline fold of mucous membrane called Labial frenulum
• The oral vestibule of the oral cavity is the space bounded externally by the cheeks and lips internally by the gums and teeth.
• The oral cavity proper is the spaces that extends from gum and teeth to the fauces ,the opening between the oral cavity and oropharynx.
• The soft palate is made up of muscles and connective tissue and it forms the posterior part of the roof of the oral cavity.
• The hard palate is formed by the maxillae,palatine bones,and vomer bone
• The uvula is a small finger-like projection at the back end of the soft palate.
• The soft palate is form the posterior portion of the roof of the mouth, is an arch muscular partition between the oropharynx and nasopharynx that is lined with mucous membranes.
• The dorsal surface of the tongue is covered by stratified squamous epithelium which contains numerous taste buds.
• The tongue is a muscular organ located in the floor of the oral cavity.
• Anteriorly,the Palato glossal arch extends to the side of the base of the tongue, posteriorly,the palato pharyngeal arch extends to side of pharynx.
• The tongue is an accessory digestive organ composed of skeletal muscle covered with mucous membrane.
• The extrinsic muscles of the tongue,which originate outside the tongue and insert into connective tissues in the tongue