1. Transport Systems Digestive

2. Function The nourishment of the body’s cells is dependant on the relationship between the digestive system and the cardiovascular system. The nourishment of the body’s cells is dependant on the relationship between the digestive system and the cardiovascular system. The Digestive system is specialized to ingest, propel, digest, and absorb food. The Digestive system is specialized to ingest, propel, digest, and absorb food.

3. Oral Cavity Lips/Labia: muscular folds covered by mucosa (internally) and stratified squamous (externally). Lips/Labia: muscular folds covered by mucosa (internally) and stratified squamous (externally). Cheeks: Internally-moist stratified squamous and exteriorly – skin. (inside the cheek is the buccinator muscle and the buccal fat pad. Cheeks: Internally-moist stratified squamous and exteriorly – skin. (inside the cheek is the buccinator muscle and the buccal fat pad. Tongue: attached posteriorly in the oral cavity proper. Anchored inferiorly by the frenulum. Intrinsic muscles are within the tongue and extrinsic muscles are outside the tongue but attached. There is a groove around the center (terminal sulcus). Anterior to the terminal sulcus covered by papillae some of which have taste buds. Posterior no papillae but few taste buds – lots of lymphoid tissue (lingual tonsils). Tongue: attached posteriorly in the oral cavity proper. Anchored inferiorly by the frenulum. Intrinsic muscles are within the tongue and extrinsic muscles are outside the tongue but attached. There is a groove around the center (terminal sulcus). Anterior to the terminal sulcus covered by papillae some of which have taste buds. Posterior no papillae but few taste buds – lots of lymphoid tissue (lingual tonsils).

4. Oral Cavity Continued... Teeth – (32 in adult) 2 dental arches (maxillary and mandibular) divided into 4 quadrants (LU, RU, LL, RL). Each quadrant has 1 central and 1 lateral incisor, 1 canine, 1 st and 2 nd premolars or bicuspids, and 1 st, 2 nd, and 3 rd molars (wisdom teeth). Teeth – (32 in adult) 2 dental arches (maxillary and mandibular) divided into 4 quadrants (LU, RU, LL, RL). Each quadrant has 1 central and 1 lateral incisor, 1 canine, 1 st and 2 nd premolars or bicuspids, and 1 st, 2 nd, and 3 rd molars (wisdom teeth). Permanent (2ndary teeth) –adult Permanent (2ndary teeth) –adult Deciduous (Primary teeth)- children Deciduous (Primary teeth)- children They are set in alveoli along ridges of the mandible and maxilla covered by dense connective tissue and stratified squamous epithelia (gingiva). They are set in alveoli along ridges of the mandible and maxilla covered by dense connective tissue and stratified squamous epithelia (gingiva).

5. Oral Cavity Continued... Muscles of Mastication: Temporalis, masseter, medial pterygoid, lateral pterygoid Muscles of Mastication: Temporalis, masseter, medial pterygoid, lateral pterygoid Palate/Palatine Tonsils: Palate/Palatine Tonsils: Hard palate: bony part; anterior. Hard palate: bony part; anterior. Soft Palate: skeletal muscle and connective tissue- uvula attached. Soft Palate: skeletal muscle and connective tissue- uvula attached. Tonsils: Lateral wall of fauces Tonsils: Lateral wall of fauces

6. Small Tubular Glands: Small Tubular Glands: lingual glands (within tongue) lingual glands (within tongue) palatine glands (in palate) palatine glands (in palate) buccal glands (in cheeks) buccal glands (in cheeks) labial glands (in lips) labial glands (in lips) Salivary Glands: 3 pairs of large multi-cellular glands: Salivary Glands: 3 pairs of large multi-cellular glands: Parotid: Behind ear Parotid: Behind ear Submandibular: below mandible Submandibular: below mandible Sublingual: Below tongue Sublingual: Below tongue

7. All major salivary glands are compound alveolar glands. All major salivary glands are compound alveolar glands. Alveolar glands secrete serous and mucous secretions (saliva). Alveolar glands secrete serous and mucous secretions (saliva).

8. Upper Alimentary Canal Oropharynx follows the oral cavity and leads to the laryngopharynx. This leads to the esophagus which is accompanied by mucous glands. Oropharynx follows the oral cavity and leads to the laryngopharynx. This leads to the esophagus which is accompanied by mucous glands. The esophagus extends between the pharynx and the stomach. It lies in the mediastinum. The esophagus passes through the esophageal hiatus (diaphragm). It is lined with all four tunics of tissue and is topped by the upper esophageal sphincter and is terminated at the lower esophageal sphincter. The esophagus extends between the pharynx and the stomach. It lies in the mediastinum. The esophagus passes through the esophageal hiatus (diaphragm). It is lined with all four tunics of tissue and is topped by the upper esophageal sphincter and is terminated at the lower esophageal sphincter.

9. Stomach All four tunics of tissue. 3 layers of smooth muscle for mixing. All four tunics of tissue. 3 layers of smooth muscle for mixing. Regions: cardiac, fundus, body, greater and lesser curvature, and the pyloric. Regions: cardiac, fundus, body, greater and lesser curvature, and the pyloric. Opening to the duodenum of the small intestine is the pyloric sphincter. Opening to the duodenum of the small intestine is the pyloric sphincter. Rugae allow for change in stomach volume. Rugae allow for change in stomach volume. Gastric pits: Gastric pits: Parietal cells: Parietal cells: Chief cells: Chief cells: Mucous neck cells: Mucous neck cells: Endocrine cells: Endocrine cells:

10. Small Intestine Duodenum: 180 degree turn. Short segment that receives secretions from the gallbladder and pancreas. Duodenum: 180 degree turn. Short segment that receives secretions from the gallbladder and pancreas. Jejunum: Gradual decrease in the diameter of the small intestine due to and increase in villi and microvilli. Jejunum: Gradual decrease in the diameter of the small intestine due to and increase in villi and microvilli. Ileum: Lots of villi and microvilli. Terminates at the Cecum with the ileocecal sphincter. Ileum: Lots of villi and microvilli. Terminates at the Cecum with the ileocecal sphincter.

11. Large Intestine The cecum is the proximal end of the large intestine that extends inferiorly to form the appendix (lymphatic tissue). The cecum is the proximal end of the large intestine that extends inferiorly to form the appendix (lymphatic tissue). Colons: Ascending, Transverse, Decending, and Sigmoid. Colons: Ascending, Transverse, Decending, and Sigmoid. Rectum is at the terminus of the Sigmoid colon. It has a very thick muscular tunic and it terminates at the superior end of the anal canal. Rectum is at the terminus of the Sigmoid colon. It has a very thick muscular tunic and it terminates at the superior end of the anal canal. Anal Canal: Internal anal sphincter (smooth muscle) and external anal sphincter (skeletal muscle). End of anal canal turns from simple columnar epithelium to stratified squamous. Anal Canal: Internal anal sphincter (smooth muscle) and external anal sphincter (skeletal muscle). End of anal canal turns from simple columnar epithelium to stratified squamous.

12. Histology of the Alimentary Canal Mucosa: the inner most tunic composed of 3 layers. Mucosa: the inner most tunic composed of 3 layers. 1. Mucous epithelium – moist stratified squamous epithelium (mouth, oropharynx, esophagus, and anal canal) and simple columnar in the remainder of the tract. 2. Lamina Propria – loose connective tissue 3. Muscluaris mucosae – thin smooth muscle layer.

13. Histology of the Alimentary Canal Submucosa: thick connective tissue layer containing nerves, blood vessels, and small glands. Nerves form submucosal plexus (parasympathetic). Submucosa: thick connective tissue layer containing nerves, blood vessels, and small glands. Nerves form submucosal plexus (parasympathetic). Muscularis: the 3 rd layer made of an inner layer of circular smooth muscle and an outer layer of longitudinal muscle. A nerve plexus – myenteric lies between the 2 muscle layers with the submucosal called the intramural. Muscularis: the 3 rd layer made of an inner layer of circular smooth muscle and an outer layer of longitudinal muscle. A nerve plexus – myenteric lies between the 2 muscle layers with the submucosal called the intramural. Serosa – Outer most layer of connective tissue which connects with visceral peritoneum. Serosa – Outer most layer of connective tissue which connects with visceral peritoneum.

14. General Physiology Ingestion: food into the oral cavity Ingestion: food into the oral cavity Mastication: (chewing) performed by the teeth. Increases surface area of the food bolus – assists in the breakdown by enzymes. Mastication: (chewing) performed by the teeth. Increases surface area of the food bolus – assists in the breakdown by enzymes. Propulsion: movement of food through the alimentary canal (24-36 hours to make it through the length of the tract). Each part of the digestive tract aids in moving the bolus (food ball). Propulsion: movement of food through the alimentary canal (24-36 hours to make it through the length of the tract). Each part of the digestive tract aids in moving the bolus (food ball).

15. General Physiology Deglutition (swallowing): move food from oral cavity into the esophagus. Deglutition (swallowing): move food from oral cavity into the esophagus. Peristalsis: moves it the rest of the way through wave-like contractions in the smooth muscle tissue. Peristalsis: moves it the rest of the way through wave-like contractions in the smooth muscle tissue. Mixing: occurs between the bolus and secreted enzymes. Segmental contractions are mixing contractions. Mixing: occurs between the bolus and secreted enzymes. Segmental contractions are mixing contractions.