ex. 38 [digestive system]

• digestive system provides body with nutrients, water, and electrolytes essential for health
• alimentary canal wall consists of mucosa, submucosa, muscularis externa, and serosa
• alimentary canal wall

  A) mucosa

  B) submucosa

  C) muscularis externa

  D) serosa

  E) lumen

  F) lamina propria

  G) muscularis mucosae

  H) circular layer

  I) longitudinal layer

  
• alimentary canal organs and subdivisions

  A) mouth (oral cavity)

  B) tongue

  C) parotid gland

  D) sublingual gland

  E) submandibular gland

  F) esophagus

  G) stomach

  H) small intestine

  I) duodenum

  J) jejunum

  K) ileum

  L) large intestine

  M) transverse colon

  N) descending colon

  O) ascending colon

  P) cecum

  Q) sigmoid colon

  R) rectum

  S) appendix

  T) anal canal

  U) anus

  
• mouth: the opening of the digestive system that allows food to enter the body
• pharynx: common passage way for food, fluid and air
• esophagus: food passageway that conducts food to stomach in wavelike peristaltic motion; no digestive or absorptive function
• stomach: temporary storage region for food as well as site for mechanical and chemical breakdown of food
• most digestive activity occurs in pyloric part of stomach
• small intestine: nearly all nutrient absorption occurs here
• large intestine: consolidate and propel waste to be eliminated - provides site where intestinal bacteria manufacture vitamin b and k and reclaims most of remaining water
• stomach has a third layer in its smooth muscle of muscularis externa layer that is arranged obliquely to churn, mix and pummel food
• gastric glands in mucosa secrete hydrochloric acid and hydrolytic enzymes
• chief cells produce pepsinogen which is converted to pepsin by the intrinsic factor
• parietal cells secrete HCl and intrinsic factor
• microvilli: microscopic projections of surface plasma membrane of mucosal epithelial cell
• villi: fingerlike projections of mucosa tunic
• circular folds: deep folds of mucosa and submucosa that force chyme to spiral through intestine, mixing it and slowing progess
• teeth: contribute to mechanical breakdown/digestion
• salivary glands: secrete saliva into oral cavity; contains amylase (starch digestion)
• parotid gland: mainly serous
• submandibular gland: mucin and serous
• sublingual gland: mostly mucin
• saliva consists of mucins which moistens food and serous fluid called amylase which starts starch digestion
• liver: produce bile
• pancreas: produces enzymes and an alkaline fluid secreted into duodenum
• molar cross section

  A) crown

  B) neck

  C) root

  D) enamel

  E) gingiva

  F) dentin

  G) pulp

  H) cement

  I) root canal

  J) periodontal ligament

  K) apical foramen

  
• incisor teeth are used to cut food
• canines are used to tear meat
• pre molars are used to grind food
• posterior molars are used to crush food
• cement: material covering tooth root
• crown: visible portion of tooth
• dentin: forms major portion of tooth structure; similar to bone
• enamel: hardest substance in body
• gingiva sulcus: narrow gap between crown and gum
• odontoblast: produces dentin
• periodontal ligament: attaches tooth to tooth socket
• pulp: sit of blood vessels, nerves, and lymphatics
• root canal: space within root that contains pulp