Digestive System

A. the gastrointestinal tract
b. accessory digestive organs

A. Oral cavity: mouth and pharynx b. esophagus c. stomach d. small intestine e. large intestine

A. duodenum b. jejunum c. ileum

A. appendix b. colon c. rectum d. cecum

A. salivary glands b. exocrine pancreas c. biliary system: liver and gallbladder

Is continuous with the external environment (mouth to anus) and is thus considered outside the body proper

A. pH in stomach can be as low as 2: compared to pH of body ~6.8 to 8
b. digestive enzymes must be activated in the lumen as they are designed to destroy tissue
c. home of microorganisms
d. foodstuffs are complex foreign particles, which in the body proper would activate the immune system

A. mucosa
b. submucosa
c. muscularis externa
d. serosa

A. mucous membrane
b. lamina propria
c. muscularis mucosa - thin layer of smooth muscle

A. protective surface
b. exocrine gland cells for secretion of digestive juices
c. endocrine gland cells for secretion of blood-borne hormones
d. epithelial cells specialized for absorption

Thin layer of connective tissue that houses gut-associated lymphoid tissue ( protects against bacteria)

A. highly folded to increase surface area for absorption
b. degree of folding is dependent on function of the area
c. pattern of folding can be modified by contraction of the muscularis mucosa

A. submucosa
b. muscularis externa
c. serosa

A. thick layer of connective tissue that provides elasticity and distensibility
b. contains the larger blood and lymph vessels and nerve network (submucusal plexus)

A. consists of two layers 1. concentric inner layer - responsible for contraction 2. longitudinal outer layer - shortens the tube
b. also possesses a nerve network called myentric plexus