Oral CavityOral Cavity Chemical digestion - Saliva Chemical digestion - Saliva

contains enzyme (amylase -> contains enzyme (amylase -> Carbohydrates).Carbohydrates).

Mechanical digestion – teethMechanical digestion – teeth Tongue – muscular organ; aid in Tongue – muscular organ; aid in

swallowingswallowing Stratified Squamous epithelial Stratified Squamous epithelial

cells – function of protection.cells – function of protection. ““Bolus” -= foodBolus” -= food Pushed into PharynxPushed into Pharynx

EsophagusEsophagus Bolus is pushed down via swallowing.Bolus is pushed down via swallowing. Epiglottis covers trachea, allows Epiglottis covers trachea, allows

movement of food down muscular movement of food down muscular tube.tube.

2 Layers: Circular (Horizontal) & 2 Layers: Circular (Horizontal) & Longitudinal (Vertical)Longitudinal (Vertical) Circular – made of smooth muscle tissueCircular – made of smooth muscle tissue Longitudinal - made of smooth muscle Longitudinal - made of smooth muscle

tissuetissue When one muscle layer contracts the When one muscle layer contracts the

other relaxes.other relaxes. Involuntary contraction and relaxation.Involuntary contraction and relaxation.

StomachStomach Made up of epithelial cells and gastric Made up of epithelial cells and gastric

glandsglands Cells: Mucous (mucous), Parietal (HCl), Cells: Mucous (mucous), Parietal (HCl),

& Chief (pepsinogen = inactive enzyme)& Chief (pepsinogen = inactive enzyme) Pepsin = Active enzyme that digests Pepsin = Active enzyme that digests

proteins.proteins. Stomach cells go through mitosis rapidly Stomach cells go through mitosis rapidly

(every 3 days new cells)(every 3 days new cells) Regulated by hormone gastrinRegulated by hormone gastrin Chemically and mechanically digested – Chemically and mechanically digested –

stomach contractions also (smooth stomach contractions also (smooth muscle cells)muscle cells)

Small IntestinesSmall Intestines Acid chyme needs to be further digested.Acid chyme needs to be further digested. Liver – produces bile. Bile aids in the Liver – produces bile. Bile aids in the

emulsification / digestion of fats.emulsification / digestion of fats. Gall bladder stores bile.Gall bladder stores bile. Pancreas – bicarbonate ions aid in acid Pancreas – bicarbonate ions aid in acid

neutralizationneutralization Duodenum – acid chyme squirted into small Duodenum – acid chyme squirted into small

intestine and mixed with bile.intestine and mixed with bile. Tissues = smooth muscle tissue (involuntary)Tissues = smooth muscle tissue (involuntary) Simple squamous = blood absorbs nutrients Simple squamous = blood absorbs nutrients

and transportsand transports Villi & microvilli aid in absorption of nutrientsVilli & microvilli aid in absorption of nutrients Nutrients diffuse via epithelial cells into Nutrients diffuse via epithelial cells into

capillaries.capillaries.

Large IntestinesLarge Intestines 2 Cell Types – Simple columnar and 2 Cell Types – Simple columnar and

smooth muscle cellssmooth muscle cells Appendix – found adjacent to cecum, Appendix – found adjacent to cecum,

minor contribution to immune system.minor contribution to immune system. E.coli found in lg intestine – aids in E.coli found in lg intestine – aids in

vitamin production.vitamin production. Rectum – stores feces (indigestible Rectum – stores feces (indigestible

plant fiber and prokaryotes); voluntary plant fiber and prokaryotes); voluntary and involuntaryand involuntary

Water is reabsorbed (too much or too Water is reabsorbed (too much or too little = diarherra or constipation)little = diarherra or constipation)