Digestive System

Digestive System

Chapter 38

• Parts of the system:• Mouth, pharynx, esophagus, stomach, small

intestine, Large intestine• Accessory organs:• Salivary glands, pancreas, liver

• Mouth:• Teeth tears food into small bits and helps to

mix saliva with the food• Salvia from the salivary glands contain

enzymes to begin the digestive process• Tongue will shape the food into a ball called a

bolus, it’s now ready for swallowing

• Esophagus: also called the food tube• Peristalsis- muscle contractions that move

food to the stomach

• Stomach: a sac that mixes food with enzymes and acids. Food is no longer a bolus, now called a chyme. A little bit of digestion

• Cardiac sphincter- a round muscle found at the top of the stomach. Controls the flow of food into the stomach

• Pyloric sphincter: found at the end of the stomach. Controls the flow of food out of the stomach

• Small Intestines 3 parts• Duodenum, jejunum, ileum• Most digestion occurs here

• Villi- small fingerlike projections– Increase the amount of surface that food passes

over– Villi contains blood vessels. Nutrients pass via

diffusion from intestines to blood• Travels thru the body and nutrients diffuse out

into cells that need the nutrients

• Accessory organs(no food goes thru them, but they aid in digestion)– Pancreas: produces sodium bicarbonate to reduce

the acid from the stomach. Also produces insulin which regulates blood sugar

– Liver: makes bile which breaks down fat. Bile is stored in the gall bladder

• Appendix- found on the lower right side. It is where the large and small intestines meet. May have once helped to break down cellulose

• Large Intestines (colon)• Parts of: Ascending, transverse, descending,

sigmoid, rectum, anus• This is where e.coli resides. It feeds on

undigested food and releases vit. K• Main function is to remove water from the

undigested food

• End of notes for the year