DigestiveAnd ExcretorySystems

Digestive System

Functions of the Digestive SystemDigestionWaste Removal (solid)Conversion of food energy to energy usable by the bodyAbsorption of nutrients.

Organs of the Digestive SystemMouthSalivary glandsEsophagusStomachSmall IntestineLarge IntestineLiverPancreas

Digestive Process

In the mouthFood is chewed and swallowedEnzymes are added to food in this process.Once swallowed, it moves down the esophagus to the stomach

EnzymesProteins that catalyze, or increase the rates of chemical reactions.

PeristalsisProcess where food is moved through the digestive system by waves of rhythmic muscular contractions.

In the stomachStrong acid and powerful enzymes mix with the food and break down the food into chyme.

It is then moved to the small intestine.

In the Small IntestineSecretions from the small intestine, liver, and pancreas finish breaking down the proteins, carbohydrates, and fatsMost of the absorption of nutrients takes place in the small intestine

In the Large IntestineVitamins, Minerals, and Water are absorbed.

Role of the Liver in digestionSecretes chemicals that help digest fats in the small intestine.

Stores energy reserves.

Role of the Pancreas in digestionSecretes enzymes that break down carbohydrates and proteins in the small intestine.

Excretory System

Functions of the Excretory SystemRemoves waste made by cellsMaintains salt contentwater contentblood pressureacid-base balance

Organs of the Excretory SystemKidneysLungsSkin

KidneysFilter blood about 10 times a day. (about 1 liter per hour)

NephronsBlood filtering units in the kidney.Each kidney has millions of them.They remove salts, water, and cell waste from the blood.99% of the water removed by the nephrons is reclaimed by the capillaries.Liquid waste is called urine.

Urinary TractUreter tube that carries urine from the kidney to the urinary bladder.

Urinary Bladder stores urine.

Urethra tube that runs from the urinary bladder to the outside of the body.

LungsRemove carbon dioxide (CO2) from the blood and expels it from the body

SkinExcretes water, salts, small amounts of hydrogen wastes, and other substances such as toxins in sweat