DIGESTIVE SYSTEM

!2

! 4 processes ! Ingestion – taking in of food ! Digestion – breakdown of food into small

components ! Absorption – cells soak up digested material ! Elimination- removal of waste from the body

Digestive System ! Approximately 10 m in length (adult) ! Function = break down food into small

molecules so they can get INTO cells & be used

!5BEFORE

True/ False Stomach muscles contract when we are hungry.

True/ False Sulfuric acid is the acid found in our stomach.

True/ False Mucus protects our stomach from the acid.

True/ False Our stomach lining is replaced every week.

True/ False Our digestive system is a tube.

True/ False Astronauts have trouble moving food along their digestive tract because of the zero gravity.

True/ False About 250 mL of saliva is made per day.

True/ False On average, people need to ingest about 1000 calories per day.

MOUTHStructure Function

Teeth, tongue, salivary gland

Teeth and tongue mechanically break down food Salivary glands add chemicals to break down food

ESOPHOGUSStructure Function

Muscular tube connecting mouth to stomach

moves food along Peristalsis – independent of gravity

STOMACHStructure Function

Muscular sack that can stretch 3 muscle layers

breaks down food with gastric juices

SMALL INTESTINEStructure Function

7m long, tube Folded to increase surface area

Digestion of food is completed

Nutrients are absorbed

LARGE INTESTINEStructure Function

1.5m long, wide in diameter absorbs water to form solid waste called feces

RECTUMStructure Function12 cm long Begins at end of sigmoid colon

temporary storage for feces When urge to defecate, rectum

ANUSStructure Function

2 muscular sphincters Control the exit of feces during defecation

ACCESSORY ORGANSLiver Gallbladder Pancreas

! produce/ release chemicals that aid in the breakdown of food

! eg. Bile, enzymes

! The liver and pancreas have jobs in other systems also.

Homework