From start to finish

Human Digestive System

Write the black Just read the green

WHAT DO YOU KNOW ABOUT THE DIGESTIVE SYSTEM?

Follow along on pg. 93 of your workbook

Functions of the digestive system

Cells can’t use most food as it comes in

Breaks down food molecules (remember matter?) = small enough to enter cells

Eliminate undigested food as feces (poop)

Using pg. 167 of textbook, fill in pg. 93 in workbook

Check your answers1. The digestive tract (in order of pg. 93):

Mouth Pharynx Esophagus Stomach Small intestines Large intestines Rectum

2. Digestive glands (in order of pg. 93)Salivary glands (mouth)LiverGastric glands (stomach)PancreasIntestinal glandsGall bladder

The digestion system

Digestive system model

Homework : workbook pg. 94

Follow along in workbook pg. 95

Digestion is changing (transformation) of food into nutrients so can be used by the body

Mechanical transformation- physically breaking food smaller pieces to prepare for chemical transformation (breakdown).

Chemical transformation- complex molecules simple molecules using digestive secretions (chemicals)

Nutrients= food molecules absorbed by the body (microscopic)

Absorption- passage of nutrients from digestive tract to blood to be taken to cells.

Processing food in the digestive system:

1. Ingestion & propulsion of food

2. Digestion of food

3. Absorption of nutrients

4. Elimination of fecal matter (poop)

Food moves along digestive system by:

1. Deglutination = swallowing -mouthpharynxesophagus

2. Peristalsis= contractions of muscles behind food to push it along -esophagus, stomach, large and small intestines

Before food can be used by the body it needs to undergo changes (transformations) to become nutrients. These are mechanical transformations and chemical transformations.

Follow along on pg. 96 of workbook

oChewing = cut, crush and grind food- in mouth

oChurning = muscle contractions mix food with secretions from digestive glands

- stomach and small intestines muscle

Chemical transformations= Complex molecules simple

molecules by secretions.

Gland secretions location targets

Salivary gland

saliva Mouth Starch (complex carbohydrates)

Gastric Glands

Gastric juice

Small intestine

Proteins, carbohydrates, fats

Intestinal Glands

Intestinal juice

stomach

Proteins, carbohydrates, fats

Pancreas Pancreatic juice

Small intestines

protein

Liver Bile Small intestines

fats

Digest.wmv

Lab 50- observing a mechanical and chemical changeLong lab but cool

Water, minerals, vitamins = directly absorbed without transformations

nutrients molecules

Proteins

glucoseCarbohydrates

Glycerol Fatty acid

Amino acid

Fats

Nutrients requiring chemical transformation

Bile activity (#52)

Discussion: textbook pg. 194-5 Q 4& 6 (skip 5)

Homework workbook pg. 97 & 98

Digestive System FactsIt takes 3 hours for food to move

through the small intestine.

Food drying up in the large intestine can last 18 hours to 2 days.

In your lifetime, your digestive system may handle about 50 tons.

The average person eats about 1.4 kg of food per day.

Digestive System FactsThe intestines are at least 7.5

meters long in an adult.

Chewing food takes from 5-30 seconds.

Digestion from mouth to anus takes about 72 hours.

Food sloshing in the stomach can last 3-4 hours.

DIGESTIVE food--> nutrients

broken down by:

mechanical- chew,

churn, peristalsis

chemical- acids,

enzymes, pepsin

nutrients

absorbed in

small intestine

go into blood to

be taken to cells

Bill Nye Digestion