Transcript Digestive System Facts

Human Digestive System
From start to finish
 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 answers
1. 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)
 Liver
 Gastric glands (stomach)
 Pancreas
 Intestinal glands
 Gall 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
transformationcomplex
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
-mouthpharynxesophagus
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
o Chewing = cut, crush and grind food
- in mouth
o Churning = 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
stomach
protein
Intestinal Intestinal Small
Glands juice
intestine
Proteins,
carbohydrates, fats
Pancreas Pancreatic Small
intestines
juice
Proteins,
carbohydrates, fats
Liver
Bile
Small
fats
intestines
Digest.wmv
Lab 50- observing a mechanical and
chemical change
 Long lab but cool
 Water, minerals, vitamins = directly absorbed
without transformations
Nutrients requiring chemical transformation
nutrients
molecules
Proteins
Amino acid
Carbohydrates
glucose
Fats
Fatty
Glycerol acid
Bile activity (#52)
Discussion: textbook pg. 194-5 Q 4& 6
(skip 5)
Homework workbook pg. 97 & 98
Digestive System Facts
 It 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 Facts
 The 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