3.1 Digestive System

3.  Digestive
 Respiratory
 Circulatory
 Excretory
 Nervous

4.  In order for your body to get energy the food
we eat must pass through the digestive
system
 It is in charge of breaking down food into
small enough parts to be used by cells

7.  Take the crackers you have in front of you
and chew them up well..BUT DO NOT
SWALLOW THEM!!!!
 Hold them in your mouth for 5
minutes….starting….
 Answer the questions as you go.

8.  How did the crackers taste as you first
chewed them?

9.  Describe how the taste changed as you
neared the 5-minute mark?

10.  What do you think caused the any changes
you experienced?

11.  Mechanical – the physical breakdown of food
into very small pieces
 Chemical – breakdown of large particles into
smaller particles using ENZYMES.

12.  The digestive system is merely a pathway
where food follows long tubes with a few
compartments
 It starts at the mouth and finishes in the
rectum

13.  This is the first stage of digestion that occurs
in this pathway
 Mechanical digestion occurs with the chewing
of the food using teeth
 Saliva in the mouth moistens food and adds
an enzyme called salivary amylase.

15.  When your food is fully chewed your tongue
pushes it to the back of your throat
 Swallowing pushes the food down your throat
into your esophagus
 The food is pushed towards your stomach by
wave-like movement called Peristalsis
 They are caused by the contracting and relaxing of
muscle tissue around the esophagus

17.  Deals with the arriving food with a few
processes;
◦ The muscular stomach wall churns food back and
forth
◦ This mixes the food with the secretions from the
wall of the stomach, called GASTRIC JUICE

18.  Gastric Juice is made up of
◦ Mucus
◦ Hydrochloric Acid
◦ Water
◦ Digestive Enzymes

19.  The Hydrochloric Acid and enzymes help
chemically breakdown the larger particles
 The mucus helps prevent the gastric juices
from digesting the stomach itself
 The stomach slowly releases the food, which
is now a liquid, into the small intestines

21.  The average length of an adult human male is
about 22 feet 6 inches or 6.9 meters
 In women it is 23 feet 4 inches or 7.1 meters

22.  Chemical digestion continues in the small
intestines
 The PANCREAS sends in more digestive
enzymes to further help the breakdown
 The small intestines itself releases more
enzymes to assist the pancreas

23.  Once the food has been broken up the small
intestines absorbs as much as it can
 To catch as much as possible the intestines
use VILLI – finger like projections that absorb
nutrients
 The absorbed nutrients go directly into the
blood stream

25.  The liver produces BILE
 Bile is stored in the GALL BLADDER
 The gall bladder sends bile into the small
intestines to assist in more chemical
digestion

27.  When food reaches large intestines
mechanical and chemical digestion is
complete
 They absorb water, vitamins and minerals
 Whatever is left forms into feces and is stored
in the rectum