Digestion
•Phases Include
1.Ingestion
2.Movement
3.Mechanical and Chemical Digestion
4.Absorption
5.Elimination
Digestion
•Types
–Mechanical (physical)
•Chew
•Tear
•Grind
•Mash
•Mix
–Chemical
•Enzymatic reactions to improve digestion of
–Carbohydrates
–Proteins
–Lipids
Digestive System Organization
•Gastrointestinal (Gl) tractGastrointestinal (Gl) tract
–Tube within a tubeTube within a tube
–Direct Direct link/path link/path between organsbetween organs
–StructuresStructures
•MouthMouth
•PharynxPharynx
•EsophagusEsophagus
•StomachStomach
•Small intestineSmall intestine
•Large IntestineLarge Intestine
•RectumRectum
4
Mouth
•Teeth mechanically
break down food into
small pieces. Tongue
mixes food with saliva
(contains amylase,
which helps break down
starch).
•Epiglottis is a flap-like
structure at the back of
the throat that closes
over the trachea
preventing food from
entering it. It is located
in the Pharynx.
Esophagus
•Approximately 20 cm long.
•Functions include:
1.Secrete mucus
2.Moves food from the throat to
the stomach using muscle
movement called peristalsis
•If acid from the stomach gets in
here that’s heartburn.
Mouth, Pharynx and Esophagus Video Video
Stomach
7
•J-shaped muscular bag that stores the food you
eat, breaks it down into tiny pieces.
•Mixes food with Digestive Juices that contain
enzymes to break down Proteins and LipidsProteins and Lipids.
•Acid (HCl) in the stomach Kills Bacteria.
•Food found in the stomach is called Chyme.
Small Intestine
•Small intestines are roughly 7 meters long
•Lining of intestine walls has finger-like
projections called villi, to increase surface
area.
•The villi are covered in microvilli which
further increases surface area for
absorption.
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Crash Course Review
Small Intestine
•Nutrients from the food pass into the
bloodstream through the small
intestine walls.
•Absorbs:
–80% ingested water
–Vitamins
–Minerals
–Carbohydrates
–Proteins
–Lipids
•Secretes digestive enzymes
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Large Intestine
•About 1.5 meters long
•Accepts what small intestines don’t
absorb
•Rectum (short term storage which
holds feces before it is expelled).
Large Intestine
•Functions
–Bacterial digestion
•Ferment carbohydrates
– Absorbs more water
– Concentrate wastes
Accessory Organs The Glands
•Not part of the path
of food, but play a
critical role.
•Include: Liver, gall
bladder, and
pancreas
Liver
•Directly affects digestion by producing
bile
–Bile helps digest fat
•filters out toxins and waste including
drugs and alcohol and poisons.
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Gall Bladder
•Stores bile from the
liver, releases it into the
small intestine.
•Fatty diets can cause
gallstones
Pancreas
•Produces digestive
enzymes to digest fats,
carbohydrates and
proteins
•Regulates blood sugar
by producing insulin
Web Page Web Page Reinforcement Video
On a sheet of paper, write the name of
each colored organ:
•Green:
•Red:
•Pink:
•Brown:
•Purple:
•Green:
•Yellow:
How’d you do?
•Green: Esophagus
•Red: Stomach
•Pink: Small Intestine
•Brown: Large Intestine
•Purple: Liver
•Green: Gall Bladder
•Yellow: Pancreas
Great Job!
10/09/25
1.The process by which food is broken down into simpler substances is
called __________.
2.The first part of the digestive system is the __________.
3.The teeth help to __________ the food into smaller pieces.
4.The tongue helps in __________ and tasting the food.
5.The tube that connects the mouth to the stomach is called the __________.
6.The __________ is a muscular organ where food is mixed with digestive
juices.
7.The partly digested food in the stomach is called __________.
8.The __________ produces bile that helps to digest fats.
9.The greenish fluid stored in the gallbladder is called __________.
10.The __________ produces digestive enzymes and insulin.
1.Most digestion and absorption of food takes place in the __________.
2.The inner walls of the small intestine have tiny finger-like structures called
__________.
3.The __________ absorbs water and minerals from the undigested food.
4.The solid waste is stored in the __________ before it leaves the body.
5.The opening through which waste leaves the body is called the __________.
6.The process of taking food into the mouth is called __________.
7.The breaking down of food by the action of digestive juices is called __________
digestion.
8.The __________ helps push the food from the mouth to the stomach using
wave-like movements.
9.The __________ helps in the chemical digestion of proteins in the stomach.
10.The undigested food is finally removed from the body through the process called
__________.