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Grade 11 Biology
Unit 2: Digestion and Nutrition
Grade 11 Biology
Unit 2: Digestion and Nutrition
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Grade 11 Biology
Unit 2: Digestion and Nutrition
Introduction to Digestion
The main function of the digestive system is to disassemble food you eat
into molecules so it can be used by your body for energy. The pathway that
food takes as it moves through the body during digestion is known as the
digestive tract or the
canal.
Five Stages of the Digestive Process
1. Motility –
____
2. Secretion –
3. Digestion –
4. Absorption –
5. Elimination –
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Grade 11 Biology
Unit 2: Digestion and Nutrition
Structures Involved in Human Digestion
Mouth
Food enters the ______________________ through the mouth.
Inside the mouth there are two types of digestion:
A) ______________ (physical) Digestion
 __________ break up food into smaller pieces
 __________ guides food to the back of the mouth
B) _____________ Digestion
 As food is chewed, ________________ in mouth secrete
___________
 __________ cups of saliva are produced by salivary glands
each day
 Saliva is composed of ________, mucous and __________
 Salivary Amylase (___________) breaks down ___________
into smaller molecules
 Saliva provides _____________ for chewing and
____________
 Saliva helps maintain ______in the mouth and helps regulate
_____________.
There are three glands:
1. ____________ gland
 located just in front of and slightly below
the ear
 ___________ of the glands
 secretes ___________, an enzyme
(_______________), and a
_____________ fluid into the mouth
2. ________________ gland
 located below the _________ gland near
the angle of the lower ______
 produces ______________ fluid and some
___________ into the mouth
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Grade 11 Biology
Unit 2: Digestion and Nutrition
3._________________ gland
 located under the ______________ and
secretes mostly thick, stringy
____________, salts, and _____________
Pharynx


Most commonly known as the _________________
Serves two purposes:
o moves the _______ into your ________ through ________
o moves ________ into your_________ through __________
Uvula
 a small mass of tissue that hangs down in the back of the mouth, and
moves up to close off the openings to the
when food is swallowed into the esophagus.
Soft Palate
 the roof of the ____________in the back of the mouth
 this soft tissue functions in closing off the openings to the
as food is swallowed.
Epiglottis
 Small flap of ______________ located behind the __________
 Prevents food from entering the ____________tract by
___________ over
the air passage each time you ____________
 When you talk or laugh as you swallow, the ___________ may open,
causing food to enter the upper portion of respiratory tract. Your
response, a __________, is to ________ and ____________,
forcing the food out of the respiratory tract.
Esophagus
 Carries food from _________ to ___________
 Food is passed through the esophagus through:
A. Secretions of _____________
 __________ of inner lining secrete mucus
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Grade 11 Biology
Unit 2: Digestion and Nutrition
B. __________________
 _______________ layers in the esophagus alternatively
__________ and ___________ to push food ahead
(___________________ movement)
Peristalsis Along Esophagus
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Grade 11 Biology
Unit 2: Digestion and Nutrition
Cardiac Sphincter



Separates the ___________ from the ____________
Opens and closes as food passes through
Prevents _____________________ from entering the __________
Stomach








Main function is food ____________
It changes size and shape according to is ___________of the
__________and the __________ of ____________inside
Holds about _____ litres of food
__________, water, and ____________________ combine to form
______________ juice
pH of stomach is about ______
Food remains in stomach for __________ hours and is the
consistency of tomato soup when it is ready to leave
____________ is a mixture of food and gastric juice
Both __________and ______________ digestion take place in the
stomach:
o Physical digestion
 ______________
 Three layers of muscles located within the wall of the
stomach contract to physically break down food into
smaller pieces
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Grade 11 Biology
Unit 2: Digestion and Nutrition
o Chemical digestion
 Inner lining is lined with a layer of __________
 Three types of cells:
 one type secretes ____________ (enzyme)
o breaks down __________ in food
 one type secretes ________________ and water
o kills ____________ and parasites ingested
in food
o provides the optimal ______ for ________
to function
 one type secretes __________
o __________ cells from ____________
juices by forming a ___________ layer
between the __________ and contents of
__________
o __________ are a result of mucus lining
wearing too ________ and cells are
attacked by ___________ juice
Pyloric Sphincter
 Two __________ keep food within ____________
 Muscles____________ to allow partially digested food move into the
_______________________
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Grade 11 Biology
Unit 2: Digestion and Nutrition
Small Intestine
 Small____________ (2-3 cm) but long ____________ (about 6 m)
 Digestion of food is _____________ in small intestine
 Food is moved along by muscle contraction to further
______________breakdown of food
 _______________ digestion of _____________ and proteins
occurs through _____________ produced and secreted by the
______________ and ______________
o Chemical Digestion
 Occurs in ________________ (first 25 cm of small
intestine)
 Most of the enzymes and chemicals that function in the
duodenum enter through ________ that collect
secretions (juices) from pancreas, liver, and gallbladder
Secretions found in Small Intestine (Duodenum)
A) Secretions of ____________

secretes a mixture of enzymes that break down
____________, proteins, and _________.
B) Secretions of ___________

produces__________

bile is stored in ______________ and is then
passed to the duodenum

breaks down ________
o Absorption of Food

As digested food moves through small
______________, it passes over thousands of tiny
fingerlike structures called __________

Mainly occurs in next two sections of small intestine –
___________ and _________

The function of villi is to __________ digested food
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Grade 11 Biology
Unit 2: Digestion and Nutrition


The



Food molecules ___________ or are actively
transported through connective tissue cells into
_____________
Blood travels to _________to remove any excess
__________ or ____________ from blood
Large Intestine
Also called the ___________
1.5 m _____, about 6.5 cm _______
There are _________ portions of the large intestine. These three
sections create an upside-down U-shape and surround the small
intestine.
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Grade 11 Biology
Unit 2: Digestion and Nutrition
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
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Two main functions:
1. Intestinal walls ___________ water and _________
2. Vitamin ____ and Vitamin ___synthesis, which the body
absorbs as needed
Food stays in large intestine for _________ hours
Where the large and small intestine join, there is a small projection
called the _________
o ____________ may _______ and secrete ________ waste in
appendix, resulting in painful inflammation called
_____________
o More common in children than adults because the opening to the
appendix is ________ in children
The only residue of food at the end of the colon is ________,
indigestible waste called ________ which travels to the _________
The Rectum
 __________ are eliminated through the __________
 Feces are 75% __________ and 25% _____________
 30% _________________
 10-20% inorganic matter
 2-3% __________
 30% undigested fiber of the food
 Overall journey of food through digestive tract lasts _____________
hours
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Grade 11 Biology
Unit 2: Digestion and Nutrition
Concept Map of Alimentary Canal
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