Download A) How Chewing Helps Digestion?

Levels of Organization and Organ Systems
The human body is structured into ______. Recall that cells are the smallest units of
life. Cells that are similar in _____ and _______ work together as _____. The human
body has four primary kinds of tissue:
Epithelial tissue –
Connective tissue –
Muscle tissue –
Nervous tissue –
Different types of tissues work together to form _________, which carry out
particular functions. Examples include, ______, ______, ________ and _______.
Organs cannot do all of the necessary work to sustain the body on their own. They must
work together with other organs with related functions (____________) or structures
(_________). This is referred to as an ________________.
The following is a list of the body’s major organ systems and their functions:
Organ System
Major Organs
Esophagus, stomach, intestines,
liver, pancreas
Heart, blood vessels
Lungs, trachea, blood vessels
Major Function
Physical and chemical breakdown of food
Transportation of nutrients, gases and
waste; defence against infection
Gas exchange
Testes, vas deferns, ovaries,
uterus, fallopian tubes
Kidney, bladder, ureter, urethra
Sexual reproduction
Bones, muscles
Movement of body and body parts
Pancreas, pituitary gland,
adrenal glands
Brain, spinal cord, eyes, ears,
nose, tongue, nerves
Coordination and chemical regulation of body
activities
Response to environment; control of body
activities
Removal of waste
What is Nutrition?
Nutritional science is the study of _______ and ______________ found in foods that
affect human _______ and ___________. A thorough understanding about nutrition
enables people to make ___________________. A nutrient is an _____ _______
that is broken down by the body. Good nutrition is important because it:
a) Provides the ________ we need to carry out all of our __________________.
b) Provides us with the essential _____________ that we need as building blocks.
There are three main categories of nutrients:
1.
MACRONUTRIENTS (Macromolecules)
Macromolecules are required by the body in _______ amounts. These molecules form
the _________ and carry out the _______ of all cells. They are ________ molecules
that may contain anywhere from _____ to ___________ of carbon atoms.
Because of their _____ and the intricate ______ that macromolecules can assume,
these large molecules are capable of performing a wide variety of complex ______ with
great __________ and __________.
Macromolecules are ___________ of smaller units (__________) linked together.
There are four classes of macromolecules in cells:
i. CARBOHYDRATES
ii. LIPIDS
iii. PROTEINS
iv. NUCLEIC ACIDS
(polymers of ___________)
(polymers of _________________)
(polymers of ______________)
(polymers of ________________)
Monomers are linked together by __________ bonds. _________ are responsible for
the __________ and __________ of macromolecules.
2.
MICRONUTRIENTS
Micronutrients are needed by the body _______ amounts. There are two main classes
of micronutrients:
i. Mineral -
an ________ substance (such as copper, iron, calcium or phosphorous)
that is needed in all body structures in ________ amounts for various
functions, such as the transmission of ___________ and ______
contractions; ___________________________, therefore must be
supplied by _________ or __________________
ii. Vitamin –
an ______ molecule that acts as a ______ for essential __________
in the body, such as converting fats and carbohydrates into energy; can
be ______________ or ____________;
____________________________, therefore must be supplied by
______ or ___________
3.
Special Nutrient
Water is the considered a special nutrient and is required by all living things. Water is
the most abundant molecule in any cell (constitutes _________ of the human body). It
functions to act as a carrier for ______________ inside (___________) and outside
(___________) of the cell, and as a medium for ________________ (___________).
It also functions as a _____________ between organs, tissues and individual cells.
The following properties of water make life possible, as we know it:
a)
b)
c)
Remains ________ over wide range of temp (1C - 99C)
_________ most substances involved in living processes such as _______,
__________, _______, __________ and ___
Changes temperature gradually (_____________________) when heated
or cooled so it protects cells from rapid temperature changes and therefore
a stable environment
A balanced diet should provide all essential vitamins and minerals. Supplements maybe
required for those who are ill, planning to have children, recovering from injury,
suffering from digestive problems or choose not to eat an optimal diet.
Canada’s Food guide recommends the following daily servings for a balanced diet:
Food Group
Daily Servings
Grain
Vegetables
and Fruit
Milk Products
or Substitutes
Meat and
Alternatives
Macromolecules
Carbohydrates
A green plants ability to get energy from the Sun and turn ___ from the ____ into
_____ (carbohydrates) is called ___________ and is represented by the chemical
equation below:
Therefore, all carbohydrates come from green plants. Carbohydrates are nutrients
based on molecules of sugar; because of this they are called “___________” which
means “_____”. All carbohydrates have the general formula C-H2O, in other words they
are “carbon-hydrates”. The function of carbohydrates are to act as the
_______________________ in cells as they pass through the process of ______
_______________, which is represented by the chemical equation below:
In photosynthesis _________________ is used to produce energy rich ______
molecules (glucose).
In respiration the ______ molecule (glucose) is broken down and releases ______ (in
the form of ATP) for the cell to use.
Two important organelles are specialized for energy conversion.
1.
2.
There are two main varieties of carbohydrates that we consume,
simple sugars such as monosaccharides (_______ and _______)
or disaccharides (______ and ______), and ___________________ (_______ –
________ of sugar in __________).
_______ is a carbohydrate that acts as a storehouse for _________ in _______. It
is produced in the ____. Excess amounts of glycogen get converted into _____.
Fibre is a carbohydrate (______) that cannot be _______ by humans. It helps to hold
_______ and provide ______ in the large intestine, thus it helps to eliminate our
waste.
Current North American guidelines recommend that carbohydrates, especially
________ carbohydrates provide ____ to ____ of your daily energy requirements,
which should be approximately ________. _______, ______ and _________ are
excellent dietary sources of carbohydrates. When your diet is rich in carbohydrates,
your body extracts energy from them, saving ________ for muscle building and body
repair.
Lipids
Fats serve as a ________________________ along with providing insulation and
acting as hormones. Current guidelines recommend that dietary fats should supply no
more than ____ of your daily energy requirements. There are two main types of fat we
consume, _______________ and ________________.
Triglycerides are composed of a _______ molecule attached to ______________
chains. The fatty acid chain determines the type of triglyceride.
A)
Saturated Fatty Acids
There are only single bonds between each carbon atom. This organization allows
for a ____ arrangement of the fatty acid tails, allowing them to ____ close
together, which explains why saturated fatty acids are _____ at room
temperature. These are found in foods such as _____, _____, _______ and
_____. Saturated fats are closely associated with __________. They can
increase “bad cholesterol” (___) and decrease “good cholesterol” (___).
B)
Unsaturated Fatty Acids
There is one (______________) or more (_____________) ______ bonds in the
carbon chain. This means that not every carbon is bonded to its maximum number of
hydrogen atoms.
Double bonds produce _____ in the fatty acid chain, consequently, the more double
bonds the chain possess, the greater the difficulty for these chains to pack together.
This explains why unsaturated fats form ________ at room temperature (___). These
are found in foods such as ___ or soft _______.
Most naturally occurring unsaturated fatty acids are found in what is called the ___configuration. These types of fats appear to ______ total cholesterol levels.
Unsaturated fats can have their double bonds chemically ________ with hydrogen
atoms (a process termed ______________). During this process ______ fats are
produced. The resulting molecule creates ________ chains, which are capable of being
_______ at room temperature, such as _________. Trans-fats elevate ___
cholesterol levels and lowers ___ cholesterol levels. They are thought to be
___________ to human health.
Omega-__ and omega-__ fatty acids are essential fats found in ___, ______, ___ and
______________ that are required to build ______, the protective covering around
__________ of our ________ cells.
There are two types of cholesterol; about ____ of cholesterol is made by our ___, while
the other ____ comes from _______:
1. Dietary Cholesterol
 Found in foods containing animal
fat - _____________________
_________________________
 Doesn’t normally cause blood
cholesterol to ___________ in
most people
2. Blood Cholesterol
 Most of this cholesterol is produced by the ________
 Two types - HDL and LDL
HDL (good) - High-Density Lipoprotein
 Contains less lipids and more proteins
 Helps ________________________ from body
 To boost HDL - _______, be _________ and maintain ________________
LDL (bad) - Low-Density Lipoprotein
 Contains more lipids and less proteins
 Clogs arteries because these are deposited on artery walls (______), blocks
circulation, increases risk of ______________ or ________
 To lower LDL - cut down on ____________ and _____ fats, eat more foods
containing soluble ________
Proteins
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Account for _____ of the dry weight of cells
Wide variety of _______ in organisms – _______________________etc…
Huge variety of _________ - each protein has a unique _______________
_______
Always assembled from a common cellular pool of _________________
__ of the 20 amino acids are considered ______ amino acids as they cannot be
produced by the body, but must be obtained through _____
Proteins should make-up __________ of daily energy requirements
Animals sources such as ___________________ and ______ are sources of
___________ proteins (provide all 8 of the essential amino acids)
_______________ and __________ are ____________ proteins, because
they do not provide all the essential amino acids
Vegetarians attempt to avoid all meat products, although may consume dairy and
egg products. Vegans will restrict their diet to foods derived from plants
Vegetarians and vegans must carefully balance their food intake in order to
obtain all eight essential amino acids
An amino acid is composed of a ______ atom (called the _____ carbon) ________
bonded to four different groups:
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Types of Digestion
All organisms must have some way of obtaining essential ________ needed to make
their own structures and to perform life functions. Organisms that depend on organic
molecules manufactured by other living things are called _____________.
Digestion can occur _________ or _________. External digestion is thought to be the
first type of system to evolve and organisms such as _______ and _______ still rely on
it today. In this process, enzymes are ________ into the environment surrounding the
organism, where they break down organic material and then some of the products
____________ (move from an area of _____ concentration to ____ concentration)
back to the organism.
Internal digestion evolved later, where animals make use of a ______ system to digests
organic material ______ of their body. This method is more efficient as it allows
organisms to _______ and _______ their food and _______ and _______ the
environments more effectively for the digestive process.
Digestion can also be considered as ___________ or ___________. Intracellular
digestion is the type of digestion in which food particles are taken ____________ and
subjected to the action of enzymes there. Extracellular digestion is the digestion of
food occurring ______________________________ (as in the tube arrangement
common in animals).
Types of Digestive Systems
There are three main types of digestive systems:
1.
2.
3.
All of these systems follow the same four steps:
Ingestion –
Physical and Chemical –
Breakdown
Absorption –
Egestion –
1. Vacuole System
Food is digested inside a vacuole formed within the cell.
Examples: _______________ and ___________
2. Closed Tube System
This type of digestive system consists of a “__________”
structure with only ______________. Both ingestion and
excretion occur through the same opening.
In the digestive cavity, food is partially broken down by
enzyme action and absorbed into cells lining the inside of
the "bag". These cells complete the digestion process.
Example: _____________ and a _____________
3. Open Tube System
This type of digestive system consists of a tube with ____
openings. One opening is used to ingest food particles and
the other is used to excrete waste. Examples: ________
and ___________. Open tube systems usually require:
1.
2.
Ingestion
Digestion is a complex process, which results in food being broken down
into its component molecules. It involves:
1) Mechanical (Physical) Digestion
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2) Chemical Digestion
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In humans, the digestion process takes about ______ hours and
requires passage through an extremely long tube system
(_________________), separated into distinct regions that
perform specific functions.
Section
Length
The Mouth and Pharynx
Both physical breakdown and chemical digestion occur in the mouth. The
______ and _______ are important for ______ digestion and the
______________ for ___________ digestion.
Inside of your mouth, covering the surface of your tongue are tiny
projections called _________, and every one holds hundreds of
_____________.
Taste is closely linked to _______ (smell); much of what we call the taste
of food is actually the _________. Taste is a combination of sensations –
______, ______, ______ and ______.
One theory is that taste buds for the different sensations are clustered in
specific regions on the surface of the tongue. Can you figure out where
these clusters are located?
Sweet
Sour
Salty
Human teeth
Type of Tooth
Incisor
Canine
Premolars
Molars
Wisdom
Number
Function
Each tooth has two divisions, the ____ and
an ___________. Enamel, which is formed
of _______compounds, is the _________
substance in the body.
Bitter
A) How Chewing Helps Digestion?
Sugar
Appearance Before
Loose
Appearance After
Cube
B)
How did the surface area of the types of sugar compare?
C)
How does surface area affect the rate of dissolving?
Chemical digestion begins as food is chewed, and it begins to mix with
_______ produced by the three salivary glands – ______, _______ and
____________.
Some functions of saliva include:
 It wets and __________ so food can be swallowed easier and begins
the _________ process (required for _______ and
_____________)
 It causes the food particles to stick together
to form a food mass, or _______
 It contains a digestive enzyme called ______
(or ________________), which breaks down
starch into simple carbohydrates
The tongue pushes the food ____ to the back of
the throat, and against the _______________,
which initiates the automatic __________ reflex.
The _________ prevents ____ and _______ from
entering the ______ during swallowing, while the
______ stops food from entering the ________ cavity.
The Esophagus
No digestion, neither ______ nor _______ occurs in the esophagus. It
secretes ________, a lubricant which aids the bolus of food in its journey
to the stomach.
The movement of food down the digestive tube is aided by
_____________.
Peristalsis consists of alternate waves of
_________ and __________ in the
muscular walls of the alimentary canal.
Where the esophagus opens into the
stomach, there is a ring of muscle called a
__________.
The ________________ acts as a valve
and controls the passage of food from the
__________ into the ___________.
__________ or acid indigestion occurs
when ____________ backs up into the
esophagus, _______ its lining. Pain is felt
in the region of the _____ where the
esophagus is located, but the condition has
nothing to do with the heart.
The movement of food out of the stomach,
up the esophagus and out the mouth is called _________________.
The Stomach and Intestines
Through the digestive process, macromolecules are broken down into molecules small enough to
be ____________ from the intestine and transported to ______ cells:
Carbohydrates
Proteins
Lipids (triglycerides)
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___________ is the main process in which food is chemically broken down. During hydrolysis, a
water molecule is added at the point where a _____ occurs between __________. Hydrolysis
occurs at a very slow rate, but is immediately sped-up by ______________ (biological
catalysts made of _____________).
Enzymes are formed by _________ cells, which can exist ______, in ________ or in _______.
A gland is a structure made up of a complex system of tubules connected to other areas by
_______. Enzymes are very _________ and will only catalyze specific _________. Many
enzymes require the presence of ________ or _______ in order to function properly.
The Stomach
The stomach is the site for temporarily storage
of ____ and initial _____ digestion. Both
________ breakdown and _________ digestion
occurs here. Physically the stomach has a
________ appearance and can hold up to _____
of food.
Food is broken down mechanically into smaller
particles by the _________ of the ________
stomach walls (______ muscles). This is referred
to as __________.
The food mass is churned and mixed with ______
juice secreted by two types of glands:
1. Pyloric glands
Secrete _________, which covers the stomach lining and __________ it.
2. Gastric glands
Secrete very _____ gastric juice, which has a pH of ___ to ___. Gastric juice
contains hydrochloric acid (____) and the digestive enzyme __________. When
pepsinogen is converted to its active form of ______, the breakdown of _______
into their individual _______________ begins.
There are three mechanisms involved in stimulating the flow of gastric juice:
1. The _______________, or _____ of food stimulates the ____ to send messages via nerve
impulses to the __________________.
2. Food ___________ the ___________ of the stomach.
3. Secretion of the hormone _______ caused by _________ of the ____________. Gastrin
stimulates production of large amounts of _______________.
In a typical day __ litres of fluid pass through the lumen of an adult’s gastrointestinal tract.
Only about __ litres of that volume enters through the ____. The remaining __ litres come
from body _________ secreted along with _________ and __________.
A common disorder associated with the stomach occurs following the destruction of the
___________ in the stomach. This leads to a __________. Until recently, ____ and _____
were always thought to be the leading cause of ulcer formation. Scientists have now discovered
a remarkable organism, ________________, which thrive in the stomach’s ____________
environment and are believed to cause most cases of ulcers.
The Small Intestine
Most chemical digestion and almost all absorption of nutrients occur here. After food leaves
the stomach, regulated by the ________________, it enters the first part of the small
intestine called the ________. At this stage, the partially digested food is called _______.
The presence of chyme in the small intestine, stimulates secretion of the hormone _______
and ____________________. When these hormones reach the pancreas and liver they
stimulate the production of _______________ and ____.
The small intestine itself produces a number of enzymes that continue the chemical
digestion process, such as:
 Secretes ______________ which completes the breakdown of ______________
 Secretes ______________ which complete the breakdown of _____________
Peristaltic contraction continue throughout the intestines which has 3 main effects:
1.
2.
3.
They ___________ chyme through the intestine moving the bolus along
They _________ the chyme with digestive enzymes and break down food particles
mechanically
Bring the intestinal contents into contact with the intestinal wall speeding
______________
The Pancreas
 Produces ___________________ which ______________ stomach acid
 Secretes the digestive enzymes __________________________________ and
_________________
 Produces _________ and __________ in response to __________________
 Insulin makes ________________ more _________ to ______ and __________
_______________ to _________ blood sugar levels
 Glucagon ________ blood sugar levels by stimulating the breakdown of ________ in the
___________
 Insufficient insulin production can lead to ______________
The Liver
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Produces ______ – an _________ agent needed for the physical digestion of ___
Bile is stored in the ________________
Storage of _____________________ and ____________ (______________)
_______________ many harmful substances (____________)
Excessive damage to liver tissue can lead to the development of __________; a condition
called _________________
Absorption
During absorption, digested nutrients pass through _____________ and enter _________ or
_____ in structures called ______.
The capillaries act to absorb ___________________________ etc… into the ________
system. Lacteals are part of the __________________ and absorb ____________ and
_______ into tiny vessels.
The small intestine has a number
of structural features that
increase its surface area for
maximum absorption of
nutrients:
1.
2.
3.
4.
The small intestine is very ________
Its lining has many _______
The lining is covered with millions of ________________ called ______, which increase
the _______________ by as much as ______ times
The epithelial cells of the villi that face into the intestinal opening have tiny projections
called _____________ that further increase the surface area
_______ disease is an ___________ disorder of the small intestine that occurs because of a
reaction to _____ which is found in ____ products. Exposure to gluten causes the villi of the
small intestine to ________. This interferes with the ____________ of nutrients and water
causing ______________ and ___________________.
_________ disease is a chronic ____________ disease of the intestines, primarily caused by
________ in the small and large intestines, but can affect the digestive system anywhere
between the ____________ and the _________.
The Large Intestine
____________ and _______________ materials pass from the small intestine into the large
intestine. No digestion occurs in this portion of the digestive system.
Functions of the large intestine include:
1. Reabsorption of _________ from the food mass
2. Absorption of vitamins __ and __ produced by live _____ in the large intestine
3. Elimination of undigested and indigestible material from the digestive tract (____)
Examples: ________ from plant cell walls, large quantities of ________________ and
__________________ from the digestive tract
Fecal matter is stored in the last part of the large intestine, the ___________, and
periodically eliminated, or ______________, through the _______.