Download Food and Digestion

Food and Digestion
Complete unit planner by writing today’s activities
and homework in the appropriate spaces.
Answer the following question as today’s bellringer:
Think back over our study of the circulatory system.
It’s major purpose was to transport needed materials
to cells and tissues throughout the body. How might
the circulatory system and the digestive system work
together to accomplish this?
Food and Digestion - Food and Energy
Carbohydrates
In addition to providing energy,
carbohydrates provide the raw materials
to make cell parts.
Food and Digestion - Food and Energy
Fats
Many foods contain saturated, unsaturated, and trans fats.
Unsaturated fats are considered to be more healthful than
saturated fats and trans fats.
Food and Digestion - Food and Energy
Proteins
Proteins are needed for tissue growth and repair. They also
play an important role in chemical reactions within cells.
Food and Digestion - Food and Energy
Vitamins and Minerals
Vitamins act as helper molecules in a variety of chemical
reactions in the body.
Food and Digestion - Food and Energy
Vitamins and Minerals
Nutrients that are not made by
living things are called
minerals.
Minerals are present in soil and
are absorbed by the roots of
plants.
Thus, how do you obtain
minerals in your diet?
Food and Digestion - Food and Energy
Water
Water is the most important nutrient because the body’s vital
processes – including chemical reactions such as the
breakdown of nutrients – take place in water.
Food and Digestion - The Digestive Process Begins
Functions of the Digestive System
The digestive system has three
main functions. First, it breaks
down food into molecules the body
can use. Then, the molecules are
absorbed into the blood and
carried throughout the body.
Finally, wastes are eliminated from
the body.
Food and Digestion - The Digestive Process Begins
Methods of the Digestion
Mechanical digestion – foods are physically broken down into
smaller pieces
Chemical digestion – chemicals produced by
the body break down foods into their smaller
chemical building blocks
Food and Digestion - The Digestive Process Begins
The Mouth
Both mechanical and chemical digestion
begin in the mouth.
Food and Digestion - The Digestive Process Begins
The Mouth
The shape of an enzyme molecule is specific to the shape of
the food molecule it breaks down. Here an enzyme breaks
down a starch into sugars.
Food and Digestion
INDEPENDENT PRACTICE… Draw a Venn
diagram comparing and contrasting
mechanical and chemical digestion.
Food and Digestion
TICKET OUT… Which of the following
activities represent mechanical digestion
and which represent chemical digestion:
1. The teeth cut and grind food
2. The stomach churns food
3. Enzymes in saliva break down carbohydrates in
food
4. Enzymes break down proteins in food
Food and Digestion - The Digestive Process Begins
Protein Digestion
A scientist performed an
experiment to determine the
amount of time needed to digest
protein. He placed small pieces
of hard-boiled egg white (a
protein) in a test tube containing
hydrochloric acid, water, and the
enzyme pepsin. He measured
the rate at which the egg white
was digested over a 24-hour
period. His data are recorded in
the graph.
Food and Digestion - The Digestive Process Begins
Protein Digestion
Reading Graphs:
What do the values on the yaxis represent?
Percentage of egg white
digested
Food and Digestion - The Digestive Process Begins
Protein Digestion
Interpreting Data:
After about how many hours
would you estimate that half
of the protein was digested?
About 14 hours
Food and Digestion - The Digestive Process Begins
Protein Digestion
Interpreting Data:
How much digestion occurred
in 16 hours?
About 70%
Food and Digestion - The Digestive Process Begins
Protein Digestion
Drawing Conclusions:
During which four-hour period
did the most digestion take
place?
From 13 to 16 hours
Food and Digestion
Complete unit planner by writing today’s activities
and homework in the appropriate spaces.
Answer the following question as today’s bellringer:
Describe as best you can the process that turns food
into nutrients that cells can use.
A Great Illustration of Digestion
Food and Digestion - The Digestive Process Begins
The Epiglottis and the Esophagus
The epiglottis is flap of
cartilage located in the throat
behind the tongue and in front
of the larynx.
When a person swallows the
epiglottis folds backward to
cover the entrance of the
larynx so food and liquid do
not enter the windpipe and
lungs.
Food and Digestion - The Digestive Process Begins
The Epiglottis and the Esophagus
The esophagus is a muscular
tube that extends from the neck
to the abdomen and connects
the back of the throat to the
stomach.
The esophagus squeezes the
mass of food with rhythmic
muscle contractions called
peristalsis. Peristalsis forces
the food into the stomach.
Peristalsis Demo
Food and Digestion - The Digestive Process Begins
The Stomach
Most mechanical digestion and some chemical digestion
occur in the stomach.
Food and Digestion - Final Digestion and Absorption
“The Stomach”
Mechanical and chemical digestion takes place in the stomach.
Food is
squeezed by
muscular
contractions.
Tiny glands in
the stomach
produce
enzymes and
acid.
Food is
reduced to a
soupy mixture
called chyme.
Food and Digestion - Final Digestion and Absorption
The Small Intestine
The small intestine is the part of the digestive system where
most chemical digestion takes place.
Food and Digestion - Final Digestion and Absorption
The Small Intestine
Tiny finger-shaped projections called villi line the
inside of the small intestine. Villi absorb nutrient
molecules. The molecules pass from the villi into
blood vessels.
Food and Digestion - Final Digestion and Absorption
“The Small Intestine”
Chemical digestion takes place in the small intestine.
Food mixes
with enzymes
and secretions.
Starches,
proteins, and
fats are
digested
chemically.
Enzymes and
secretions are
produced by
the small
intestine, liver,
and pancreas.
Food and Digestion - Final Digestion and Absorption
Most commonly
known as the
colon…
The Large
Intestine
Food and Digestion
Graphic Organizer
In the mouth, the teeth break food into smaller pieces and saliva
begins to break down starches.
Esophagus pushes food from mouth to stomach.
In the stomach, food is churned and mixed with digestive juices
that break down protein.
In the small intestine, almost all chemical digestion and absorption
occurs.
Large intestine absorbs water and eliminates waste.
Food and Digestion
TICKET OUT… Identify each of the following
statements as true or false…
1. Digestion begins when food reaches the stomach.
2. Breaking, crushing, and mashing food is an
example of chemical digestion.
3. Saliva contains enzymes, which begin the chemical
digestion of food.
4. The esophagus connects the mouth with the small
intestine directly.