1.Define the words “organ” and body system and give examples of the differences between them.
Organ- a group of different types of tissues that work together to perform a specific function. (Heart,
stomach, lungs, brain)
Body system- a group of organs that work together to perform a specific function. (Circulatory system,
digestive system, respiratory system, and skeletal system)
2. Describe how food moves through the digestive tract. The food is chewed in the mouth and is
mixed with saliva. The tongue moves the food around and helps form a soggy ball of food called a
Bolus. You swallow the food and peristalsis or (muscular contractions) of the esophagus move food on
to the stomach. These muscular contractions continue to help food continue to move the food along
through your small intestines, large intestines, and rectum.
3. List the steps involved in performing chemical tests for sugar and starch, and be able to conduct
these test.
Sugar- Use a pipette to withdraw the solution being tested. Add 20 drops of the solution into a test tube.
Next add 10 drops of the indicator “Benedict’s solution”. Place the mixture into a hot water bath for
one minute. Remove and observe for any color change in the solution in the test tube. The dark orangered indicates more sugar than green or yellow. If the color is blue (the color of Benedicts) then the
solution doesn’t have sugar.
Starch- Add 3 drops of the indicator Lugol to a solution mixture or directly on the substance, if a solid.
Black or dark purple indicates starch is present.
4.State the function of digestive enzymes. A special protein that speeds up the process in which the
body breaks down nutrients into forms that the body can use.
5.Name the digestives enzymes in the mouth and stomach.
Amylase (mouth) - breaks down starch into simple sugar
Pepsin (stomach) - when combined with Hydrochloric Acid begins the break-down of proteins into amino
acids.
Gastric Juice- is made up of pepsin and amylase.
6.List at least four food sources of proteins, of carbohydrates, and of fats
Proteins- meat, eggs, milk, beans
Carbohydrates- bread cereal, pasta, rice (grains)
Fats- cooking oils, butter, mayonnaise, fatty cuts of meats
7.Explain why the body needs proteins, carbohydrates, and fats
Proteins- build and repair body tissue
Carbohydrates- quick energy
Fats- energy and insulation
8.Describe the function of the sphincter muscles.
A ring of muscle, that aids in the one-way passage of food through the digestive system.
9.Explain the function of mucus. A thick sticky substance that lines and protects the inner walls of the
digestive organs. It facilitates the passage of food through the digestive tract and helps protect the walls
of the digestive tract from being digested.
10.Define and give examples of diffusion and indicate why it is also called passive transport.
Diffusion- the process by which molecules move from an area of high concentration to an area of low
concentration. It is also called passive transport because the absorptive process requires no energy from
the cell.
11.Explain the difference between active and passive transport and indicate the importance of both
processes in absorption. Passive transport- a process in which substances pass through the cell
membrane from where they are more concentrated to a place where they are less concentrated, without
using energy from the cell.
Active Transport- the process by which materials using energy supplied by the cell are moved across a
membrane.
These processes keep all needed nutrients and wastes moving smoothly to and from every cell in your
body.
12.Indicate why the small intestine needs an extensive internal surface area.
The more surface area allows more time for food to be broken down. If we didn’t have such an
extensive internal surface area, the food would exit the body before it had time to break down the
food to a form that the body could absorb.
13.Explain the functions of the large intestine and indicate what conditions may arise when
undigested wastes passes too quickly or too slowly through the large intestine. The role of the large
intestines is to absorb excess water and minerals back into the bloodstream.
If the feces move through too quickly, there is not enough time for water to be absorbed. (DIARRHEA)
You often get abdominal cramps…which are strong contractions of the large intestines. Diarrhea is
dangerous, because you can become dehydrated…especially an infant.
If the feces move through too slowly too much water is absorbed and Feces becomes larger, harder, and
drier. This results in CONSTIPATION. To avoid being constipated you should eat food that is high in
fiber. If you are constipated some times you might need to take a laxative. Laxatives cause peristaltic
contractions to increase and move waste through the colon more quickly.
14.List in order the organs of the digestive tract, beginning with the mouth.
Mouth, esophagus, stomach, small intestines, large intestine, and rectum.
15.What is Chyme? A name given to food in the stomach after it becomes a thick creamy liquid.
16.Where is fat digestion begin? Small intestines
17.Where is protein digestion begin? Stomach
18.What part of the large intestines stores wastes until it is ready to be eliminated? Rectum
19.Where does most chemical digestion occur? Small Intestines
20.What part of the large intestines has no known function in humans? Appendix
** Know what is occurring in the diagrams on pages 29,46,47, 52 (fig. 7.2)
** Know what should be occurring in the data table on the front of lab 4.1, lab 5 (the last two
pages), and from lab 8 you should be able to calculate surface area of a solid rectangular object.
Make sure you use the proper unit. (square centimeters) Length X Width of every side and add
all six sides together.
Lab 6 – test tube diagram will be on your test. Know what happens to sugar(it diffused through
the membrane) and starch(it didn’t diffuse through the membrane.
**Know the two types of digestion:
Mechanical:
Teeth, tongue chew food(mouth); stomach muscles churn and mix food. Esophagus, stomach, intestines
use the peristalsic(muscular) contractions to move food your digestive tract.
Chemical:
Mouth- Amylase
Stomach- Gastric Juices(pepsin, and
Hydrochloric Acid)
Intestines: receive Bile, more Amylase, and other enzymes not mentioned in your book.