Question

the digestive system - the small intestine
the small intestine is the single most important part of the diges-
tive system. it is here that the final breakdown or simplification of
food takes place. also, it is in the small intestine that digested
food enters the blood transportation system.
the small intestine is a muscular tube approximately twenty-three
feet long and an inch in diameter. it is located in the abdomen between
the stomach and large intestine and is held in place by a thin membrane
called the mesentery. the upper end of the small intestine is slightly
larger in diameter and is called the duodenum. it is in the area of the
duodenum that the digestive juices from the liver and pancreas enter the
small intestine.
the small intestine produces digestive juice of its own from spe-
cial cells in its walls. the digestive juice is called intestinal juice
and it contains several important enzymes. three of these, maltase,
sucrase, and lactase, finalize the breakdown of compound sugars, or di-
saccharides, into simple sugars. other enzymes, called pepidases, com-
plete the digestion of proteins into amino acids. the completely di-
gested food is now water soluble and the food molecules are simple, not
complex. in this form it can be carried by the blood stream and used
by all cells of the body.
the digested food passes from the small intestine into the blood-
stream through finger-like projections of the wall of the small intes-
tine called villi. the surfaces of the villi are covered with a net-
work of blood capillaries, or tiny blood vessels. all digested food
except fats enter these blood capillaries. (the fats pass through the
surface of the villi into a small branch of the lymphatic system. the
lymphatic system is a series of vessels which collect tissue fluid that
bathes the body cells. the fats make up part of this tissue fluid.) any
remaining water and undigested food, such as fiber, is passed on into
the large intestine.
questions

1. the tiny finger-like projections in the small intestine are called
2. digested proteins are called
3. digested food passes through the villi into tiny blood vessels

called

1. intestinal juice contains several important
2. what membrane holds the small intestine in place?

activities

1. locate diagram 2 on activity sheet 3. color the small intestine red

next, cut out diagram 2 and glue it to your display sheet. then,
label the small intestine.

1. locate diagram 7 on your display sheet. color the artery and

capillary network to the left of the slash marks red and the vein
and capillary network to the right of the slash marks blue. this
will indicate the change from oxygen-rich red blood to oxygen-poor
blue blood. color the villi yellow.

Explanation:

1. The text clearly states "the digested food passes from the small intestine into the blood stream through finger - like projections of the wall of the small intes - tine called villi".
2. It is mentioned that "other enzymes, called peptidases, complete the digestion of proteins into amino acids".
3. "The surfaces of the villi are covered with a net - work of blood capillaries, or tiny blood vessels. All digested food except fats enter these blood capillaries".
4. "The digestive juice is called intestinal juice and it contains several important enzymes".
5. "It is held in place by a thin membrane called the mesentery".

Answer:

1. villi
2. amino acids
3. capillaries
4. enzymes
5. mesentery