Download Unit A - apel slice

SCIENCE Spin from WEEKLY READER
Technology
Saving Stephanie
Most kids love to eat pizza, hamburgers, and french fries. But until she was 8 years
old, Stephanie Singh couldn't eat any of those foods. In fact, she couldn't eat any
solid foods. Stephanie could be fed only through a tube inserted in her arm. Then
an amazing operation changed Stephanie's life.
Stephanie’s Favorite Foods
pizza
macaroni and cheese
homemade soups
Eating Through a Tube
Stephanie was born with visceral myopathy, a rare condition that doesn't allow the
intestine to develop properly. The intestines are a long tube made up of two main
parts. The first part, the small intestine, is connected to the stomach at one end.
Partially digested food flows from the stomach into the small intestine. The small
intestine absorbs nutrients from the food. Food that cannot be digested further
flows into the large intestine. The large intestine then eliminates the undigested
food waste from the body.
Because of her condition, Stephanie's small intestine couldn't break down food into
nutrients. Stephanie would have starved, even if she had eaten plenty of food. To
keep her alive,
Stephanie's doctors connected a tube to her arm. The tube delivered nutrient-rich fluids
directly into her bloodstream.
A Lifesaver
To help Stephanie, doctors performed an intestine transplant. Doctors perform many
different types of transplant operations, including heart, liver, and kidney
transplants. However, an intestine transplant is a risky and dangerous operation.
The intestine has special cells that protect a person's body from bacteria in food. When a
healthy intestine is put into a patient's body, the patient's immune system attacks
the transplanted organ. But those special bacteria-fighting cells in the intestine fight
the body's immune system. The cells fight one another, often causing the patient's
body to reject the transplanted organ.
After performing the operation, doctors gave Stephanie drugs to keep her immune
system from attacking the transplanted intestine. Since the operation, Stephanie has
been able to eat anything she wants.
---see diagram
Meet the Intestines
The intestine is a long tube made of two main parts. The first part, the small intestine, is connected
to the stomach at one end. Partially digested food flows from the stomach into the small
intestine. The small intestine absorbs nutrients from the food. Food that cannot be digested
further flows out of the small intestine into the large intestine. The large intestine eliminates
the food from the body.
The inside of the small intestine is lined by millions of villi. Villi are fingerlike projections that
increase the surface area of the small intestine. If the small intestine could be laid out on a flat
area, it would cover an area equal to a tennis court.
THINK ABOUT IT
1. How else is your immune system at work in your body?
2. Why would the human body fight to reject a transplanted organ?
Find out more! Log on to www.hspscience.com
59
SCIENCE Spin from WEEKLY READER
People
Back on BOARD
Bethany Hamilton is one tough kid. While she was paddling her surfboard in Hawaii, a
tiger shark ripped off Bethany's left arm below the shoulder. The 13-year-old
Hawaiian nearly died after losing more than half of her blood and undergoing hours
of surgery.
Doctors told Bethany that she survived the shark attack because she was in good
physical condition. All she remembers is lying on her board in clear water off the
island of Kauai. She did not see the 14-foot-long shark lurking nearby.
"My arm was hanging in the water, and [the shark] just came and bit me," Bethany said.
"I just held on to my board, and then it let go."
Doctors fitted Bethany with a prosthetic, or artificial, arm. Soon after, she learned to
snowboard in Colorado. Amazingly, less than three months after the attack, the
young surfing champion was back on the water in a local surfing competition. She
reached the finals of her age group, finishing in fifth place.
60
SCIENCE Projects
for Home or School
You Can Do It!
Quick and Easy Project
Materials
 plastic spoon
 zip-top plastic bag
 unflavored gelatin, prepared
 small rubber ball
 raisins
 marbles
Model an Animal Cell
Procedure
1. Use the plastic spoon to fill the bag about two-thirds full of gelatin.
2. Add the ball to the bag. What cell structure do you think the ball represents? What is
this structure's function in the cell?
3. Add raisins and marbles. Seal the bag tightly.
Draw Conclusions
Which cell structures do you think the raisins and marbles represent? What are these
structures' functions in the cell?
Design Your Own Investigation
Model a Plant Cell
Think about the differences between animal cells and plant cells. How might you
change your model of an animal cell so that it represents a plant cell? Choose
materials, and make a plant-cell model.
61