Chapter 12, Problem 18STP

Summary Introduction

To evaluate:

How nerve cells’ inability to divide after their formation might affect a person with spinal cord injury

Introduction:

A cell grows until it reaches its size limit, then it either stops growing or divides. Most cells undergo division. Cell division helps a cell to reproduce and makes the organism grow and heal certain injuries. Cells reproduce by a cycle of growing and dividing called the cell cycle.

Answer to Problem 18STP

A person with damaged spinal cord may suffer from paralysis as the nerve cells do not get replenished by cell division.

Explanation of Solution

Most cells undergo cellular division. Cell division prevents cells from becoming too large. It also helps an organism grow and heal certain injuries. Every time a cell cycle is repeated there is production of new cells. The result of continuous cell cycle is a continuous production of new cells. When some cells get damaged due to some injuries, the cell cycle produces new cells at the site of injury and the wound/ injury gets healed.

There is an exception to this rule. Nerve cells do not divide after their formation. They do not renew themselves. As a result of this, there is a loss of neurons after some years. If a person suffers a spinal cord injury, there is no way the damaged nerve cells will get renewed. So the person suffers from paralysis.

Scientists have been able to cure paralysis by using stem cells. These stem cells become nerve cells when transplanted into the site of a spinal cord injury. The new nerve cells replace the damaged cells.