There are lots of things kids don’t like about doctor’s visits; shots, blood tests and throat swabs top the list. One thing they love is having their knee reflexes checked.
A reflex is an involuntary, rapid muscular response to a stimulus, or something that causes a reaction. The nervous system helps our body perform two types of actions: those that we can control and those that we can’t. An example of the former is the way my fingers are typing this article. An example of the latter is the way my intestines are digesting the turkey sandwich I ate for lunch an hour ago. Reflexes are actions we can’t control.
Most reflexes protect the body. They are coordinated by nerves that go to and from the spinal cord without the brain’s direct involvement. Here are a few of them.
Deep-tendon reflex: When the tendon below your kneecap is tapped in the right spot, it’s briefly stretched. During the stretch, a signal is sent to the spinal cord. The signal returns to the thigh muscles, causing them to contract and your leg to jump. It’s fun to experience because your leg appears to jump on its own. It’s like a magic trick.
