This blog is going to teach you all about reflexes. What a reflex is, a little bit of history about how we know so much about them, and what you can expect from them as time goes on! We’ll also go over some different reflexes and their functions. So grab your workbook and get to it!
The dictionary defines “reflex” as “a reaction or response that occurs involuntarily.” When you step on an object with your bare foot, the nerves in the sole of your foot send signals up through your spinal cord and into your brain telling it where the pain is coming from. This signal to make this involuntary response to pull away is called a “reflex. “
Do you know which reflex is triggered when a stranger suddenly grasps your arm?
Reflexes were first discovered in the mid-1800s. A French scientist named G.B. Duchenne made a revolutionary study of human reflexes. He was one of the first individuals to use electrical shocks as a way of measuring neural responses in humans.
Duchenne’s studies on electro-physiology led him to discover many important facts about the reflexes in humans, animals, and even plants!
Here some points are discussed-
1. What are our reflexes?
Reflexes are actions that we can’t control, because they are controlled by the autonomic nervous system (ANS). The ANS is the part of the nervous system that controls the unconscious parts of our bodies.
It controls things like blood circulation and breathing. A great example of a reflex is when we sneeze. When you first feel that tickle in your nose, you can’t stop it from happening. That’s because it’s a reflex, and your brain doesn’t tell your body to sneeze to keep you safe!
2. When do they work?
Some reflexes work every time, but others aren’t as reliable. Some things that trigger a reflex are injury, illness, or pain. For example, when you get injured, it triggers a reflex to protect your body from the injury. An example of this is when the brain tells your arm to bend backward to protect your head from an oncoming baseball bat!
3. How do we know all this?
The French scientist Duchenne was able to study human reflexes because his special instruments could measure electricity in the spinal cord and in specific nerve centers called nuclei.
He was able to discover that by stimulating certain areas of the spinal cord (nuclei) with electrical waves one could make different parts of the body move without moving their own muscles. Another great example of this is when the body tells the arm to bend backward to protect your head, or when it tells you to sneeze.
4. What is a reflex arc?
The reflex arc is a diagram that shows how our body responds to stimuli. It’s a pretty big picture idea, but if you break it down into smaller parts, here’s what it looks like:
In this picture the red box acts as “the brain” and the green box represents “the body.”
When an electrical impulse travels through one part of the nerve cell (dotted line), that impulse triggers another nerve cell (shown in red) which then sends its own electrical impulses (or a chemical signal). These impulses travel back to the brain and the brain interprets that information. It’s not as complicated as it looks!
5. What are some examples of reflexes?
The most common types of reflexes are:
This instinctual response is one that you probably use every day without even thinking about it. It’s what makes your hand move to cover your mouth when you sneeze or cough, and even makes it hard to talk while you’re vomiting!
The classic knee jerk is the most well known example of a monosynaptic reflex. If a doctor taps the tendon below your knee cap with a small rubber hammer, it will cause your leg to immediately jerk up. When the doctor taps your knee cap, it gives off an electrical message that travels from your body to the brain. Then, in about one tenth of a second, it triggers a response in your muscles (because you don’t consciously tell them to move).
6. How do we study reflexes?
Scientists measure the speed of a reflex by using electromyography (EMG) and electroencephalography (EEG). EMG records the electrical activity of muscles; EEG records the brain’s electrical activity in response to sensory stimuli. By combining these two methods, scientists have been able to discover how quickly a reaction occurs!
7. How has our understanding of reflexes changed since the 1800s?
When the French scientist Duchenne first discovered human reflexes, he made an assumption that he soon came to realize was wrong. When humans are exposed to something that triggers their reflex, we can’t consciously control it.
