Why does the doctor test your Reflexes?

Summary

Podcast Summary: "Why does the doctor test your Reflexes?"

Who Smarted? – Educational Podcast for Kids
Host: Atomic Entertainment / Starglow Media
Release Date: April 8, 2026

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Episode Overview

This episode of "Who Smarted?" dives into the world of reflexes, exploring what they are, how they work, and why doctors test them (especially with that little rubber hammer on your knee!) Through silly experiments, roleplay, and interactive questions, hosts Adam Tex Davis and Chet Nickerson use humor to break down the science behind reflexes. Along the way, listeners learn how reflexes protect us, help us stay balanced, and even why you can't always control them.

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Key Discussion Points & Insights

What Are Reflexes?

• Definition & Examples:
  Reflexes are automatic body responses that happen without conscious thought in order to protect us.
  • Example: Ducking when something comes toward your face or sneezing when something irritates your nose.
• Instant Reactions:
  • Most reflexes occur without the thinking part of your brain (cerebral cortex) being involved.
  • Quote:

    "If you had to think every time you used your reflexes, we'd probably be in a lot of trouble."
    — Adam Tex Davis (02:54)

• The Reflex Experiment:
  To help explain, Adam uses "smarty magic" to make Chet go without reflexes, resulting in a banana cream pie incident!

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How Do Reflexes Work?

• The Nervous System & Spinal Cord:
  Reflexes are managed by the nervous system—sensory nerves detect dangers, and the spinal cord directs muscles to react instantly.
  • Quote:

    "When sensory nerves in your body...detect something startling, like a loud noise or a pie flying toward you, your nervous system instantly directs muscles to react before the thinking part of your brain knows what's happening."
    — Adam Tex Davis (04:49)

• Spinal Cord Role:
  • The spinal cord controls many reflexes, especially in your arms and legs, acting as a shortcut for fast responses.
  • Quote:

    "It's A, the spinal cord. With the spinal cord running down your back, it can quickly control most of your body's muscles and trigger reflexes."
    — Adam Tex Davis (05:37)

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Why Do Doctors Tap Your Knee? (The Knee-Jerk Reflex)

Demonstration & Explanation:

• The doctor taps the tendon below your kneecap to stretch it, which sends a message through the spinal cord causing your leg to kick out—an example of a "deep tendon reflex" (DTR).
  • Quote:

    "The doctor is using the hammer to cause your tendon and a connected thigh muscle to stretch. The stretch alerts your spinal cord, which reacts by contracting the muscle, causing you to kick."
    — Adam Tex Davis (12:51)

• Purpose:
  • This check ensures your nervous system is healthy and that your reflexes are responding as they should.

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Other Surprising Reflexes

• Blinking & Eye Movements:
  • When you move your head but keep looking at something, your eyes move in the opposite direction to keep your vision steady.
  • Quote:

    "When your head went right, your eyes went left. And when your head went left, your eyes went right. This eye reflex is essential for stable vision, since your head moves all the time."
    — Adam Tex Davis (11:50)

• Sneezing & Coughing:
  • Both are reflexes designed to clear irritants from your airways.
• Protective Reflexes:
  • Pulling your hand away from something hot before you even feel the pain.

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Why Reflexes Are Important

• Protection:
  Reflexes protect us from harm by acting faster than conscious thought.
  • Quote:

    "Reflexes allow you to get away fast before something can hurt you too badly."
    — Adam Tex Davis (08:39)

• Movement & Balance:
  Reflexes help you balance, stand, walk, run, and keep from falling.
• Sometimes the Brain Steps In:
  Occasionally, your thinking brain can override a reflex if there’s even a split-second of extra time (like saving a lemonade pitcher from breaking during a fall).

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Notable Quotes & Memorable Moments

• On Life Without Reflexes:

  "Ah, yes. I have cream all over my face and a bit in my eye and some in my nose. It's deliciously uncomfortable."
  — Chet Nickerson (03:45)

• On Reflex Purpose:

  "You said A. You're right. Reflexes protect your body."
  — Adam Tex Davis (07:52)

• On Eye Reflex:

  "Your eye reflex is essential for stable vision, since your head moves all the time. And without this reflex, you'd have blurry vision and trouble reading, especially while walking or running."
  — Adam Tex Davis (11:50)

• On Doctor's Reflex Test:

  "This reflex keeps you standing because it reacts to the pull of gravity on your knees. It's called a deep tendon reflex, or dtr."
  — Adam Tex Davis (13:33)

• On Occasional Brain Intervention:

  "If there's enough time and I'M talking, like, just an extra split second, your brain might jump in and take back control."
  — Adam Tex Davis (14:19)

• Funny Finale:

  "What? And miss out on all this delicious banana cream pie? Mmm. Delicious."
  — Chet Nickerson (15:02)

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Timestamps for Important Segments

• Introduction to Reflexes: 00:31–02:19
• What Happens Without Reflexes (Chet’s Pie Incident): 03:18–04:44
• Role of Spinal Cord and Nervous System: 04:44–06:01
• Sneezing and Coughing as Reflexes: 06:26–07:15
• Role of Reflexes in Protection: 07:27–08:39
• Reflexes in Movement and Balance: 08:39–09:20
• Eye Reflex Experiment: 11:02–12:18
• Doctor’s Knee Test Explained: 12:25–13:55
• When the Brain Overrides Reflexes (Lemonade Story): 13:59–14:45
• Episode Wrap-Up: 14:45–15:11

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Summary in a Nutshell

This "Who Smarted?" episode delivers a fast-paced, laugh-out-loud, and interactive look at reflexes. From silly scenarios to practical science, listeners discover:

• Reflexes are automatic and mostly run on “autopilot” via the nervous system and spinal cord.
• They serve to protect and help us move, often acting faster than our conscious mind.
• Doctors check reflexes (like the knee-jerk) to make sure our brains and bodies are communicating correctly.
• Some reflexes (blinking, sneezing, and even eye movements) are surprising but crucial.
• Sometimes your thinking brain can step in if there’s enough time to “override” a reflex.

Whether you’re a kid or a parent, you’ll finish this episode knowing exactly why you kick when the doctor taps your knee—and why that’s such a smart thing!

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Perfect for classroom discussion or family listening, this episode packs both giggles and “aha!” moments into a memorable science lesson on how your body keeps you safe—before you even know it.

Transcript

[Jane Lindholm]

Kids, you have a lot of questions.

[Adam Tex Davis]

Is a crocodile a dinosaur?

[Chet Nickerson]

Why do people vote?

[Adam Tex Davis]

How does your food turn into your poop?

[Jane Lindholm]

But why? A podcast for curious kids has answers. I'm Jane Lindholm. Join me as we dig deep into everything from science to history, nature, emotions, and sometimes even the weird.

[Chet Nickerson]

Why are jellyfishes made of jelly? Or are they made out of jelly?

[Adam Tex Davis]

Find.

[Jane Lindholm]

But why? Wherever you get your podcasts.

[Adam Tex Davis]

And now it's time for who Smarted? Psst. Hey, smarty pants. Today we're going to talk about something that some of you might know, but some of you might not. And that is. Hey, look out behind you. Did you turn to look? Anyway, as I was saying, today we're talking about.

[Chet Nickerson]

Whoa.

[Adam Tex Davis]

Watch your head. Did you duck? No, not that kind of duck. I mean, did you quickly drop your head or put your arms up to protect yourself? Maybe some of you did, but most of you probably didn't, because you know you're listening to a podcast. But if it was someone nearby who yelled that out, chances are you would. And that's a good thing, because that would mean your reflexes are working. Yep, today we're talking about reflexes and how they keep you safe. But how do they do that? To help demonstrate, I'm joined by my friend, favorite newscaster and bagel store owner, Chet Nickerson.

[Chet Nickerson]

Hiya, folks. Chet Nickerson here, ready to report on reflexes.

[Adam Tex Davis]

Great. Now, by using a little smarty magic, Chet will experience what life would be like without reflexes.

[Chet Nickerson]

Yes, that sounds like a great idea and lots of fun. After all, how important could reflexes be anyway?

[Adam Tex Davis]

What do you think, smarty pants? Why do we have reflexes? How do they work? What are some surprising ones? And why do doctors check your reflexes by tapping your knee and making your leg bounce up?

[Chet Nickerson]

I don't know, but I sure love when they do that. In fact, I even do that to myself with my microphone when nobody's watching.

[Adam Tex Davis]

Oh, boy. I think Chet's in for a world of exciting discoveries and a little pain. As for you, smarty pants, get ready for another whiff of science and history on the smart.

[Chet Nickerson]

Who's smarted? Who's smart? Is it you? Is it me? Is it science or history? Listen up, everyone. We make smarting lots of fun. But who's smart?

[Adam Tex Davis]

And hey, smarty pants, chances are something will happen today that will cause your reflexes to spring into action. Do you even have to think about your reflexes? Yes or no? The answer is no. That's because most of your reflexes work without your brain.

[Chet Nickerson]

Whoa.

[Adam Tex Davis]

If you had to think every time you used your reflexes, we'd probably be in a lot of trouble. Speaking of, let's bring back our good friend Chet Nickerson.

[Chet Nickerson]

Yes, here I am, completely unsuspecting and not ready for anything.

[Adam Tex Davis]

Great. Now remember, Chet has unwittingly agreed to go without reflexes, using a little smarty magic.

[Chet Nickerson]

That's right. And I am ready to report on my findings.

[Adam Tex Davis]

Indeed. Okay, for our first test, I'm gonna throw a banana cream pie at your face.

[Chet Nickerson]

Uh, what now? Hey, why are you holding up that pie? Say, is that banana cream? Yep, it sure is. Yummy.

[Adam Tex Davis]

As you can hear, Chet barely reacted to being hit in the face with the piece.

[Chet Nickerson]

Ah, yes. I have cream all over my face and a bit in my eye and some in my nose. It's deliciously uncomfortable.

[Adam Tex Davis]

So, smarty pants, can you tell me what happened to Chet? A, without reflexes, his muscles stopped working. B, without reflexes, his brain had to figure out what was happening and couldn't react in time. Or C, without reflexes, his body embraced the pie and might even want more.

[Chet Nickerson]

Um, I don't know about that last one.

[Adam Tex Davis]

What's that? C, you say? Okay.

[Chet Nickerson]

Twice. Twice.

[Adam Tex Davis]

Sorry. Chat. It's all for science.

[Chet Nickerson]

Luckily, it's quite tasty. But I truly hate having cream pie up my nose.

[Adam Tex Davis]

Smartypants, the correct answer to the previous question was actually B. Without reflexes, your brain would have to think about everything that's happening around you. And if you take time to think about it, you probably won't react fast enough. Just like Chet here with the pie.

[Chet Nickerson]

Does anybody have a towel?

[Adam Tex Davis]

When you have reflexes, another part of your body acts instead of the thinking part of your brain, causing a much faster reaction. Smartypants, do you know what part of the body directs reflexes? Is it A, the stomach, B, the muscular system, or C, the nervous system? If you said C, great job. When sensory nerves in your body, the ones that can touch, see and hear, detect something startling, like a loud noise or a pie flying toward you, your nervous system instantly directs muscles to react before the thinking part of your brain knows what's happening. And, smarty pants, do you know what part of your nervous system is usually in charge of reflexes? Is it, A, the spinal cord, B, the pituitary gland, or C, the nose?

[Chet Nickerson]

The answer is, please don't say nose.

[Adam Tex Davis]

Nope. It's A, the spinal cord. With the spinal cord running down your back, it can quickly control most of your body's muscles and trigger reflexes especially in your arms and legs. Reflexes are your body's automatic shortcut to reacting quickly. And wouldn't you know, you've had most of them since you were born. Well, except for Chet here for the moment.

[Chet Nickerson]

You know, I think I'd like my reflexes back.

[Adam Tex Davis]

Please, smarty pants. True or false? The word reflex comes from a Latin word meaning reflection. The answer is true. And yes, Chet, you can have your reflexes back.

[Chet Nickerson]

Thank you. Phew. That's much better. I hated having all that banana cream pie in my nose.

[Adam Tex Davis]

Smarty pants, yes or no? Is a sneeze a reflex? If you said yes, you're right.

[Chet Nickerson]

Oh, good. So that means I definitely have my reflexes back.

[Adam Tex Davis]

Yes, and as I'm sure you know, a sneeze is a reflex that clears bothersome things out of your airways.

[Chet Nickerson]

Like banana cream pie.

[Adam Tex Davis]

Exactly. Coughing is a similar reflex. Smartypants, what other reflexes should spring into action if something comes flying at you? Go ahead, shout out your answers.

[Chet Nickerson]

Ooh. For one thing, I would try to duck. No, not that kind of duck. Oh. I'd also put out an arm to try to block the pie from hitting my face.

[Adam Tex Davis]

Great. But what if you couldn't block it?

[Chet Nickerson]

Well, then more sneezing?

[Adam Tex Davis]

Sure, but before that, your face would scrunch up as you brace for the impact. And you'd probably close your eyes to keep PI from getting in them.

[Chet Nickerson]

Aha. You're right. So those are reflexes, too.

[Adam Tex Davis]

They sure are, smartypants. Why do you suppose we have reflexes instead of letting the brain think through everything? Is it because A, reflexes move faster to protect you? B, reflexes help you move and do physical activities? Or C, reflexes are nerves secretly trying to take over your body and do

[Chet Nickerson]

away with your brain? Yikes.

[Adam Tex Davis]

Fortunately, the answer is not C. You said A. You're right. Reflexes protect your body. Hear that? I just boiled water for some hot chocolate. Say, Chet, want to remove your reflexes again and see what happens when you grab the kettle?

[Chet Nickerson]

Do I have to?

[Adam Tex Davis]

Only if you can tell me what would happen, smarty pants. Do you know?

[Chet Nickerson]

Well, without reflexes, I would just grab the hot kettle handle and burn my hand. Ouch. But with reflexes, as soon as I touch the hot handle, I'd pull my hand away before I got badly burned.

[Adam Tex Davis]

What do you think, smarty pants? Did he get it right? He sure did. Great job, Chet.

[Chet Nickerson]

Now, about that hot chocolate. Ooh, delish.

[Adam Tex Davis]

Reflexes allow you to get away fast before something can hurt you too badly. But reflexes do more than just that. Remember my earlier question asking why we have them? Well, there was more than one correct answer. Reflexes also help you move and do physical activities. Heads up.

[Chet Nickerson]

Chat. Aha. I ducked under the basketball. Grr. But I spilled my hot chocolate. Guess I'll have to make more. Ow. It's still hot.

[Adam Tex Davis]

Anyway, like I was saying, reflexes help your body move. And that test your doctor does tapping your knee with the little hammer has something to do with it.

[Chet Nickerson]

Oh, yeah? What's that?

[Adam Tex Davis]

I'll tell you right after this quick break. And a word from our sponsors. Spring is here, and if you're a homeschool family trying to finish the year strong, I want to tell you about ixl. It's the award winning online learning platform that fits seamlessly into your homeschool routine, covering math, language arts, science and social studies from Pre K through 12th grade. What I love most about IXL is how it adapts to each child's pace. Whether your kid needs to reinforce foundational skills before an assessment or push ahead into new material, IXL meets them exactly where they are. With no pressure and real encouragement built right in. Kids earn rewards, see their own progress, and actually feel good about learning. And for parents, the real time progress tracking is a game changer. You always know exactly where your child stands. Plus, it makes learning fun. And you know, I love that. Over 15 million students use IXL and it's proven to improve achievement in all 50 states. So make an impact on your child's learning. Who smarted? Listeners get an exclusive 20% [e-mail] smarted that's ixl.com smarted for your 20% off. Now back to who smarted. Okay, smarty pants, let's try out a reflex right now. One you might not even realize you have. I want you to look at something in front of you and and focus on it. It could be a book, a smartphone, a tree, your teacher, a chair, the person driving the car you're in, anything.

[Chet Nickerson]

How about this pineapple?

[Adam Tex Davis]

Sure, a pineapple works as long as you don't put it on pizza. Now, I want you to keep looking at that thing, but as you're doing it, shake your head. Not too crazy, but keep moving as you focus on the thing in front of you. Are you doing that now? Well, guess what? You're using a reflex.

[Chet Nickerson]

Whoa, whoa, whoa. Stop the presses. This reporter knows a thing or two about reflexes, and I think you're wrong.

[Adam Tex Davis]

Oh, really, Chet? How so?

[Chet Nickerson]

You said reflexes act without you thinking about it. But I did think I thought about focusing on something and shaking my head.

[Adam Tex Davis]

Ah, yes, but did you think about your eye movement?

[Chet Nickerson]

My eye movement, you say? Hmm.

[Adam Tex Davis]

Smartypants, while you were shaking your head, you were also moving your eyes in the opposite direction, probably without realizing it. When your head went right, your eyes went left. And when your head went left, your eyes went right. This eye reflex is essential for stable vision, since your head moves all the time. And without this reflex, you'd have blurry vision and trouble reading, especially while walking or running.

[Chet Nickerson]

Interesting. I'm glad you didn't take that reflex away. I don't like feeling woozy.

[Adam Tex Davis]

Other reflexes help make walking and running possible, too. Let me demonstrate. Chet, would you mind sitting on this table?

[Chet Nickerson]

Oh, boy. Be gentle.

[Adam Tex Davis]

Don't worry, I won't take away your reflexes. Instead, I have one of those small rubber hammers we've all seen at the doctor's office. Would you mind if I tap your knees with it? It won't hurt, I promise.

[Chet Nickerson]

Sure, go for it. Hey, there goes my leg kicking up into the air. And now there goes my other leg. But wait, I didn't kick my legs out on purpose.

[Adam Tex Davis]

You did that, smarty pants. Has your doctor ever done this to you before? So why does your leg jump out? Is it because A, the hammer's vibration causes it, B, the doctor is hitting your knee at a specific speed, or C, the doctor is hitting a tendon? The answer is C. The doctor is using the hammer to cause your tendon and a connected thigh muscle to stretch. The stretch alerts your spinal cord, which reacts by contracting the muscle, causing you to kick.

[Chet Nickerson]

But I don't understand, unless I'm playing soccer, what's so important about this reflex of kicking?

[Adam Tex Davis]

Well, for one thing, without it, you'd likely fall down a lot. This reflex keeps you standing because it reacts to the pull of gravity on your knees. It's called a deep tendon reflex, or dtr. Your doctor checks it to make sure your nervous system is healthy. If you kick, that means this reflex and your other reflexes are working just fine.

[Chet Nickerson]

Aha. And then you never have to think about them.

[Adam Tex Davis]

Smarty pants. Is that true? Believe it or not, sometimes your thinking brain does assist with a reflex. For example, Chet, say you're carrying a glass pitcher of ice cold lemonade to your friends, and suddenly you trip. Now, normally, your reflexes would cause you to put out your arms to break your fall, but that would mean you had to toss the lemonade pitcher. However, if there's enough time and I'M talking, like, just an extra split second, your brain might jump in and take back control. If it doesn't look like you're going to be too badly hurt in the fall, your brain may have you protect the pitcher with your arm. You might get a little more sore.

[Chet Nickerson]

Oof.

[Adam Tex Davis]

And you'd probably spill some lemonade, but you wouldn't smash the pitcher.

[Chet Nickerson]

Ah, that was a close call. But thanks to my reflexes, I can still drink the rest of the lemonade. You know, I don't think I'm gonna agree to give up my reflexes from now on.

[Adam Tex Davis]

Good idea, Chet. Think fast. Hey, Chet, you didn't even move.

[Chet Nickerson]

What? And miss out on all this delicious banana cream pie? Mmm. Delicious.

[Adam Tex Davis]

Double shout out. To Rowan and Clara in Chicago, Illinois. Thanks so much for writing to tell us how you listened to who Smarted every morning during breakfast and and in the car all the time. You love learning new things while having fun. Oh, and you also love our Netflix show Brainchild. Aw, thanks, you guys. We're so happy to have you smarting and brainchildling with us this episode. Reflexes was written by Dave Beaudry and voiced by Adam Chet Davis and Jerry Colber. Technical direction and sound design by Josh Hahn. Our associate producer is Max Kamasky. The theme song is by Brian Suarez with lyrics written and performed by Adam Tex Davis. Who's Smarter was created and produced by Adam Tex Davis and Jerry Colbert. This has been an Atomic Audio production.