023 How Reflexes Work (Knee jerk and eye blink)

[Skate2bate]

remote control... SOOO GHETO HAHAHAHA

[memyselfq80]

you are one of the best ...thank you so much >>

[hoychris]

why are reflexes useful to a clinician for diagnosis?

[InteractiveBiology]

@hoychris Thank you for watching the video. Unfortunately, Leslie is busy at the moment working a lot on improving the site. He is unavailable to answer any questions. We do have a Facebook fan page where you can interact with other readers and get answers to your questions. In the meantime, stay tuned because we have more Biology videos coming very soon!

[tewolde33]

what if you hit your knee and then does not move

[InteractiveBiology]

@tewolde33 All questions are answered in the Interactive Biology forums from now on. Go to the website in the description and then visit the forum. This is to make it as efficient as possible as we have multiple people over there to help answer questions.

All the best

[hollytom1]

Whoa. Tutor Tom has it backwards. The dorsal horn is SENSORY and receives AFFERENT impulses. The ventral horn is MOTOR and sends EFFERENT impulses.

[ilikedatube]

Press 1:00 repeatedly (sexy ooohh)

[TutorTom10]

@InteractiveBiology Yes, you are quite right; I suppose it's important not to get too carried away with the details but stay more focused on the basics of the concept. Please keep making more videos, these are great!

[TutorTom10]

@InteractiveBiology Also, I think you may have mixed up the dorsal/ventral roots and horns; the efferent neuron should enter the dorsal horn and travel along the dorsal root, c.f. the afferent neuron soma should be in the ventral horn and exit via the ventral root. And (not to be picky) but isn't fine movement control more to do with the ratio of motoneurons:muscle fibres, i.e. size of motor units?

[InteractiveBiology]

@TutorTom10 Not sure what I said about dorsal/ventral roots, but my focus wasn't the anatomy - just the physiology. Also, you are right about fine motor control. However, I wasn't dealing with fine motor control in this video. With the eye blink reflex, I was dealing with the ability to stop that reflex from happening. You have more control of the process because there is an interneuron that can be overridden. You have no control over the knee-jerk reflex.

[tieu589]

the purpose of the absence of interneurone in knee-jerking(in the movement pathway) is to shorten the time for impulse to be transmitted from receptor to effector right? but what's the purpose for the reaction to be performed so fast since it doesn't causes us harm at all? on the other hand, reflex arc which we perform when we accidentally touch anything sharp or hot has interneurone between the afferent and efferent neurone,wouldn't it take more time for us to react and worsen the injury? > <

[InteractiveBiology]

@tieu589 That's a good question, and I'm not sure WHY it is that way. I do know that it gives us info about the health of certain aspects of our nervous system, but not sure what the function is besides that. A reflex involving removing your hand from a hot stove makes complete sense, but this one - I don't know.

[TutorTom10]

@tieu589 @InteractiveBiology It is because this reflex performs an important role in keeping balance and posture, e.g. think about jumping - when you land, your thigh muscles will stretch but instead of staying relaxed they (nearly) spontaneously contract to compensate and stop you from falling flat on your face! But this reflex also occurs on a less extreme (yet equally important) scale in such mundane tasks as walking and getting out of bed.

[InteractiveBiology]

@TutorTom10 That makes perfect sense. Thanks for adding that bit of info. Good stuff!

[TutorTom10]

P.S. Awesome channel man; great stuff! (Would appreciate any feedback you could give for some of my attempts at videos of a similar nature, you seem like an experienced teacher!)

[InteractiveBiology]

@TutorTom10 Just checked out your channel and got excited. Great to see someone else doing some similar things. We should connect sometime. Maybe via skype.

[TutorTom10]

@InteractiveBiology That would be awesome! I'll send you a private message so we can chat more.

[tieu589]

I would like to ask something...why don't we need an interneurone in between the afferent neurone and efferent neurone? doesn't our brain need to be notify about the knee jerk action we just did?

[InteractiveBiology]

@tieu589 Yes, the brain is notified. However, that's a totally separate pathway with interneurons involved. The simple reflex arc shown here just gets the muscles contracting. Other pathways go to the brain and the brain interprets those signals.

[jannna92]

so there is no inter neurons present in the knee jerk reaction?.. 

[InteractiveBiology]

@jannna92 That is correct. That's why you can't control it :)

[madej1858]

such a good teacher i cant believe i understand reflex in 8 MINS... i spend weeks reading and didn't understand to much.. But now i understand that reflex have interneuron which means that you have more control. no internueuron you have no control over it......

[InteractiveBiology]

@madej1858 That's Awesome. I'm so glad that I'm able to make it easier to understand for you. Sometimes, it just takes someone breaking it down in a simple way for you to understand it. Stay tuned, because there's a lot more coming :)

[haseebs123]

Your the best thank you very much, very good demonstration!

[InteractiveBiology]

@haseebs123 Thank you. Glad you found value. Make sure to subscribe to be notified of future videos :)

[ExpertSwimmer]

when you do the knee reflex test you can put your hand on the leg muscle and feel the contraction. 

[InteractiveBiology]

@ExpertSwimmer That's correct. It's such a cool response :)

[ExpertSwimmer]

Thank you for shearing and buy the way you really can't control the knee reflex. I want to ask you why not everyone have the knee jerk reflex? Because when I did it to someone in my class mostly the girls have more knee jerk the boys. And just let you know when no jeans is on the leg you get a better knee jerk and higher kick. And don't stand in front of anyone when doing the might kick you. There are people have more knee jerk then others. But thank you and post more if you can. Keep it up!

[InteractiveBiology]

@ExpertSwimmer You are very much welcome. Yes, I will be definitely posting more. I intent to post one every weekday. Didn't do one today because it has been kinda hectic, but more is definitely coming :)

Thanks for checking out my channel and I'm glad you found value in it :)