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Ok, I have been studying for my Bio test tomorrow, and I have to trying to find out what a Reflex Arx is, but I can't find it anywhere, so anyone know, and please describe it in detail.


Thanks
Storm

I typed Reflex Arc into Google and managed to get 63,000 hits.  

It is to do with Stimulus - Response in the CNS without higher reasoning being involved.  For example when you shine a light in your eye the pupil it contracts, you don't have to think about it.

What level are you studying at?

Will

I know that much, I looked in my book and searched on Google, but HOW does it do that? And I already know about the the weird word starting with the letter "G" thing, but I still don't know how does it accutally make that involuntary response.

OK, this is how I think of it and please remember I am not a Doctor or a physiologist or a biologist.

The Nervous system is a huge interconnected beast controlled by the brain, it is where all thought and movement come from.

The Reflex Arc systems use the same basic framework but are completely seperate from the CNS.

Let us take the finger in a flame reflex.  When you put your finger in a candle flame hundreds of nerve endings are affected, most of which are the pain ones.  Some are the specialised Reflex ones.

When a pain nerve ending is sparked it sends a message to the spine, the spine receives the message and sends it to the brain for processing.  The brain processes the information and you think "Ouch, what a silly bugger I am".

When a reflex nerve is sparked it goes along a similar but differant pathway.  On reaching the spine the message hits a specialist nerve whose whole purpose in life is to trigger a reflex and it sends messages back down nerves that fire off your arm muscles.

By the time your brain has received and processed the information you have already pulled your finger from the flame by reflex action.

Make sense?

Will

well, its 11 over here, and still going, and thanks sleep, it kind of made sense. I will understand all this by 8:55 by tomorrow, or I will fail that test, but the important thing is that we will find out which one it is.

Man, my brain is tired out, time to get some caffeine.

Thanks again sleep, what you said made alot more sense than the book.

please remember I am not a Doctor or a physiologist or a biologist.

Will

I don't think any person with "degrees" or "abbreviations" after thier name could have explained it more easily!
Well done!

No problems

Will (RN DipHE)

i was doin the exact same thing in biol about the same time.

a reflex arc is a monosynaptic reflex where for example the knee jerk reflex occurs.

sensory neurons in the patella tendon sense a stretch which sends this signal up the leg into the preganglion fibres, the nerve synapes onto a motor neuron in the spinal cord which then sends the message to the quadracept group of muscles and stimulates a contraction.

sorry its late!

..it all sounds very complicated to me... ...!

When I wake up in the morning my brain automatically detects the sphincter muscles in my colon, and says to me, "Hey Fozzer! You need a crap right now, otherwise it's going to be too late, and you are going to have a problem in the underpants department..."...!

It's as simple as that... ...!

LOL...LOL...LOL...!

Paul.