Action potential and strength of muscle contraction?

[sameeralord]

Hello guys,

Although the response of a motor unit is all-or-none, the strength of the response of the entire muscle is determined by the number of motor units activated. Nerve impulses passing down a single motor neuron will thus trigger contraction in all the muscle fibers at which the branches of that neuron terminate. and this is a motor unit.

1.My question is some organs are supplied only with one motor neuron, is it impossible for them to control the strength of their contraction?
2.Also this is just about the central nervous system. Since CVS has many nerves which are branches of other nerves, when an action potential is sent how come this action potential doesn't travel through the branches and innervate unnessecary structures?

Thanks for anyone who is going to help

 

[somasimple]

1/ No.
2/ idem.

 

[Moonbear]

I think you're confusing the terms nerve and neuron.

A nerve is a bundle of neuron axons (surrounded by endoneurium, perineurium and epineurium, which are connective tissue layers that hold them together). You don't have a single NEURON innervating an organ, but you may have a single NERVE innervating it, with MANY neurons.

Also, as soon as you're talking about nerves, by definition, you're talking about the peripheral nervous system, not the central nervous system, so your second question doesn't make sense to me.

 

[sameeralord]

I think you're confusing the terms nerve and neuron.

A nerve is a bundle of neuron axons (surrounded by endoneurium, perineurium and epineurium, which are connective tissue layers that hold them together). You don't have a single NEURON innervating an organ, but you may have a single NERVE innervating it, with MANY neurons.

Also, as soon as you're talking about nerves, by definition, you're talking about the peripheral nervous system, not the central nervous system, so your second question doesn't make sense to me.

Yes you are absolutely correct. I went back and read from scratch about nerves,neurones and connective tissue you talked about and worked it out. Thanks for the help

 

[LudusRex]

Hello,

To answer your first question, while it is true that some organs are supplied with only one motor neuron, the strength of their contraction can still be controlled through the recruitment of additional motor units. This means that as the demand for stronger contraction increases, more motor units will be activated to produce a greater force.

As for your second question, the action potential travels down the specific nerve that is connected to the motor unit responsible for innervating the desired structure. The branching of nerves allows for more precise control over which structures are innervated and activated. Additionally, the nervous system has mechanisms in place to prevent unnecessary activation of structures, such as inhibitory signals that can prevent action potentials from reaching certain nerves. This helps to ensure that only the necessary structures are activated.

I hope this answers your questions. If you have any further inquiries, please feel free to ask. Thank you.