Muscle Tissue

[somebody]

Hey guys, just came across my reading that skeletal muscle is one kind of mucle tissue and i do not understand the part where my book says that it is controlled voluntarily. And cardiac muscle are controlled involuntarily.

Can some one make sense out of this please.

[InfiniteNow]

Originally Posted by somebody

Hey guys, just came across my reading that skeletal muscle is one kind of mucle tissue and i do not understand the part where my book says that it is controlled voluntarily. And cardiac muscle are controlled involuntarily.

Can some one make sense out of this please.

Involuntary muscles tend to be controlled at the point where the spine, brain stem, and cortex come together. These generally govern survival mechanisms for us without need for focus and thought. For example, you do not need to think to take a breath every time or you don't have to think about making your heartbeat. Hence, it's involuntary muscle.

However, your arms don't just start moving on their own. You generally need to think to do it. It's a whole complex interaction of different parts of the brain (motor cortex, prefrontal executive function, inner parts ensuring proper balance and so forth) all working in harmony which make you, for example, reach out and pick up the glass of water in front of you. Those are the voluntary muscle movements.

Although we can get really good at tasks which are repeated often, and don't have to think much about it to engage in those tasks (like walking for example), we still voluntarily triggered our body to make the motions.


Hope that helps a little.


Cheers.

[ughaibu]

Are movements of, for example, the arms during sleep considered to be voluntary or involuntary?

[InfiniteNow]

Originally Posted by ughaibu

Are movements of, for example, the arms during sleep considered to be voluntary or involuntary?

Interesting question, ughaibu. My thought is that the movements themselves are involuntary, however, they are controlled by muscles that would be considered voluntary.

However, regardless of the accuracy of my response, you can certainly learn more about the process by checking out the following:
http://en.wikipedia.org/wiki/Rapid_eye_movement


"Sleep is food for the brain." - One of my instructors back in the day.

[InfiniteNow]

Upon further reflection, I realized I misspoke above. Bodily movements would occur during non-REM sleep, particularly stage 4 where parasomnias occur.

http://en.wikipedia.org/wiki/Parasomnia


Sorry for the confusion. I am just really fascinated by REM sleep and it's various explanations...

[somebody]

Thanks guys great examples (better than my book). i apreciate it.

[gribbon]

The bit about invoulountary movement is correct, but to make this bit more specific I'll write something...

It's a whole complex interaction of different parts of the brain (motor cortex, prefrontal executive function, inner parts ensuring proper balance and so forth) all working in harmony which make you...etc

It's the "efferent leg" of the peripheral nervous system which conveys commands to the muscles and glands, and is takes responsibility for voluntary movement.

The efferent leg of the peripheral nervous system is responsible for conveying commands to the muscles and glands, and is ultimately responsible for voluntary movement. Nerves move muscles in response to voluntary and autonomic (involuntary) signals from the brain, and "deep muscles" as well as "superficial muscles", muscles of the face and internal muscles all react to regions of the primary motor cortex of the brain, which I think is directly in front of the central sulcus that seperates the frontal and parietal lobes...Not sure about the last bit though...

[Taraxanoid]

Well, some call it involuntary and voluntary muscular movement, but I like to call it subconscious and conscious movement.

[Racoon]

As far as cardiac muscle being involuntarry, thats becuz' a crucial 1% of heart muscle cells do not contract, and function as the 'cardiac conduction system'.

These include self-excitatory pacemaker cells. They spontaneously produce and conduct the electrical impulses that stimulate the contraction.

Thanks to this conduction system, even if all nerves leading to the heart are severed, the heart will keep right on beating!

Kinda' like when the evil priest ripped out the human sacrifices heart in Indiana Jones and the Temple of Doom!