Question

Explain why you would have expected skeletal muscle to be voluntary, but smooth muscle and cardiac muscle to be involuntary. (pages \(69-70\) )

Short answer

Skeletal muscles are voluntary because they enable us to perform actions that require conscious thought and control, such as walking and eating. In contrast, smooth and cardiac muscles are involuntary because they perform vital functions that need to occur consistently and constantly, such as pumping blood and moving food through the digestive system. It would be highly impractical and dangerous if we had to consciously control these functions; they must occur automatically without the need for us to think about them.

Step-by-step solution

Understand differences between muscle types

Skeletal muscles are attached to bones and help us move our bodies. They are under conscious control, meaning that we can decide when to use them. In contrast, smooth muscles are found in the walls of hollow organs like the stomach and cardiac muscles are present only in the heart. They perform involuntary movements, meaning that they work without us consciously directing them.

Explain why skeletal muscles are voluntary

Our skeletal muscles are voluntary because they enable us to perform actions that require conscious thought, such as walking, writing, and eating. We have full control over how and when we move these muscles. They enable us to respond to our environment in ways that require deliberate, conscious thought and planning.

Explain why smooth and cardiac muscles are involuntary

The movements of both smooth and cardiac muscles are typically involuntary, meaning they function without conscious thought. This is because these muscles perform vital functions that need to occur consistently and constantly, such as pumping blood through the body (in the case of cardiac muscle), or moving food through the digestive system (in the case of smooth muscle). It would be highly impractical, even dangerous, if we had to consciously control these functions. They must occur automatically, without the need for us to think about them.

Summarize the reason

The key reason why skeletal muscles are voluntary and smooth and cardiac muscles are involuntary boils down to the types of tasks they perform. Skeletal muscles are responsible for tasks that require conscious thought, while the smooth and cardiac muscles execute tasks that need to continually happen without interruption or conscious direction. This understanding helps us appreciate the intricacy and efficiency of our body system.