The muscles that are under our control called voluntary muscles.
The muscles that are not under our control called involuntary muscles.

Voluntary Muscles

Voluntary muscles, also known as skeletal muscles, are muscles that we can consciously control. They are attached to our bones and play a crucial role in our body movements. Here are some key points about voluntary muscles:

1. Definition: Voluntary muscles are muscles that we can control voluntarily. They are responsible for our intentional movements such as walking, running, and lifting objects.

2. Structure: Voluntary muscles are made up of long, cylindrical cells called muscle fibers. These fibers are bundled together and wrapped in connective tissue to form a muscle.

3. Appearance: Voluntary muscles have a striped or striated appearance, which is why they are also called striated muscles. This striped appearance is due to the arrangement of proteins within the muscle fibers.

4. Contraction: Voluntary muscles contract when they receive signals from our nervous system. These contractions are usually under our conscious control, meaning we can decide when to contract or relax our muscles.

5. Function: Voluntary muscles allow us to perform various movements and activities. They work in pairs or groups to create opposing movements. For example, when we bend our arm, the biceps muscle contracts while the triceps muscle relaxes.

Involuntary Muscles

Involuntary muscles, also known as smooth muscles, are muscles that we cannot consciously control. They are found in various organs and tissues throughout our body. Here are some key points about involuntary muscles:

1. Definition: Involuntary muscles are muscles that work automatically without our conscious control. We cannot directly control their movements.

2. Structure: Involuntary muscles are made up of spindle-shaped cells. Unlike voluntary muscles, they do not have a striped appearance and are smooth in texture, hence the name smooth muscles.

3. Contraction: Involuntary muscles contract involuntarily in response to different stimuli. These contractions are controlled by our autonomic nervous system, which regulates our body's internal functions.

4. Function: Involuntary muscles are found in organs such as the stomach, intestines, blood vessels, and bladder. They play a vital role in various bodily functions such as digestion, blood circulation, and urination.

5. Regulation: The contractions of involuntary muscles are regulated by hormones, neurotransmitters, and other chemical signals in our body. They respond to external stimuli and internal cues to maintain the proper functioning of our organs.

Conclusion

In summary, voluntary muscles are under our conscious control and are responsible for intentional movements, while involuntary muscles work automatically and are involved in the functioning of our internal organs. Both types of muscles are essential for our overall body movements and physiological processes.