Movements on their own
Smooth muscle and involuntary movement.
After a meal
After a meal, your stomach and intestines keep moving food along. You do not decide to make them move.
What kind of muscle do you think does this work?
What this lesson covers
The idea
Involuntary movements occur without conscious control; smooth muscles, found in organs like the stomach and intestines, have spindle-shaped cells with a single nucleus and no striations, and produce slow, continuous movements.
After a meal
After a meal, your stomach and intestines keep moving food along. You do not decide to make them move.
What kind of muscle do you think does this work?
- A muscle that works without our control
- A muscle that we control by thinking
- A muscle attached to the skeleton
Skeletal or smooth
Tap the muscle that each description fits.
Without our control
Many movements of the body happen automatically, for example the movement of food in the intestine. They are called involuntary movements. Smooth muscles, found in organs like the stomach and intestines, bring them about.
Involuntary movements occur without conscious control. Smooth muscles, found in organs like the stomach and intestines, have spindle-shaped cells with a single nucleus and no striations, and produce slow, continuous movements.
Notes
Involuntary movements need no conscious control. Smooth muscle (stomach, intestines): spindle-shaped, one nucleus, no striations, slow and continuous.
Check yourself
Involuntary movements are those that…
Where are smooth muscles found?
Smooth muscle cells are…
Smooth muscles help with which kind of movement?
- occur without conscious control — correct. Yes!
- we plan and carry out on purpose. Those are voluntary movements, such as running or writing.
- are made only by bones. Bones do not move on their own. Involuntary movements come from muscles working without our control.
- Attached to the skeleton. Skeletal muscles are attached to the skeleton.
- In organs like the stomach and intestines — correct. Yes!
- Only in the heart. Cardiac muscle is the one found only in the heart.
- long and cylindrical with many nuclei. That describes skeletal muscle fibres.
- cylindrical and branched with faint striations. That describes cardiac muscle fibres.
- spindle-shaped with a single nucleus and no striations — correct. Yes!
- Slow, continuous movements like digestion — correct. Yes!
- Voluntary movements like running. Running is a voluntary movement carried out by skeletal muscles.
- Writing and lifting objects. Writing and lifting are voluntary movements carried out by skeletal muscles.