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๐ฌ Think about it
You can raise your arm whenever you want.
But your heart beats and your stomach churns without you telling them to.
Which movements can you control, and which happen on their own?
Let us find out.
What is muscular tissue?
- It is the tissue that produces movement .
- Some movements can be controlled (like moving your arm).
- Others cannot be controlled (like your heartbeat or digestion).
| Type | Definition | Example of movement | Muscle involved |
|---|---|---|---|
| Voluntary | Movement under our conscious control | Lifting a bag, walking, writing | Skeletal muscle |
| Involuntary | Movement that happens without our control | Digestion in the stomach; the heart beating | Smooth muscle and cardiac muscle |
What are skeletal muscles?
- Muscles that are attached to the skeleton .
- They are responsible for voluntary movement (movement under our control).
| Feature | What it means |
|---|---|
| Voluntary | Works under our conscious control |
| Long and cylindrical | The fibres are long, tube-like cells |
| Unbranched | The fibres do not split into branches |
| Multinucleate | Each fibre has many nuclei |
| Striated | Has light and dark bands (stripes) |
What are smooth muscles?
- Muscles found in organs like the stomach and intestines (and in blood vessels).
- They are responsible for involuntary movement (not under our control).
| Feature | What it means |
|---|---|
| Involuntary | Works without our control |
| Spindle-shaped | Cells are pointed at both ends |
| Uninucleate | Each cell has a single nucleus |
| Non-striated | Has no stripes or bands |
What are cardiac muscles?
- Muscles found only in the heart .
- They are responsible for involuntary movement (not under our control).
| Feature | What it means |
|---|---|
| Found only in the heart | Present nowhere else in the body |
| Branched | The fibres split and join like a network |
| Usually uninucleate | Each fibre usually has a single nucleus |
| Faintly striated | Has faint stripes |
| Works without tiring | Beats continuously, all life long, without rest |
Comparison between - skeletal, smooth and cardiac muscles
![3.3.3 Can we control movement in - Tissues in Action - [Teachoo] - Concepts](https://cdn.teachoo.com/b3d602ff-7bdb-4e00-820a-6c60113688d3/3.3.3-can-we-control-movement-in-our-body-image-40.webp)
| Feature | Skeletal | Smooth | Cardiac |
|---|---|---|---|
| Control | Voluntary | Involuntary | Involuntary |
| Location | Attached to the skeleton | Stomach, intestines, blood vessels | Only in the heart |
| Shape | Long, cylindrical | Spindle-shaped | Branched, cylindrical |
| Nuclei | Many (multinucleate) | One (uninucleate) | Usually one |
| Striations | Striated | Non-striated | Faintly striated |
Important Points
- Muscular tissue produces movement.
- Skeletal muscle does voluntary movement and is striated.
- Smooth muscle does involuntary movement and lacks striations.
- Cardiac muscle is found only in the heart and never tires.
โ Test Yourself
-
Which muscle carries out voluntary movement?
View Answer
Skeletal muscle. -
Where are smooth muscles found?
View Answer
In organs like the stomach and intestines. -
Which muscle is found only in the heart?
View Answer
Cardiac muscle. -
Which muscles are striated?
View Answer
Skeletal muscle (strongly) and cardiac muscle (faintly).
Important Definitions
- Muscular tissue โ the tissue that produces movement.
- Voluntary movement โ movement under our conscious control, done by skeletal muscle.
- Involuntary movement โ movement without conscious control, done by smooth and cardiac muscle.
