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The Human Body: Skeletal and Muscular System - Types of muscles (Voluntary and Involuntary)

Grade 5ICSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Muscles are soft tissues attached to bones that allow the body to move by contracting and relaxing.

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Voluntary Muscles: These are muscles under our conscious control. Examples include muscles in our arms and legs. They are also known as skeletal muscles because they are attached to the skeletonskeleton.

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Involuntary Muscles: These muscles work automatically without our conscious thought. They control internal organs like the stomach and intestines. They are often called smooth muscles.

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Cardiac Muscles: A special type of involuntary muscle found only in the heart. They work continuously throughout life to pump blood throughout the body without getting tired.

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Muscular Movement: Muscles always work in pairs. When one muscle in the pair contracts (shortens), the other relaxes (lengthens) to pull the bone. Muscles can only pull; they cannot push.

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Muscle cells require energy to function, which is produced through the process of respiration: C6H12O6+6O2→6CO2+6H2O+EnergyC_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{Energy}.

📐Formulae

Muscle Action=Contraction+Relaxation\text{Muscle Action} = \text{Contraction} + \text{Relaxation}

Movement of Bone=Pulling Force of Muscle\text{Movement of Bone} = \text{Pulling Force of Muscle}

C6H12O6+6O2→6CO2+6H2O+EnergyC_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{Energy}

💡Examples

Problem 1:

Identify the type of muscle involved when you kick a football.

Solution:

Voluntary Muscle (Skeletal Muscle).

Explanation:

Kicking is a conscious action controlled by our will, using the muscles attached to the leg bones.

Problem 2:

Which muscle type is responsible for the movement of food through the digestive tract?

Solution:

Involuntary Muscle (Smooth Muscle).

Explanation:

The movement of food (peristalsis) happens automatically without us having to think about it.

Problem 3:

Explain the pair-work of the Biceps and Triceps when bending the arm.

Solution:

Biceps contract and Triceps relax.

Explanation:

To bend the elbow, the BicepsBiceps (front muscle) contracts to pull the forearm up, while the TricepsTriceps (back muscle) relaxes to allow the movement.