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muscle

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Secondary Information

Definition

Muscle is a type of tissue that can contract and relax. This allows muscles to generate force and move bones and other parts of the body. Muscles are made up of long, thin cells that are bundled together. When these cells contract, they shorten and pull on the bones or other parts of the body. This is how muscles move.

Muscles are controlled by the nervous system. When the brain sends a signal to a muscle, it causes the muscle cells to contract. The strength of the contraction depends on the strength of the signal from the brain.

Muscles are also able to store energy. This energy is stored in the form of ATP, which is a molecule that provides cells with energy. When muscles contract, they use ATP to power the contraction.

Muscles are essential for movement. They allow us to walk, run, jump, and perform many other actions. Muscles also help to maintain posture and to keep our organs in place.

How can the word be used?

The athlete used all his muscles to win the race.

muscle

Different forms of the word

Noun: A band of tissue that can contract and relax to produce movement.

Verb: To exert force or strength.

Adjective: Relating to muscle.

Etymology

The word "muscle" comes from the Latin word "musculus," which also means "muscle." The Latin word "musculus" is derived from the Proto-Indo-European root "meu-," which means "to swell.".

The word "muscle" has been used in English since the 14th century. It is a common word that is used in many different contexts.

Question

What are muscles?

AQA Science Exam Question and Answer

Question:

Explain the structure and function of muscles in the human body. Provide examples of different types of muscles and their roles in movement.

Answer:

Muscles are essential components of the human body responsible for various types of movement and maintaining posture. They are composed of muscle fibres that contract and relax to create force and motion.

There are three main types of muscles: skeletal, smooth, and cardiac. Skeletal muscles are attached to bones and enable voluntary movements like walking and lifting. They are under conscious control. Smooth muscles are found in internal organs such as the stomach and blood vessels, and they facilitate involuntary movements like digestion and blood vessel constriction. Cardiac muscles form the heart walls and are responsible for pumping blood; they exhibit rhythmic contractions without conscious control.

Skeletal muscles have a hierarchical structure, with muscle fibres bundled together in fascicles. These fibres contain myofibrils, composed of sarcomeres that contract due to the sliding of actin and myosin filaments. This sliding filament mechanism is crucial for muscle contraction.

For example, when lifting a weight, skeletal muscles contract to generate force. The biceps, a skeletal muscle, contracts to bend the elbow, while the triceps, an antagonist muscle, relaxes. In the digestive system, smooth muscles contract to move food through the digestive tract.