Muscle: Definition, Function, and Examples

Table of Contents

Muscle Definition

A muscle is a group of muscle tissue that contracts to create strength. A muscle consists of somatic cell fibres surrounded by protective tissue, which are grouped together by many other fibres, all of which are surrounded by thick protective tissue.

A muscle uses ATP to contract and protect itself. shorten, which exerts a force on the objects to which it is attached. There are different types of muscles that act on different parts of the body.

Structure of Muscle

A muscle is made up of many muscle tissues linked together and surrounded by epimysium, a hard connective tissue similar to cartilage. The epimysium surrounds bundles of nerve cells that form long fibres, called fascicles.

These bundles are encapsulated by their protective layer, the perimysium, which allows nerves and blood to flow to individual fibres. Each fibre is then covered in an endomysium, another protective layer.

A muscle is arranged during a basic pattern of fibres in bundles separated by protective layers. These layers and bundles allow distinct parts of a muscle to contract differently. The protective layer surrounding each bundle allows different bundles to slip over one another as they contract.

The epimysium connects to the tendons, which attach to the periosteal connective tissue surrounding the bones. Being anchored to two bones allows skeletal movement as the muscle contracts.

A different sort of muscle surrounds many organs, and therefore the epimysium connects with other connective tissues to supply forces on the organs, controlling everything from circulation to food processing.

Muscle Function

Whether it’s the largest muscle in your body or the small muscle controlling the movement of your eye, each muscle functions in an exceedingly similar manner. a signal is distributed from the brain on a bundle of nerves.

The electronic and chemical message is passed quickly from somatic cell to nerve cell and at last arrives at the motor finish plate. This interface between the muscle and nerve cells releases a chemical signal, acetylcholine, that tells the muscle cell to contract.

This message is distributed to all or any the cells within the fibre connected to the nerve. This signal causes the globulin proteins to grab onto the simple protein filaments around them.

These are the purple proteins within the image below. globulin uses ATP as an energy supply to crawl on the inexperienced filament, actin. As you will see , the varied tiny heads of the myosin fibres crawl along the actin filaments effectively shortens the length of each muscle fibre.

The cells, that are connected end-to-end during a long fibres, contract at a similar time and shorten the full fibre. once a sign is distributed to a whole muscle or cluster of muscles, the ensuing contraction ends up in movement or force being applied.

A muscle are often utilized in many various ways throughout the body. a precise muscle would possibly contract seldom with plenty of force, whereas a special muscle can contract regularly with nominal force. Animals have developed an embarrassment of uses for the forces a muscle will create.

Muscles have evolved for flying, swimming, and running. they need conjointly evolved to be pumps used in the circulatory and organic process systems. the centre could be a specialised muscle, which is uses solely for pumping blood throughout the body. These differing types of muscle will be mentioned below.

Types of Muscle

i. Skeletal Muscle

When you consider a muscle, the general public usually think of a skeletal muscle. The biceps, triceps, and quad are all common names for muscles that body builders tend to specialise in.

In fact, these general muscles are typically composed of the many little muscles that attach to totally different places to relinquish a joint its full vary of motion. striated muscle may be a striated muscle.

This suggests that every vegetative cell has striations, or linear marks, which may be seen once this muscle is put out a microscope. The striations correspond to the sarcomeres present in striated muscles, that are extremely organized bundles of muscle cells which may contract quickly in concert.

Striated muscle is controlled via the corporeal systema nervosum, additionally called the voluntary nervous system. purpose your finger to the ceiling. this can be your somatic nervous system in action, dominant your skeletal muscles.

ii. Cardiac Muscle

The heart muscle, although similar in some ways to skeletal muscle, is connected to the autonomic nervous system, which controls vital organs such as the heart and lungs and allows us to avoid having to concentrate on pumping our heart every time it beats.

Although the autonomic nervous system has some control over consciousness, it is always activated when we are unconscious. For example, you can hold your breath if you want, but don’t have to remember to breathe all the time.

The heart muscle surrounds the chambers of the heart and is used to pump blood around the body. The heart muscle is similar to the skeletal muscle in that it is striped. In contrast to skeletal muscle, the fibres of the heart muscle are arranged in a branched pattern rather than a linear pattern.

Both the skeletal muscle and the heart muscle need to contract quickly and frequently in order for stretch marks to be seen.

iii. Smooth Muscle

In contrast to the skeletal and heart muscles, the smooth muscles are not striated because the individual muscle cells in the sarcomeres are not perfectly aligned, but rather move along the fibres, which means that the smooth muscles can contract longer, although there is a slower contraction.

Look at the muscle that contracts the bladder sphincter. This muscle may need to stay closed for hours and only relax for a minute when you go to the bathroom. Many other smooth muscles work in the same way.

Like the heart muscle, smooth muscles are primarily controlled by the autonomic nervous system. The many muscles that line your digestive tube work along to maneuver food through the biological process system. swish muscle is found virtually every place in your body and helps with everything from circulation to digestion.

Muscle Citations
  • The determinants of skeletal muscle force and power: their adaptability with changes in activity pattern. J Biomech . 1991;24 Suppl 1:111-22.
  • Cellular mechanisms of muscle fatigue. Physiol Rev . 1994 Jan;74(1):49-94.
  • Iliopsoas the Hidden Muscle: Anatomy, Diagnosis, and Treatment. Curr Sports Med Rep . 2020 Jun;19(6):235-243.
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