Understanding Muscular Systems

by Desiree Lotz August 29, 2014

The Art of Muscles

Understanding muscular systems — a network of about 650 muscles in the human body — enables not only understanding of body movement, but also art. Blood flow and functions connected with bones, organs and the heart are an important part of its mission. And good art also gets the juices flowing!

There is a beauty to the muscular system… or, should we say the beauty of human movement is determined by the artistic functions of its muscles?

“The painter who is familiar with the nature of the sinews, muscles, and tendons, will know very well, in giving movement to a limb, how many and which sinews cause it; and which muscle, by swelling, causes the contraction of that sinew; and which sinews, expanded into the thinnest cartilage, surround and support the said muscle.”

— Leonardo da Vinci

Basic Terms

First, let’s define a few of the system’s related terms, which will help us in understanding muscular systems and their basic structures.

TISSUE: The substance of any organic body or organ that contains cells and materials between the cells. (From Middle English, tissu, old cloth, weave.)
SINEW (a.k.a. TENDON: A tough band of fibrous connective tissue that usually connects muscle to bone, and is capable of withstanding tension (force). (From Sanskrit, sinati, [he] ties)
TENDON: A connective tissue that joins muscles to bones. (Greek, teinein, to stretch.)
MUSCLE: a tissue composed of cells or fibers, the contraction of which produces movement in the body.; also, an organ that contracts to produce a particular movement. (From Latin, musculus, meaning little mouse – resembling its movements)

Bones, of which there are 206 in the human body, compose the skeletal system. Bone is defined as the hard, rigid form of connective tissue constituting most of the skeleton… composed chiefly of calcium salts.

Bone is connective tissue much like tendons, sinew and muscle!

Calcium salts form the dense hard material of teeth and bones. A normal blood calcium level is essential for normal function of the heart, nerves, and muscles; also, blood coagulation. The mineral magnesium helps carry calcium to the cells in a usable form.

The real beauty, however, is in the functioning of muscular systems – its movement.

Body Movement

Proteins (From Greek, proteios, meaning first) are molecules, which, in turn, are particles made of at least two atoms or sub-particles. Made from amino acids — the 13 building blocks the body needs every day, proteins aid the survival of all living things. Healing wounds, fighting infection and building muscle are their main functions. Healthy proteins provide protection from muscular damage of cells by making them resilient and strong. Perhaps more importantly, they also can repair damage.

Most importantly, protein cylinders within muscles allow for contraction and expansion of muscles. Translated, that is body movement. If you’ve ever watched the dexterity of a concert pianist like Oscar Peterson Gill Evans or Chick Corea… or admired the delicate, if difficult to execute, pliets of a virtuoso ballerina… then you know the aesthetic potential the muscular system retains in its arsenal of capabilities.

Breaking down understanding muscular systems into their tiniest particles and sub-particles of atoms, molecules, amino acids and proteins brings us to the notion that in its purest form the human muscular system may be composed of a series of motions rather than solid particles. In other words, statements like “form follows function” and “function monitors structure” might be the truest statements of both bodily structure and movement.

Certain it is that, barring the impulse to move, an arm and/or a leg does not move without a push from some external motivation or intention.

Types of Muscles

There are three distinct types of muscles:

skeletal muscles,
cardiac (heart) muscles, and
smooth (non-lined) muscles.

The skeletal muscle is a bundle of many cells called fibers — long cylinders which, compared to other cells in your body, are quite big: about one to 40 microns long and 10 to 100 microns in diameter. For comparison, a strand of hair is about 100 microns in diameter, a typical cell about 10 microns in diameter.

Muscle fibers contain many cylinders of muscle proteins that enable coordinated contraction.

Cardiac or heart muscle is distinct from skeletal muscles because the fibers are laterally connected to each other and they are not self-controlling. The autonomic nervous system controls heart muscles.

Smooth muscle — so-called because it does not have the microscopic linings of the other two types — is also controlled by the autonomic nervous system, and thought incapable of being moved by conscious thought. This muscle group generally forms the supporting tissue of blood vessels and hollow internal organs, such as the stomach, intestine, and bladder.

Heart beats and lungs, while they can be willingly controlled, are involuntary, but they are not smooth muscles.

Muscle Functions

Muscles have five main functions:

provide strength,
add balance,
establish posture,
enable movement and
provide heat for the body to keep warm.

Muscles are all about action but, at times, they need their rest. Muscle contraction is performed by protein cylinders shortening their overlapping fibers. This process consumes large amounts of the energy source of muscular cells. The release of this energy powers the contraction. But muscles have the ability to regenerate this energy, too.

At rest, body muscles produce their energy by combining oxygen with carbohydrates and fats stored in the body (aerobics). During exercise, energy production varies depending on the fitness of the individual as well as the duration and intensity of the exercise.

At lower activity levels, when exercise continues for a long duration (several minutes or longer), energy is still produced with aerobics. Activity higher in intensity and of less duration utilizes alternative methods.

While aerobic training delivers oxygen quicker and accelerates metabolism faster, anaerobic training produces energy much faster and allows near-maximal intensity exercise. However, anaerobics produces significant amounts of lactic acid which renders high intensity exercise unsustainable for greater than several minutes.

Muscle-Calcium Connection

Calcium is released when a skeletal muscle is stimulated to contract. When the muscle no longer needs to contract, the calcium ions are pumped back into storage. Insufficient calcium supply in storage gives the system no other choice than to rob the bones of calcium that the muscles will not replace. Renewed stock of calcium must come from another source.

The whole process of understanding muscular systems and their coordination among atoms, molecules, amino acids, proteins, muscles and bones is an ongoing ballet of form and function, just like the systems.

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The next installment of the series on the human body systems is the Reproductive System. Visit again and get familiar with your body by reading the rest of the series.

DISCLAIMER: We are not doctors. The information supplied in our articles and blogs is meant for educational purposes only. If you have a body condition or disease that needs attention, we recommend that you see your regular medical or nutritional specialist.

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