Part 6: Flesh

Note: For background on this series, please read the Introduction to the 32-Parts Project.

From the collection of anatomical drawings by Bernardino Genga (1620 — 1690), courtesy Wikimedia Commons

Getting to the meat of it, the sixth part of the Meditation on the 32 Parts of the Body is flesh. Flesh is muscle, the most abundant tissue in the body. The body has three kinds of muscle tissue. Cardiac muscle keeps the heart pumping throughout a person’s lifetime. Smooth muscle lines the veins, arteries, intestines, stomach, bladder, and various other organs and vessels. Cardiac and smooth muscle are responsible for moving substances through the body. They contract involuntarily, and we have no direct control over them.

Skeletal muscle gives power to the body, allowing it to move. The contraction of skeletal muscle is voluntary. That is, we can exert conscious control over our flesh, although it may not always seem so. Sometimes the voluntary control over our muscles is overridden by the nervous and endocrine (hormone) systems. Skeletal muscle also helps keep us warm. About 85% of body heat is generated through muscle contraction.

Muscle moves the body through contractions stimulated by the nervous system. When a muscle contracts it applies force to bones, which are linked together in a series of joints. While the nervous system – inspired by our thoughts to move – is stimulating muscles to contract, it also is inhibiting the contraction of other muscles. If all muscles contracted at once and with equal force, we’d be unable to move at all. So with every movement of a normal body, there is complex coordination of muscle contraction and relaxation.

As a person ages, muscle mass and strength diminish, impairing movement. In my own body I notice subtle (and sometimes not so subtle) changes in my ability to do things. Some chores have become more difficult merely because I don’t have the strength I once had to do them.

One of my occupations is that of licensed massage therapist. I work directly on the muscles of others, young and old. I also teach classes in kinesiology – the science of human movement – to students interested in pursuing that career. I’ve had several opportunities to visit a cadaver lab and examine at hand the muscles of the body.

Clinical studies aside, examining a cadaver is a good opportunity to contemplate a body that has lost its life. As we all will.

For background on this series, please read the Introduction to the 32-Parts Project.