Smart Art: Medicine

Medical Lab Scientist Using Microtiter Plate
Photographic Print
16 in. x 16 in.
Framed | Mounted

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With that in mind, we present to you this....

Overview of the Human Anatomy

The basic building block of the human anatomy is the cell. A tissue is a group of connected cells. Thus, bone tissue is made up of cells and so is organ tissue.

The four basic types of human tissue are:

1. Connective. These form the body's structure. Bone and cartilage are this type of tissue.
2. Epithelial. These tissues line inner and outer body surfaces. Skin is an example, but so is your intestinal lining.
3. Muscle. This type of tissue has the ability to strongly contract, thus enabling movement.
4. Nervous. Nerves are an obvious example. These tissues carry the body's electrical signals.

Tissues are also arranged into organs. An organ consists of two or more types of tissue that work together to accomplish a specific job. The only exception is the skin, which is a single-tissue organ and the body's largest organ. Most organs are part of a system. For example the digestive system.

Organ systems work to maintain "homeostasis," which essentially means they are constantly adjusting to keep certain chemical markers or other "measuring sticks" at specific levels. For example, the respiratory system tries to keep carbon dioxide at a certain level. If the level gets too high, respiration will alter to change it. That's one reason why people yawn or sigh.

Perhaps the most abused system of the body is the endocrine system. Certain foods are known as "endocrine modifiers," and they throw this system completely out of whack. As it tries to adjust, it either cannot move fast enough or it overcompensates such that the system goes into oscillation. Thus, you should not consume these foods. Examples are fruit juices and corn sweeteners.

The iconic image of anatomy is the human skeleton. Barring birth defect or injury, it is the same skeleton for all humans. Contrary to popular opinion, even members of Congress have a backbone. The human skeleton consists of 206 bones, but at birth this number is different (the skull, for example, must knit together after birth). Bones are not the only component of the skeleton. Some parts, such as the nose and ears, consist of cartilage. You also have cartilage in the joints, as every football player with a bad knee can tell you. Ligaments, which are bands of fibrous tissue, hold the bones together.

Bones are very active components of the body, not the dead tissue of Halloween or anatomy class model fame. Bones produce red blood cells and store calcium, among other things. There are three types of specialized cell in bones, and they work together to form the bone matrix. This matrix is continually being dissolved and reconstituted. The entire human skeleton gets replaced over the span of a few years. Unfortunately, new bone follows the pattern of old bone so deformities persist and errors get introduced in this copying process. Bones are so complex that the study of them is a medical specialty.

Bones are joined by, you guessed it, joints. Some joints move, and some do not. The most complex joint is the shoulder, which must do a variety of things in several planes of motion.

The "motors" that move skeletal bones are the muscles. The typical modern human has atrophied muscles, and for the same reasons has weak bones. Many people exercise in an attempt to correct this, but their lack of understanding of the musculo-skeletal system results in their developing muscle imbalances. Knowledgeable body builders (a group that includes top athletes in all sports) have perfect muscular balance surrounding a particular major joint (or set of joints, such as the spine), though they may have preferential muscular development rather than perfect body symmetry. For example, climbers tend to have underdeveloped chests but overdeveloped backs and sprinters tend to have overdeveloped legs and underdeveloped arms. Muscle science is, like the study of bones, amazingly involved and a specialty in its own right.

That's an overview of the human anatomy.