Why do we have a skeleton and how do we move it?

The skeleton give us our shape and keeps our body upright. Without the bony framework, we would probably have looked like a flabby jellyfish on land, because, after all, one-fifth of our body is water. We differentiate our skeleton into the skull, the body, and the limbs. The first two protect us against injuries from outside, and the limb skeleton primarily takes care of our movement. The bones of the skeleton are joined by ligaments. We move with the help of muscles. Muscles become stiff and ache after a vigorous workout.

How many bones does a human being have?

An adult has 206 bones, which together weight about 9 kg. A baby has 350 bones. Many bones in a baby’s skeleton are not full grown, such as those of the skull. Cartilages are present at these points, and turn into bone at a later point. Bones are made up of different materials, and provide strength and nerves, Blood vessels, and bone –building cells. Te bone marrow, which makes the red blood cells, is present inside long bones. The longest bone in our body is the thigh bone.

Which parts of the body does the skeleton protect?

Most of our organs are protected by the skull and the body skeleton. Some of our most sensitive organs lie embedded in the powerful cranial bone of the skull-the brain, the eyes, and the hearing organs. The mouth cavity protects the only movable bone of the skull, the lower jaw. The body skeleton with the ribs fanning out of the backbone protects the area of the chest. Internal organs such as the heart, lung, liver, and spleen are protected behind the rib cage, and the backbone covers the vital spinal cord.

How are the bones joined with one another?

Many of our bones are joined to one another   through joints, which permit different kinds of movements. The ball joints of our hips and shoulders offer the highest freedom of movement. Here, the ball-shaped end of one bone moves inside the bowl-shaped end of the other. Knees and elbows are joined by means of a hinge joint, which permits only the back and forth movement, like the hinge in a door. Our head sits on a condyloid joint, which allows it  to move sideways, front or back, but not rotate. Fluid is present in the joints as a lubricant so that the joints and the bones do not rub against each other.

How do muscle works?

The muscles are connected with bones through rope-like tendons and can only be contracted. Most of the muscles work in pairs so the different types of movements are possible. Such a muscle pair is needed, for instance, to bend the elbow. Which one muscle, the biceps, contracts and bends the arm, the other muscle, the triceps, relaxes. Exactly the reverse happens when the arm is stretched. The signal for muscle contraction or relaxation comes from the brain, which is controlled by us. The musculature of the internal organs works by itself since we cannot control these muscles.

What is muscle stiffness?

Muscle stiffness is a painful result of over strained muscle. It frequently occurs on days when the body suffers very strong physical stress. Physical strain causes micro cracks in the muscle fibers, which slowly get filled with water. As a result of this , the tissue gets stretched, which causes pain, and give rise to inflammation. After a few days of recuperation, the pain usually subsides.

Did you know : the only bone not connected with the rest of the skeleton is the hyoid bone? It lies at the root of the tongue. And the eye muscles move about 100,000 times a day? Most of the movements take place in the night while dreaming.