The Cells in Your human body are working together. Scientists have discovered that the whole body is composed of cells and of the product of their action. Every part of the body consists of cells quite characteristic in shape and size. we learn much of the anatomy and physiology of the whole system.
General Description of Cells In Our Body.
Some cells are so minute that very high powers of the microscope are required to see them, while others are nearly large enough to be seen with the unaided eye. In shape, there is the greatest variation. There are spherical, oval, and spindle-shaped cells; cells with branches extending in vario j directions, and still other cells with six equal sides. In color, there are the extremes from the black to the colorless, and from the brown to the yellowish green. There exists, therefore, a great difference in the shape, size, and color of cells.
Structure of Different Cells In Human Body.
Living cells consist of a transparent, jelly-like material, called protoplasm. The microscope shows that there are two parts to a cell: the body, or the greater part of the cell; and the nucleus, or tho smaller part in the center. The nucleus is usually spherical or oval, and, with few exceptions, is found in all cells. In rapidly growing cells, two or more nuclei are often found. The nucleus of a cell can be shown very clearly by the use of a carefully prepared solution of carmine. As the microscope shows, the carmine stains each nucleus bright red, but does not affect the body of the cell.
The Life of a Cell.
It is probable that the great majority of cells are. comparatively speaking, short-lived. We must remember that the cells are constantly and rapidly changing. Each movement of the body, each activity of a part, must cause a wear and waste of tissue; and this loss must be replaced by new material within a short time.
There are many ways of showing that the body is ever wasting away. If a drop of saliva placed under the microscope, a vast iiuiuImt of thin cells can be seen. These cells come from the mucous membrane lining the mouth. The motion of the tongue, lips, and cheeks, as in speaking, eating, and drinking, removes vast numbers of these bodies. Then again, the surface of the whole hotly is covered with cells, many layers deep. The outer cells are easily removed by the friction of the clothing, and by the use of the sponge and the towel at the daily bath. In this way immense numbers of cells are being constantly destroyed, while new ones are as rapidly being formed beneath the surface to take their places.
A more familiar example wili illustrate this point. The finger nails are composed of cells so minute that a high power of the microscope is required to see them. Each paring of the nail, therefore, must remove vast numbers of these cells; and yet, how rapidly even this hard structure grows. Thus we learn that the body is ever changing; the old, ”rn-out, and useless material being constantly cast off, am’ ; new as regularly taking its place.
Some cells are much longer lived than others. It is probable that the cells found in such hard tissues as lxme and cartilage undergo comparatively slow changes, while the cells in some of the glands change with great rapidity. In fact, the whole life history of a cell in some of the most active glands may be covered by a few hours.
Growth and Development of Cells.
Cells increase both in size and number. After reaching certain dimensions, however.tli*jr cease to grow. They may then either maintain the size for the remainder of their life, or they may, by i peculiar process of division, become temporarily smaller. This process is called cell division. When a cell is about to divide, its nucleus becomes constricted in the center, assuming a dumb-bell shape. This constriction increases until the nucleus becomes divided into two nuclei. The body of the cell then undergoes the same change in form until it has divided into two cells, with one nucleu* for each cell. A process, or bud, protruding from the body of a cell is still another method of division. Soon this process separates from the original cell, and a nucleus is developed within it
Some Cells have Motion.
The great majority of the cells in the body are locked and cannot alter their shape or position. There an some, however, that not only have the power to change their shape, but also to move from place to place. These movements are known as the “amoeboid movements,” so named from a very minute animal called the amaba
The amoeba is usually regarded as the lowest form of animal life. It is of jelly-like consistence, and averages from to Sj^ of an inch in diameter. It is found in stagnant water, and in water in which there is decaying animal matter. The amadm is an object of intense interest to all physiologist, In Because it represents not only ft single cell but also ft whole individual. It is remarkable for its constant and rapid changes of form, causing it to move about in any direction. As already stated, the amoeba is an animal, the lowest in the scale; yet it moves; it takes nourishment; it reproduces its own kind ; and it dies.
The Main Functions of Cells;And Why Cells Are So Important In Human body
Each cell in the human body can take material brought to it by the blood and change that material into its own structure. To illustrate: the cells of the salivary glands can take digested food from the blood and change it into the tissue of the salivary glands; the cells of muscle can take something from the blood and build from it true muscular tissue; the cells of the kin can take nourishment from the blood and make fro. it the soft covering for the body. Thus, while a person may eat only one kind of tissue-building food, it is possible for this food to be changed into all the various structures of the body.
But the cell can do even more than this; it can take material from the blool and change it into a substance unlike its own. For instance, a cell in the salivary glands can take material brought to it by the blood and change it into saliva ; cells in the glands of the stomach can take material from the blood and change it into gastric juice.
Composition of the Body.
Water fornix a largo part the weight of ilm body, and there ix also considerable fa We all know that some persons have less flex than other but the body always contains fats; even after long-continued illness there is always some fat still remain if Proteid, which we see in one of its forms in the white c the egg, forms a large part of the solid tissues of the body and it is also found in some of the fluids of the body i’here is also some mineral matter in the body, principally lime, soda, and potash; there is also some iron, and then are traces of other minerals.
Effect of Alcohol upon the Cells
As the strength of a chain depends upon the strength of its individual links, so the health of the body depends upon the health and the perfect working condition of its cells. The cells of the body are bathed with blood and consequently are affected by whatever the blood brings to them. The effect of various substances upon cells similar to the cells of the body has been watched through the microscope.
One observer reports that when a living cell was bathed in a liquid containing a meat extract, it expanded, made more lively movement, and appeared to be benefited. When the cell was bathed in an astringent substance, such as tea, it contracted, became nearly or quite motionless and remained so until again bathed in a nutritive substance, when it revived. But if the cell was bathed in alcohol or an alcoholic solution, it contracted, remained motionless, and could not again lie reviewed. It was dead.
The alcohol that reaches the cells of the body after an alcoholic drink is taken is usually too much diluted to kill tho cells, but it can and often does impair their vitality for a longer or shorter time, in proportion to the amount of alcohol that reaches them.