The first hint of the cellular character of living organisms came from the observation of Robert Hooke, an English physicist, who saw in a piece of cork. It requires veins to transport the blood to the rest of the body, and veins to return the impure blood.
Shapes of Cells
Later, when cells begin to specialize to form a unique organic structure, they can adapt to the availability of space. Its task is, of course, to transport oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs.
Cell Size
The round edge allows it to slide smoothly and evenly squeeze through the long and narrow capillaries.•A nerve cell must communicate all the information collected by the sense organs such as the eye, ear or nose to the brain and direct the given command. of the brain to the muscles. The precise shape and size of a cell is therefore dictated by the way in which the cell can do this most efficiently.
A Visit to a
Chemical Factory
The Manager
This is the nucleolus, which is involved in the production and export of certain materials to the cytoplasm. The proteins that form the building blocks of the organism are manufactured according to the design handed down by the DNA.
The Assembly Line
There are different types of RNA molecules; some carry the message from the DNA to the site of production;. In mycoplasma and bacterial cells they lie free, while in higher cells they are mostly bound to the membrane network known as the endoplasmic reticulum.
The Power 110use
A double layer of lipids and proteins, apparently similar to the nuclear membrane and the outer cell membrane, covers the mitochondria. The outer membrane is fairly elastic, allowing the mitochondria to swell or contract as needed.
The House-Keeper
Not surprisingly, there is a correlation between mitochondrial location and intense cellular activity. Thus, we see that in muscles the mitochondria are close to the muscle fibers which convert chemical energy into a mechanical form.
The Compound Wall
The plant cells and many unicellular organisms have an extra coat that surrounds the cell membrane. This is the cell wall, which consists mainly of cellulose-like substances which are derivatives of sugar compounds.
The Dance of Creation
The Drama of Growth
They become visibly separated as long, thin threads during the next act of the drama, when the cell enters the next phase: prophase. The chromosomes then begin to thicken and shorten, so that each one can not only be seen clearly, but even identified individually. At the same time, the cell membrane around the equator begins to split until two daughter cells are formed, which move apart.
Although the dance of chromosomes, the formation of the spindle, and the formation of daughter cells are visible events, cell division also involves the assimilation of raw material from the outside, with the help of which new building blocks are formed. Because the daughter cells contain the exact complement and number of chromosomes, they are equipped with an identical blueprint of the master.
If each of the fusion partners, sperm and egg, have the full number of chromosomes, the zygote will contain twice the number of chromosomes. This is ensured by two nuclear divisions but only one division of the chromosomes which is the characteristic feature of meiosis. Sperm cells also have 23 chromosomes; half of the sperm cells carrying an X chromosome and half carrying a Y chromosome.
In the first division, prophase is a long and elaborate phase during which homologous pairs fuse together so that during the first anaphase both members of the pair and not the chromatids of the same chromosome move in opposite directions. This increase in mass of a billion times is achieved by the processes of growth and differentiation.
Teams of Workers
The Outer Cover
Sensory stimuli in the skin are triggered by changes in pressure or temperature, tissue damage, etc. Therefore, the skull is built of flat plates and the spine or spine of hollow rings. That's why it comes in two basic types: spongy, which is light and porous, like a spine; and compact, which is dense and strong as in the bones of the legs.
The bones contain almost all the minerals found in the body, such as calcium, phosphorus, copper, cobalt, etc. Therefore, the elbow joint is like a hinge, while that in the shoulder is like a socket.
The Cables
It uses fuel in the form of coal and water to generate energy, which allows it to pull the entire train load. The human body is also like an engine that burns fuel in the form of food, water and air to convert it into energy that enables it to sustain life. They are organized together into systems depending on the exact task they perform during normal engine operation.
The energy created in this way must be transferred to all parts of the body, to every single cell, so that the small 'chemical factory' continues to work efficiently. It has its own control and communication network in the form of the central nervous system.
Burning the Fuel
Therefore, the food mixture does not come out of the nose or enter the windpipe. It is an elaborate food processing factory that turns food into the normal components of the blood. This inflow causes elongation of the muscular wall which is then induced to contract, dumping the contents into the ventricle.
From the left atrium, the oxygen-rich blood passes into the left ventricle through the mitral valve, which closes when the contraction of the ventricle tries to force the blood backward. The rhythm of the heart is maintained by electrical activity generated by the heart cells themselves.
The Purificaiion
The complicated canal system of the stream can easily provide an ideal model for any city water supply. The capillaries further along the route merge to become venules which further unite to become veins. The muscular walls of the arteries absorb this shock and also soften the flow by the time it reaches the different parts of the body.
Valves located at regular intervals along the veins ensure that the flow is in one direction only. When they reach the capillaries bordering a tissue cell in the distant parts of the body, they unload oxygen and are loaded with carbon dioxide in its place.
The Drainage System
The Wast
The gaseous waste product of carbon dioxide is carried away by the red blood cells and transferred to the alveoli in the lungs, where it is exhaled.
The Filter
Thus, protein digestion also creates nitrogen-containing compounds, mainly urea. One of the functions of filtration is to help maintain the essential balance of various salts in the blood. Microscopic droplets of fluid from each of the nephrons pass to be stored in the bladder. The bladder, when full, exerts a pressure on the muscular wall which begins to contract rhythmically.
The rate at which urine is formed varies depending on the concentrations of different substances in the blood and the need to maintain the different balances. Some of the waste is used to form the bitter greenish-yellow digestive juice of bile.
Communication
The Command Headquarters
Seventy percent of the brain is made up of the cerebrum, which consists of two hemispheres. The right hemisphere deals with the left side of the body and vice versa. Consciousness is also due to the cerebrum; it is the constant activity of the brain cells.
The constant, continuous operation of the body's machinery is the result of the smooth functioning of the medulla oblongata. It maintains all essential regulatory mechanisms of the body such as breathing, blood circulation, blood pressure, wakefulness and sleep.
The Signal Corps
No wonder, then, that although it makes up only two percent of the body's weight, it requires twenty percent of the body's oxygen and blood supply. These chemicals can cross the synapse to bind to their respective receptors on the dendrites of the next cell that is now excited. But for the biochemical machine of the body to function smoothly, the reactions must take place slowly and specifically.
Others are released by several other endocrine glands located in different parts of the body. Messages from inside the body are received by receptor neurons attached to various parts.
This wave travels down to the synapse and releases chemicals such as norepinephrine or acetylcholine. It is only because of this doubling of information that reaches the brain's visual cortex that it is able to construct a three-dimensional image. If the eye is the body's camera, the ear is the microphone, which brings in information about the environment by receiving sound waves.
In turn, this activates one of the 30,000 neurons to carry the message to the brain. Death is merely the inevitable degeneration of the particular house it had temporarily inhabited.
Like the ovaries, they remain dormant until the individual reaches the age of puberty. The opening for the sperm, the cervix, increases mucus secretion to facilitate the sperm's entry. The menstrual flow occurs every 28 days or so in accordance with the release of the egg by the ovaries.
During sexual intercourse, it enters the woman's vagina and quickly enters the uterus through the cervix to continue into the fallopian tubes. Arteries carry waste from the fetus to the placenta where it is distributed in the mother's bloodstream.
Eternal Journey
Glossary
Incus: One of three small vibrating bones in the outer ear attached to the tympanic membrane. Jejunum: That part of the small intestine that intervenes between the duodenum and the ileum. Malleus: One of three small vibrating bones in the outer ear attached to the tympanic membrane.
Stapes: One of three small vibrating bones in the outer ear, attached to the lymph membrane. Tricuspid valve: The valve between the right atrium and the right ventricle of the heart.
