What is known about the human body? How many cells are there in an adult? How do they grow and develop, what are they for? Scientists all over the world are trying to solve these puzzles.
What is a cell?
Scientists study the organisms of plants, animals, people. A cell is the smallest part of any organism. In the human body there are a lot of them, more than 100 trillion. The exact number is unknown. How many cells in the human body die every day? Quantity depends on destination. So, for example, in the intestinal epithelium - 70 billion per day, in the blood - 2 billion, and the cells of the nervous system do not recover after dying.
For the first time, Robert Hook learned about cells in 1665 . He realized that the older the person, the more of these structural elements in his body. It is impossible to calculate exactly how many cells in the human body , because they die and are born every minute.
Structure and function
You can’t say how many cells there are in the human body, but scientists know for sure that they have a complex structure.
Most consists of:
- nucleus, it is called the heart of the cell;
- cytoplasm;
- nucleolus;
- mitochondria;
- core shells;
- endoplasmic reticular formation;
- ribosomes;
- lysosomes;
- pits and pores;
- the cell membrane, which ensures integrity, regulates intracellular balance.
Functions are related to the synthesis of substances. Glandular cells produce hormones or enzymes. The mammary glands produce milk, the pancreas - insulin. Some do not synthesize anything, such as muscle cells.
Regardless of how many cells are in the human body, they cannot survive without it. Cells, as elements of a mosaic, make up a single organism.
Blood cells
What is the fluid that flows through the veins of people? It contains plasma and cellular elements:
- red blood cells - red blood cells;
- platelets;
- white blood bodies - white blood cells.
The density and color of blood depends on their content. It carries out the transfer of chemicals throughout the body. An adult has about 50 billion blood cells. This is approximately 5.5 liters.
Pigment cells
Melanocytes in the human body are responsible for the color of the skin, hair, eyes and some internal organs. Such cells contain pigments in the cytoplasm that determine their effect. Melanocytes also perform a protective function against ultraviolet rays, are responsible for tanning. The cells are woody in appearance.
Nervous system cells
This is one of those that do not recover after dying. Their scientific name is neurons. Their task is to process and transmit information using the electrical impulses they produce. Neurons are divided into several types:
- sensory (responsible for the reaction to light, sound);
- motor;
- interneurons.
The composition includes the cell body , dendrite, axon. In their structure, they are also divided into several groups. The human nervous system contains about 10 billion neurons. About 10 thousand die annually and are no longer restored. The older the person, the fewer they remain.
Germ cells
How many cells in the human body are responsible for reproduction? There are two types of them, they are divided into male - sperm - and female - egg cells. The male reproductive cell is much larger in size than the female, as it contains a larger amount of cytoplasm. They were first discovered in 1677, and the terms themselves appeared at the beginning of the 19th century.
Despite the fact that it is impossible to say exactly how many cells are in the human body, scientists have studied almost all their types. Their participation is directly related to the existence of all life on planet Earth. Scientists are trying to learn how to grow human cells on their own in research laboratories. Perhaps they will succeed.