What Is The Smallest Cell In The Human Body

Table of contents:

What Is The Smallest Cell In The Human Body
What Is The Smallest Cell In The Human Body

Video: What Is The Smallest Cell In The Human Body

Video: Biology L-5 | Smallest and Largest Cell | By - Sonali Ahuja | Science lectures |Only Civil Service 2022, December
Anonim

A cell is an elementary structural unit of any living organism. There are organisms consisting of one cell and multicellular. The latter include a person.

Lymphocytes are the smallest cells
Lymphocytes are the smallest cells

It is impossible to indicate the exact number of cells in the human body: it is not the same for different people and is constantly changing, but on average it is one hundred trillion.

The cells of the human body are not only numerous, but also diverse - there are more than 200 varieties of them. Their genetic set is the same, but some genes work, while others are "silent", this explains the striking differences between cells with the same genome.

Human cells differ from each other in their function, structure, lifespan and size.

Reproductive cell

The smallest cell of the human body is often called the sperm - the male gamete (sex cell). At first glance, its size is quite large - 55 microns, but most of this length falls on the tail - a flagellum that performs only a motor function.

The head is 2.5 µm in height and 3.5 µm in width. It contains a nucleus carrying a haploid (single) chromosome set, and in front of it is an acrosome - a modified lysosome. This organelle contains substances that dissolve the shell of the egg.

A cytoskeleton entwined with mitochondrion, a huge spiral mitochondria, passes through the middle part. The total length of the head and middle part is 9, 5 microns - this is what they mean when they call the sperm the smallest cell.

However, spermatozoa are found only in the body of a sexually mature man, and female gametes - eggs - are the largest human cells, their size reaches 0.5 mm. The smallest "cell of life" in the female body must be sought among the somatic cells.

Somatic cells

The second largest cell in the male body and one of the smallest in the female is a neuron, a structural unit of the nervous system. There are neurons only 3 microns in size. However, there are also large neurons - up to 130 microns, and the average indicator turns out to be not so small - 68 microns, this significantly exceeds the size of the sperm, taking into account the tail.

In addition, even in the smallest neurons, only the bodies - somas - are small. The length of axons - processes that conduct a nerve impulse from the body of a neuron - reaches tens of centimeters. The same situation arises as with the sperm: if we take into account the tail of the male gamete and the axon of the neuron, both cells immediately lose their right to the title of "smallest".

The most likely contenders for this "title" are lymphocytes - colorless blood cells, a type of leukocytes. They range in size from 7 to 10 microns, and they do not have any "additional details" that can be taken into account or not taken into account when measuring.

Popular by topic