Medical research

New method visualizes groups of neurons as they compute

Using a fluorescent probe that lights up when brain cells are electrically active, MIT and Boston University researchers have shown that they can image the activity of many neurons at once, in the brains of mice.

Neuroscience

The brain may actively forget during dream sleep

Rapid eye movement, or REM, sleep is a fascinating period when most of our dreams are made. Now, in a study of mice, a team of Japanese and U.S. researchers show that it may also be a time when the brain actively forgets. ...

Neuroscience

Novel technique helps explain why bright light keeps us awake

In recent decades, scientists have learned a great deal about how different neurons connect and send signals to each other. But it's been difficult to trace the activity of individual nerve fibers known as axons, some of ...

Oncology & Cancer

Drug shows promise as immune therapy for cancer

A therapy developed by Yale researchers stimulates immune cells to shrink or kill tumors in mice, according to a new study published in the Journal of Experimental Medicine. The therapy is effective alone or in combination ...

page 1 from 23

Cell (biology)

The cell is the structural and functional unit of all known living organisms. It is the smallest unit of an organism that is classified as living, and is often called the building block of life. Some organisms, such as most bacteria, are unicellular (consist of a single cell). Other organisms, such as humans, are multicellular. (Humans have an estimated 100 trillion or 1014 cells; a typical cell size is 10 µm; a typical cell mass is 1 nanogram.) The largest known cell is an unfertilized ostrich egg cell.

In 1835 before the final cell theory was developed, a Czech Jan Evangelista Purkyně observed small "granules" while looking at the plant tissue through a microscope. The cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells. All cells come from preexisting cells. Vital functions of an organism occur within cells, and all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells.

The word cell comes from the Latin cellula, meaning, a small room. The descriptive name for the smallest living biological structure was chosen by Robert Hooke in a book he published in 1665 when he compared the cork cells he saw through his microscope to the small rooms monks lived in.

This text uses material from Wikipedia, licensed under CC BY-SA