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Light micrograph of a moss's leaf cells at 400X magnification. The following outline is provided as an overview of and topical guide to cell biology: . Cell biology – A branch of biology that includes study of cells regarding their physiological properties, structure, and function; the organelles they contain; interactions with their environment; and their life cycle, division, and death.
Betz cells are not the sole source of direct connections to those neurons because most of the direct corticomotorneuronal cells are medium or small neurons. [3] While Betz cells have one apical dendrite typical of pyramidal neurons, they have more primary dendritic shafts, which can branch out at almost any point from the soma (cell body). [4]
1839: Theodor Schwann [43] and Matthias Jakob Schleiden elucidated the principle that plants and animals are made of cells, concluding that cells are a common unit of structure and development, and thus founding the cell theory. 1855: Rudolf Virchow stated that new cells come from pre-existing cells by cell division (omnis cellula ex cellula).
On 2021, Stephen Quake guessed that the upper limit of the number of human cell types would be around 6000, based on a reasoning that "if biologists had discovered only 5% of cell types in the human body, then the upper limit of cell types to discover is somewhere around 6000 (i.e., 300/0.05)." [10] Other different efforts have used different ...
Date/Time Thumbnail Dimensions User Comment; current: 14:03, 1 February 2007: 462 × 378 (425 KB): Nl74 {{Information| |Description={{en}}a comprensive diagram of a human cell nucleous. {{cs}}schéma buněčného jádra. {{hu}}az emberi sejtmag felépítése |Source=Image:Diagram human cell nucleus.svg |Date= 2007-02-01 (translation) |Author= translate
Many books such as Human Anatomy for Artists: The Elements of Form, are written as a guide to drawing the human body anatomically correctly. [4] Leonardo da Vinci sought to improve his art through a better understanding of human anatomy. In the process he advanced both human anatomy and its representation in art.
The cells of meristematic tissue are similar in structure and have a thin and elastic primary cell wall made of cellulose. They are compactly arranged without inter-cellular spaces between them. Each cell contains a dense cytoplasm and a prominent cell nucleus. The dense protoplasm of meristematic cells contains very few vacuoles.
Every time a basal cell divides, it creates two daughter cells, one is an identical basal cell, and the other is a new somatic cell that undergoes terminal differentiation. These cells gradually get pushed up through the layers of the epidermis by the constant proliferation of more new cells, gradually differentiating and flattening as they rise.