The cell retains a dual existence as a distinct entity and a building block in the construction of organisms. Theodor Schwann was born at Neuss near Düsseldorf on Dec. 7, 1810. Schwann's thesis involved a careful study of the necessity for oxygen during the embryonic development of the chicken. He was also able to identify important scientific questions and design experiments to systematically test them. The cell theory describes the basic properties of all cells. ...The CELL THEORY, or cell doctrine, states that all organisms are composed of similar units of organization, called cells.The concept was formally articulated in 1839 by Schleiden & Schwann and has remained as the foundation of modern biology. [15]:122 [8]:643[6][7], In 1829 Schwann enrolled at the University of Bonn in the premedical curriculum. [27] At the beginning of 1836, Schwann began to study digestive processes. He spent considerable time perfecting experimental techniques and instruments for use in experiments. [12]:60 He identified the question that he wanted to answer and communicated the importance of his findings effectively to others. [3] Schwann's view furthered a conceptualization of living things in terms of the biological reactions of organic chemistry, while Liebig sought to reduce biological reactions to purely inorganic chemistry. Recuperado en 12 de junio de Semantic Scholar: semanticscholar.org; Mateos, P. One exception was a paper in 1844 that reported on a series of experiments on dogs and established the importance of bile in digestion. He speculated on the possible structural and functional significance of the tubes and fibrils. First he controlled the temperature of fluid from fermenting beer in a closed vessel in the presence of oxygen. [5], Theodor Schwann was born in Neuss on 7 December 1810 to Leonard Schwann and Elisabeth Rottels. Theodor Schwann, (born December 7, 1810, Neuss, Prussia [Germany]—died January 11, 1882, Cologne, Germany), German physiologist who founded modern histology by defining the cell as the basic unit of animal structure. In Cologne his religious instructor Wilhelm Smets [de], a priest and novelist, emphasized the individuality of the human soul and the importance of free will. German physiologist who served as an assistant to Johannes Müller. [13][9]:85–86 However, other authors regard this as misrepresenting his thinking, and reject the idea that Schwann went through an existential crisis or a mystical phase. He also discovered pepsin, the first digestive enzyme prepared from animal tissue, and experimented to disprove spontaneous generation. Next, Schwann tested the effects of purified air and unpurified air. [22][6], His observation that the single-celled ovum eventually becomes a complete organism, established one of the basic principles of embryology. [18][6][3] Schwann coined its name from the Greek word πέψις pepsis, meaning "digestion" (from πέπτειν peptein "to digest"). In 1839, he extended Schleiden's cell theory to animals, stating that all living things are composed of cells. [10]:387 It was translated into English as Elements of Physiology in 1837–1843 and became the leading physiology textbook of the 1800s. He demonstrated that fermentation was not an inorganic chemical process like sugar oxidation. Schleiden and Schwann are jointly credited with having originated the cell theory. [16], When viewed in the context of his unpublished writings and laboratory notes, Schwann's research can be seen as "a coherent and systematic research programmme" in which biological processes are described in terms of material objects or "agents", and the causal dependencies between the forces that they exert, and their measurable effects. Despite the limitations of his now-ancient lenses, van Leeuwenhoek observed the movements of protista (a type of single-celled organism) and sperm, which he collectively termed “animalcules. [3] [3] His most significant contribution to biology is considered to be the extension of cell theory to animals. At the beginning of 1836, Schwann began to study digestive processes. He concluded that sugar was converted to alcohol as part of an organic biological process based on the action of a living substance, the yeast. At Leuven Schwann observed the formation of yeast spores and concluded that the fermentation of sugar and starch was the result of life processes. His co-worker Jakob Henle spoke of him as having an "inborn drive" to experiment. By 1836, Schwann had carried out numerous experiments on alcohol fermentation. [3], Schwann's theory and observations created a foundation for modern histology. That same year his seminal work, Microscopical Researches into the Accordance in the Structure and Growth of Animals and Plants, was published. In 1848 Schwann accepted a professorship at the University of Liège, where he stayed for the remainder of his career. In 1839 Schwann took an appointment as professor of anatomy at the Catholic University of Leuven (Louvain) in Belgium. He developed and described an experimental method to calculate the contraction force of the muscle, by controlling and measuring the other variables involved. [6] Leonard Schwann was a goldsmith and later a printer. He conceptualized digestion as the action of a physiological agent, which, though not immediately visible or measurable, could be characterized experimentally as a "peculiar specific substance".
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