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Bachmann’s bundle

In the heart’s conduction system, Bachmann’s bundle, or the interatrial tract, is a branch of the anterior internodal tract that resides on the inner wall of the left atrium. It is a broad band of cardiac muscle that passes from the right atrium, between the superior vena cava and the ascending aorta. Bachmann’s bundle is, during normal sinus rhythm, the preferential path for electrical activation of the left atrium. It is therefore considered to be part of the “atrial conduction system” of the heart. (wikipedia.org) Named after Jean George...

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Bacillus

/bəˈsiləs/ Noun, pl. bacilli 1. A taxonomic genus within the family Bacillaceae — the rod-shaped bacteria. (wiktionary.org) 2. Bacillus is a genus of Gram-positive, rod-shaped bacteria and a member of the phylum Firmicutes. Bacillus species can be obligate aerobes or facultative anaerobes, and test positive for the enzyme catalase. Ubiquitous in nature, Bacillus includes both free-living and pathogenic species. Under stressful environmental conditions, the cells produce oval endospores that can stay dormant for extended periods. These characteristics originally defined the genus, but not all such species are closely related, and many have been moved to other genera. (wikipedia.org) 3. Aerobic rod-shaped spore-producing bacterium; often occurring in chainlike formations; found primarily in soil. (wordnetweb.princeton.edu) 4. A disease-causing bacterium. (Google Dictionary)   *A note on its word format: The word bacillus (plural bacilli) may be used to describe any rod-shaped bacterium, and such bacilli are found in many different taxonomic groups of bacteria. However, the name Bacillus, capitalized and italicized, refers to a specific genus of bacteria. The name Bacilli, capitalized but not italicized, can also refer to a more specific taxonomic class of bacteria that includes two orders, one of which contains the genus Bacillus. Bacilli are usually solitary, but can combine to form diplobacilli, streptobacilli, and...

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Backbone

/ˈbakˌbōn/ Noun 1. The series of vertebrae, separated by disks, that encloses and protects the spinal cord, and runs down the middle of the back in vertebrate animals. (wiktionary.org) 2. (Science: anatomy) The spinal column, found in vertebrate animals, which runs along the dorsal side and contains the central nerve cord (spinal cord). (biology-online.org) 3. The main structural feature of a polymer (chain-like) molecule from which many side chains branch off. The series of vertebrae forming the axis of the skeleton and protecting the spinal cord. (biology-online.org) 4. A bone structure found in vertebrates where series of vertebrae are positioned in a column with the primary function of protecting the spinal cord and maintaining structure of the organism. (biology-online.org) Syn: spine, spinal column, vertebral...

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