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Permineralization is a process of fossilization of bones and tissues in which mineral deposits form internal casts of organisms. Carried by water, these minerals fill the spaces within organic tissue. Because of the nature of the casts, permineralization is particularly useful in studies of the internal structures of organisms, usually of ...
Tree remains that have undergone petrifaction, as seen in Petrified Forest National Park. In geology, petrifaction or petrification (from Ancient Greek πέτρα (pétra) 'rock, stone') is the process by which organic material becomes a fossil through the replacement of the original material and the filling of the original pore spaces with minerals.
An experiment from Harvey's Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus. Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus (Latin, 'An Anatomical Exercise on the Motion of the Heart and Blood in Living Beings'), commonly called De Motu Cordis, is the best-known work of the physician William Harvey, which was first published in 1628 and established the ...
These trilobites (Lloydolithus) were replaced by pyrite during a specific type of permineralization called pyritization. Permineralization in vertebra from Valgipes bucklandi Diagenesis ( / ˌ d aɪ . ə ˈ dʒ ɛ n ə s ɪ s / ) is the process of physical and chemical changes in sediments first caused by water-rock interactions, microbial ...
After an action potential initiates, the cardiac cell is unable to initiate another action potential for some duration of time (which is slightly shorter than the "true" action potential duration). This period of time is referred to as the refractory period, which is 250ms in duration and helps to protect the heart.
This process occurs on very long timescales. [44] Weathering accounts for approximately 60-90% of solute calcium within the global calcium cycle. [49] Limestone rock, which consists mostly of calcite, is a prime example of a rich source of calcium to the ocean. The source of the majority of inorganic calcium present in the ocean is due to ...
In vertebrates, the circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the body. [ 1 ] [ 2 ] It includes the cardiovascular system , or vascular system , that consists of the heart and blood vessels (from Greek kardia meaning heart , and Latin vascula meaning vessels ).
Cardiac physiology or heart function is the study of healthy, unimpaired function of the heart: involving blood flow; myocardium structure; the electrical conduction system of the heart; the cardiac cycle and cardiac output and how these interact and depend on one another.