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Cardiac muscle Cardiac sarcomere structure . Cardiac muscle tissue or myocardium forms the bulk of the heart. The heart wall is a three-layered structure with a thick layer of myocardium sandwiched between the inner endocardium and the outer epicardium (also known as the visceral pericardium).
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.
Several species of Kalanchoe are economically important for causing cardiotoxic effects in sheep and cattle, and diseases affecting the nervous system and muscles known as krimpsiekte ("shrinking disease") or as cotyledonosis. [10] Kalanchoe pinnata may have similar chemical components, bufadienolide alkaloids. [11]
The binding of the myosin head to actin is known as a cross-bridge. A molecule, called adenosine triphosphate (ATP) which is produced by an intracellular structure called a mitochondrion, is then used, as a source of energy, to help move the myosin head, carrying the actin. As a result, the actin slides across the myosin filament shortening the ...
A pistil typically consists of an expanded basal portion called an ovary, an elongated section called a style and an apical structure called a stigma that receives pollen. The ovary (from Latin ovum , meaning egg) is the enlarged basal portion which contains placentas , ridges of tissue bearing one or more ovules (integumented megasporangia ).
The Purkinje fibers are further specialized to rapidly conduct impulses (having numerous fast voltage-gated sodium channels and mitochondria, and fewer myofibrils, than the surrounding muscle tissue). Purkinje fibers take up stain differently from the surrounding muscle cells because of having relatively fewer myofibrils than other cardiac cells.
The papillary muscles are muscles located in the ventricles of the heart. They attach to the cusps of the atrioventricular valves (also known as the mitral and tricuspid valves) via the chordae tendineae and contract to prevent inversion or prolapse of these valves on systole (or ventricular contraction). [1]
The anther and pistil were shorter in the rmd-1 mutants than the wild-type. This experiment showed that RMD is critical for pollen development. Wild-type rice plants have increased germination rates while rmd-1 mutants have decreased germination rates. This was seen when both were germinated in a liquid germination medium.