Atria

... lead to parasympathetic stimulation like lead to decrease heart rate but have nothing to do with contractility as no innervation to muscles of atria and ventricles There are other factors which contribute to heart rate regulation like direct action of Epinephrine and NorEpinephrine also there ...

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... stimulation like (rest state) lead to decrease heart rate but have nothing to do with contractility as no innervation to muscles of atria and ventricles there are other factors which contribute to heart rate regulation like direct action of Epinephrine and NorEpinephrine (Adrenaline&NorAdrenaline),also ...

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... system evolved before the septum evolved in the heart separating it. In the case of the frog, everything from the lung just gets dumped into the atria.

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no auricles are not the same as the atria. --> the auricles are part of the atria and these parts of the atria are called auricles, because they look like the 'ears' of the heart.

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When I first learned this many years ago, what we now call "atria" were called "auricles." Somewhere along the way (and this happens a LOT with anatomical terms), the Powers-That-Be tweaked the definitions. The atria are now the actual ...

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