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The lanthanide contraction is the greater-than-expected decrease in atomic radii and ionic radii of the elements in the lanthanide series, from left to right. It is caused by the poor shielding effect of nuclear charge by the 4f electrons along with the expected periodic trend of increasing electronegativity and nuclear charge on moving from left to right.
The lanthanide contraction, i.e. the reduction in size of the Ln 3+ ion from La 3+ (103 pm) to Lu 3+ (86.1 pm), is often explained by the poor shielding of the 5s and 5p electrons by the 4f electrons. [18] Lanthanide oxides: clockwise from top center: praseodymium, cerium, lanthanum, neodymium, samarium and gadolinium.
They conduct cardiac action potentials more quickly and efficiently than any of the other cells in the heart's electrical conduction system. [4] Purkinje fibers allow the heart's conduction system to create synchronized contractions of its ventricles, and are essential for maintaining a consistent heart rhythm. [5]
The bundle of His (BH) [1]: 58 or His bundle (HB) [1]: 232 (/ h ɪ s / "hiss" [2]) is a collection of heart muscle cells specialized for electrical conduction.As part of the electrical conduction system of the heart, it transmits the electrical impulses from the atrioventricular node (located between the atria and the ventricles) to the point of the apex of the fascicular branches via the ...
For example, the muscle tone of the smooth muscle tissue of the tunica media can be adjusted by the renin–angiotensin system. In patients whose endogenous homeostatic regulation is not working well, dozens of pharmaceutical drugs that are also vasoactive can be added. The response of vessels to such vasoactive substances is called ...
In order to maximize efficiency of contractions and cardiac output, the conduction system of the heart has: Substantial atrial to ventricular delay. This will allow the atria to completely empty their contents into the ventricles; simultaneous contraction would cause inefficient filling and backflow.
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.
This is a list of human anatomy mnemonics, categorized and alphabetized.For mnemonics in other medical specialties, see this list of medical mnemonics.Mnemonics serve as a systematic method for remembrance of functionally or systemically related items within regions of larger fields of study, such as those found in the study of specific areas of human anatomy, such as the bones in the hand ...