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The conduction system consists of specialized heart muscle cells, situated within the myocardium. [3] There is a skeleton of fibrous tissue that surrounds the conduction system which can be seen on an ECG. Dysfunction of the conduction system can cause irregular heart rhythms including rhythms that are too fast or too slow.
The underlying cause of the Bowditch effect is an increase in the calcium concentration in the sarcoplasmic reticulum of cardiac muscle cells, and its increased release into sarcoplasm. [ 3 ] One of the explanations for an increase in the intracellular calcium concentration is the inability of the Na + /K + -ATPase to keep up with influx of ...
Valvular heart disease may cause breathlessness, blackouts, or chest pain, but may be asymptomatic and only detected on a routine examination by hearing abnormal heart sounds or a heart murmur. In the developed world, valvular heart disease is most commonly caused by degeneration secondary to old age, but may also be caused by infection of the ...
Cardiac arrhythmias can cause heart block, in which the contractions lose their rhythm. In humans, and sometimes in other animals, a mechanical device called an artificial pacemaker (or simply "pacemaker") may be used after damage to the body's intrinsic conduction system to produce these impulses synthetically.
When the heart contracts during systole, the contraction compresses the coronary arteries, which prevents perfusion. Therefore, it is only when the heart relaxes, during diastole , that the coronary vessels open up and allow for perfusion; thus CPP is highest during diastole, unlike most other arteries, which experience higher perfusion ...
This is an incomplete list, which may never be able to satisfy certain standards for completion.. There are many conditions of or affecting the human circulatory system — the biological system that includes the pumping and channeling of blood to and from the body and lungs with heart, blood and blood vessels.
The cardiac cycle is the performance of the human heart from the beginning of one heartbeat to the beginning of the next. It consists of two periods: one during which the heart muscle relaxes and refills with blood, called diastole, following a period of robust contraction and pumping of blood, dubbed systole. After emptying, the heart ...
The jugular venous pressure (JVP, sometimes referred to as jugular venous pulse) is the indirectly observed pressure over the venous system via visualization of the internal jugular vein. It can be useful in the differentiation of different forms of heart and lung disease. Classically three upward deflections and two downward deflections have ...