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The endothelium that lines blood vessels is known as vascular endothelium, which is subject to and must withstand the forces of blood flow and blood pressure from the cardiovascular system. To withstand these cardiovascular forces, endothelial cells must simultaneously have a structure capable of withstanding the forces of circulation while ...
The myogenic mechanism is how arteries and arterioles react to an increase or decrease of blood pressure to keep the blood flow constant within the blood vessel.Myogenic response refers to a contraction initiated by the myocyte itself instead of an outside occurrence or stimulus such as nerve innervation.
Numerous experimental studies have established that cortical spreading depolarization, the biological substrate for migraine aura, can discharge trigeminovascular afferents as a cause of head pain and by extension unilateral headache overlying the dysfunctional hemisphere in migraineurs with aura. [12]
The P wave is a summation wave generated by the depolarization front as it transits the atria. Normally the right atrium depolarizes slightly earlier than left atrium since the depolarization wave originates in the sinoatrial node , in the high right atrium and then travels to and through the left atrium.
Schematic representation of normal ECG. In electrocardiography, the ST segment connects the QRS complex and the T wave and has a duration of 0.005 to 0.150 sec (5 to 150 ms). ...
The classical explanation of HPV involves inhibition of hypoxia-sensitive voltage-gated potassium channels in pulmonary artery smooth muscle cells leading to depolarization. [ 3 ] [ 4 ] This depolarization activates voltage-dependent calcium channels , which increases intracellular calcium and activates smooth muscle contractile machinery which ...
A former Tennessee teacher who got pregnant after raping a 12-year-old boy pleaded guilty and has been sentenced to 25 years in prison with no parole. On Dec. 20, Alissa McCommon, 39, of Covington ...
HCN4 is the main isoform expressed in the sinoatrial node, but low levels of HCN1 and HCN2 have also been reported.The current through HCN channels, called the pacemaker current (I f), plays a key role in the generation and modulation of cardiac rhythmicity, [13] as they are responsible for the spontaneous depolarization in pacemaker action potentials in the heart.