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In biology, depolarization or hypopolarization [1] [2] is a change within a cell, ... The endothelium that lines blood vessels is known as vascular endothelium, which ...
K ir channels close upon depolarization, slowing membrane repolarization and helping maintain a more prolonged cardiac action potential. This type of inward-rectifier channel is distinct from delayed rectifier K + channels , which help repolarize nerve and muscle cells after action potentials ; and potassium leak channels , which provide much ...
The endothelium maintains vascular homeostasis through the release of active vasodilators.Although nitric oxide (NO) is recognized as the primary factor at level of arteries, increased evidence for the role of another endothelium-derived vasodilator known as endothelium-derived hyperpolarizing factor (EDHF) has accumulated in the last years.
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 ...
Cardiovascular physiology is the study of the cardiovascular system, specifically addressing the physiology of the heart ("cardio") and blood vessels ("vascular").. These subjects are sometimes addressed separately, under the names cardiac physiology and circulatory physiology.
This is the depolarization phase. When the membrane potential reaches the threshold potential (around -20 to -50 mV), the cell begins to rapidly depolarise (become more positive). [16] This is mainly due to the flow of Ca 2+ through L-type calcium channels, which are now fully open. During this stage, T-type calcium channels and HCN channels ...
L-type Calcium Channels contain 5 different subunits, the α1(170–240 kDa), α2(150kDa), δ(17-25 kDa), β(50-78 kDa), and γ(32 kDa) subunits. [8] The α2, δ, and β subunits are non-covalently bonded to the α1 subunit and modulate ion trafficking and biophysical properties of the α1 subunit.
Early afterdepolarizations (EADs) occur with abnormal depolarization during phase 2 or phase 3, and are caused by an increase in the frequency of abortive action potentials before normal repolarization is completed. [1]