Answer: Activating soluble guanylyl cyclase in VSM cells, increasing cGMP, which activates PKG, leading to smooth muscle relaxation.
- A Directly binding to myosin heads to physically prevent cross-bridge cycling altogether in typical laboratory settings
- B Activating soluble guanylyl cyclase in VSM cells, increasing cGMP, which activates PKG, leading to smooth muscle relaxation
- C Directly blocking voltage-gated calcium channels on the vascular smooth muscle cell membrane under usual circumstances
- D Competitively blocking angiotensin II receptors located on vascular smooth muscle cell surfaces according to most researchers
Correct answer: B. Activating soluble guanylyl cyclase in VSM cells, increasing cGMP, which activates PKG, leading to smooth muscle relaxation
Explanation: NO from endothelial cells diffuses into vascular smooth muscle (VSM). Activates soluble guanylyl cyclase → cGMP rises → PKG activated → MLCK inhibited + K+ channels opened → smooth muscle relaxes → vasodilation.
A single ECG cycle: the P wave marks atrial depolarisation (contraction signal), the large QRS complex marks ventricular depolarisation, and the T wave marks ventricular repolarisation (recovery) before the next cycle begins.
Concept context
Blood, lymph, the heart, the cardiac cycle, blood pressure, and ECG. High NEET weightage.