6. Describe the mechanical events of the cardiac cycle (as in Figure 14.18a), including isovolumic ventricular contraction and isovolumic ventricular relaxation (pressure- volume curve of left ventricle, Figure 14.18b). What causes valves to open and close during a cardiac cycle?

5. Describe the conductions of electrical signals through the heart. answer this question with a narrative of the structures involved in initiating and coordinating the contraction of the heart. You need to include the function of each structure. Mention  pacemaker cells, the sinoatrial node, atrioventricular node, internodal pathway, bundle of His, bundle branches, Purkinje fibers, first degree block, second degree block, and third degree block.

Match the phases of the cardiac cycle given below with the correct corresponding number in the fhigure below. 0.2 04 0.6 0.8 120 100 80+ Pressure changes 60+ 40+ 20+ Left ventricie 120 80 Volume changes 40 V[ Choose ) Isovolumetric contraction 3 Ventricular ejection [ Choose ]

Antiarrhythmic drugs are used to correct an irregular heartbeat. Give 2 examples each of class 1-1V drugs that act at positions 0-4 of the myocardial action potential sequence. Do not give brand names, use generic names.