A 68-year-old man with hypertension (BP 165/95 mmHg, HR 108/min, RR 20/min) dies from acute myocardial infarction complications. Autopsy reveals elevated cardiac troponin I (8.2 ng/mL) and anterior wall infarction on gross examination. Histologic sections of viable myocardium away from the infarct border show branched fibers with centrally located nuclei and specialized cell-cell junctions that electrically couple adjacent cells. Coronary atherosclerosis is noted; valvular disease is absent. Which of the following structures is most responsible for that electrical coupling?
- A)Costameres
- B)Hemidesmosomes
- C)Gap junctions within intercalated discsGABARITO
- D)Tight junctions
- E)Desmosomes only
Explicação
Cardiac muscle cells are joined by intercalated discs that contain gap junctions, allowing rapid spread of depolarization from cell to cell. The branched fibers with central nuclei identify cardiac muscle rather than skeletal or smooth muscle. Electrical coupl... Ver explicação completa e trilha adaptativa →