Cardiac muscle serves many necessary functions, leading to a specific structure that serves these functions. The structure highlighted is an important histology component of cardiac muscle. What would be the outcome if this structure diffusely failed to function?
AFailure of potassium channels to appropriately open to repolarize the cell
BFailure of propagation of the action potential from the conduction system
CIneffective excitation-contraction coupling due to insufficient calcium ions
DInappropriate formation of cardiac valve leaflets
EOutflow tract obstruction
A 72-year-old man comes to the physician because of a 6-month history of intermittent dull abdominal pain that radiates to the back. He has smoked one pack of cigarettes daily for 50 years. His blood pressure is 145/80 mm Hg. Abdominal examination shows generalized tenderness and a pulsatile mass in the periumbilical region on deep palpation. Further evaluation of the affected blood vessel is most likely to show which of the following?
AObliterative inflammation of the vasa vasorum
BFormation of giant cells in the tunica media
CNecrotizing inflammation of the entire vessel wall
DFragmentation of elastic tissue in the tunica media
EAccumulation of foam cells in the tunica intima
An 80-year-old man is admitted to the hospital after the sudden onset of sub-sternal chest pain and shortness of breath while sitting in a chair. He has hypertension and type 2 diabetes mellitus. He has smoked 1 pack of cigarettes daily for 42 years. Four days after admission, he becomes tachycardic and then loses consciousness; the cardiac monitor shows irregular electrical activity. Cardiac examination shows a new systolic murmur at the apex. Despite appropriate measures, he dies. Microscopic evaluation of the myocardium is most likely to show which of the following?
AWavy myocardial fibers without inflammatory cells
BCoagulative necrosis with dense neutrophilic infiltrate
CLow cellularity with dense, non-contractile scar tissue
DDense granulation tissue with collagenous scar formation
EHyperemic granulation tissue with abundance of macrophages
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