Question

Discuss factors that contribute to the changes in the myocardium and show an image of the changes. (PLEASE TYPE YOUR RESPONSE BECAUSE EVERYBODY'S HANDWRITING IS DIFFERENT AND SOMETIMES HARD TO READ)

Answer 1

age related changes occur are terminal pump failure, interstitial fibrosis, cardiac dilation, arrhythmias and cardiac death.

Various stimuli can initiate this process, which is combined with compensatory attempts of the body to counteract by several pathobiological mechanisms.

factors responsible are stress,

-high blood pressure

-replaced by the fibrocytes

-atherosclerosis

-hypoxia

increase in Type I and Type III collagen turnover occurs, which is paralleled by a volume increase of the extra cellular matrix(ECM). Subsequently, this turnover decreases as ECM volume decreases, which results in a restoration of the collagen network. The biological mechanism underlying these changes in MMP are induced by mechanical stretch of cardiomyocytes

-valvular incompetence

physiological homeostatic balance between MMP( matrixmetalloproteinase ) and TIMP (tissue inhibitors of matrix metalloproteinases) , thereby facilitating partial geometrical reshaping of the heart

- inflammatory factors:-

the leucocytes, platelets, tissue macrophages and endothelial cells synthesize and secrete inflammatory cytokines such as tumor necrosis factor (TNF) α, interleukin (IL)-1β and IL-6, as well as chemokines.

increased plasma/serum levels of inflammatory mediators are associated with deterioration of functional cardiac performance reflected by diminished left ventricular ejection fraction (LVEF).

The release of inflammatory mediators from the failing myocardium is not necessarily related to necrotic and/or apoptotic cell death of cardiomyocytes.

Activation of NF-κB, a major inflammatory mediator in the failing myocardium, has antiapoptotic effects. Mechanical ventricular overload and shear stress, hypoxia, ischemia and oxidized low density lipoprotein cholesterol have been shown to be potent inducers of inflammatory factors from different cell types including cardiomyocytes .