For each defense mechanism, click to specify whether the defense mechanism is part of the first, second, or third line of defense.

Rationale:

A. Chronic stress triggers the hypothalamic-pituitary-adrenal (HPA) axis, resulting in increased secretion of cortisol, a glucocorticoid hormone that raises blood glucose by stimulating gluconeogenesis and reducing peripheral glucose uptake. Stress also activates the sympathetic nervous system, releasing catecholamines like epinephrine and norepinephrine, which further elevate blood glucose. Therefore, hypoglycemia is not a typical complication of chronic stress.

B. The sympathetic nervous system response to chronic stress leads to vasoconstriction, increased heart rate, and elevated cardiac output, all of which tend to raise blood pressure. Persistent stress often contributes to hypertension, rather than hypotension.

C. Unrelieved chronic stress has a profound impact on the cardiovascular system. Prolonged activation of the HPA axis and sympathetic nervous system causes sustained high levels of cortisol and catecholamines, leading to hypertension, which strains the heart and blood vessels; increased heart rate, raising myocardial oxygen demand; endothelial damage and inflammation, contributing to plaque formation; and atherosclerosis due to lipid metabolism changes and chronic inflammation. These pathophysiological changes increase the risk of heart disease, including myocardial infarction, stroke, heart failure, and sudden cardiac death. Chronic stress also affects lifestyle behaviors, such as poor diet, smoking, and physical inactivity, which further exacerbate cardiovascular risk.

D. Chronic stress can lead to weight loss or weight gain, depending on individual metabolic and behavioral responses. Stress-related weight loss is often due to reduced appetite or increased metabolic demand, but it is variable and not the primary health complication associated with unrelieved chronic stress.

Rationale:

A. Scar tissue does not restore the original specialized cells of the tissue. Instead, fibroblasts produce collagen fibers to fill the wound, so the tissue loses some functionality and specialization.

B. Scar tissue lacks the normal structures of skin or tissue, including nerve endings. As a result, sensory perception is often reduced, not improved.

C. Scar tissue is primarily composed of dense, irregular collagen fibers, which provide structural strength but decrease tissue elasticity. This can lead to stiffness, restricted movement, or contractures in the area of the scar, especially over joints or large wounds.

D. Scar tissue is metabolically less active than normal tissue. Fibroblasts are active during healing, but once the scar is formed, it has low metabolic activity and does not function like the original tissue.