Why does collagen synthesis decrease in dermal fibroblasts during prolonged exposure to high levels of cortisol, resulting in increased susceptibility to skin damage?

💡 Explanation

Cortisol inhibits the mTOR signaling pathway in fibroblasts, reducing protein synthesis, including collagen. Because collagen provides structural support in the dermis, reduced synthesis weakens the skin. Therefore, the decreased collagen synthesis leads to increased susceptibility to damage, rather than altered melanin, keratinocyte, or sebum production being the primary cause.

• Why does prolonged pressure on a nerve, such as sitting with legs crossed, lead to numbness and tingling sensations distal to the compression point?
• Why does hepatic stellate cell activation exacerbate liver fibrosis following chronic alcohol exposure?
• If a patient reports chronic pain despite lacking peripheral tissue damage, which mechanism best explains the heightened pain perception involving spinal dorsal horn nociceptors?
• What causes the disruption of sleep patterns following prolonged high cortisol levels, such as in Cushing's syndrome?
• A patient undergoing polysomnography shows reduced slow-wave sleep after prolonged exposure to bright light late in the evening. Which mechanism most likely explains this?
• If a mutation prevents rhodopsin from properly binding retinal in rod cells, which consequence follows regarding human vision in dim light?