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Eye Floaters Explained by Robert Sapolsky

Time: 00:28:32 Question 2 (Eye floaters) at:  https://www.youtube.com/watch?v=5ib2QbIfx7k Summary: Robert Sapolsky explains that many common beliefs about eye floaters are misconceptions. Although floaters appear to be tiny particles drifting across our vision, they are not bits of cellular debris, they are not on the surface of the eye, and we are not directly seeing them. Instead, floaters are shadows cast by structures inside the eye. The inside of the eye is filled with a clear, gel-like substance called the vitreous humor, which contains a microscopic three-dimensional framework of collagen fibers. As people age, the gel gradually shrinks and changes, causing collagen fibers to move closer together and stick to one another. These collagen aggregates become large enough to cast shadows onto the retina, creating the appearance of floating specks or threads. The apparent movement of floaters is also misleading. The collagen itself is embedded within the vitr...

Mitochondria as Central Regulators of Human Physiology and Disease: Implications for Immunity, Neurological Function, Sensory Systems, and Cellular Homeostasis

Revision:  Abstract Mitochondria generate ATP while regulating calcium signaling, apoptosis, metabolism, immune responses, and reactive oxygen species (ROS). Because organs with high energy demands—including the brain, heart, skeletal muscle, retina, cochlea, liver, endocrine glands, and immune system—depend heavily on mitochondrial function, mitochondrial dysfunction contributes to aging and diseases affecting multiple organ systems. This review summarizes the roles of mitochondria in neurodegeneration, immunity, circulation, endocrine physiology, muscle and skin homeostasis, vision, hearing, mitochondrial genetics, and emerging therapeutic strategies. Introduction Mitochondria evolved from an ancestral bacterium through endosymbiosis approximately two billion years ago and remain indispensable for eukaryotic life. In addition to ATP production, they regulate calcium homeostasis, apoptosis, redox balance, innate immunity, and metabolic adaptation. Although mitochondria possess the...