32 articles tagged with #physiology
Hermann von Helmholtz formulated energy conservation, invented the ophthalmoscope, measured nerve impulse speed, and trained Heinrich Hertz. His full biography and science.
How cortisol and the HPA axis work, why the daily cortisol rhythm matters, what chronic stress does to the body, and what the evidence says about cortisol.
Why do we shiver when cold? Inside the hypothalamus, muscle thermogenesis, brown fat (BAT), fever shivers, and what infants do instead.
How the lungs move air, exchange oxygen and CO2, and what goes wrong in asthma, COPD, pneumonia, and at high altitude. A clear, evidence-based explanation...
What yawning actually is, why it's contagious, and why brain cooling — not oxygen — is the leading scientific explanation.
How the human heart pumps blood: chambers, valves, electrical conduction, cardiac cycle, and the most important diseases and treatments.
How hormones work: chemical messengers, receptors, feedback loops, key hormones such as insulin and cortisol, and the endocrine disorders that follow.
If atmospheric oxygen rose from 21% to 42%, paper would catch fire from a single spark, lightning storms would ignite vast wildfires, and giant insects might become possible — but the world would be a tinderbox.