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STInside your inner ear live otoconia: microscopic crystals made of calcium carbonate (CaCO₃). These crystals sit on top of a gelatinous membrane inside two vestibular organs called the utricle and saccule. Their entire job? Detect gravity and linear acceleration.
Here’s how it works 👇
When you tilt your head or move forward, gravity pulls on these dense crystals. That force causes a shear between the otoconia layer and sensory hair cells beneath it. The hair cells bend, ion channels open, and the signal is converted into electrical impulses sent to your brain via the vestibular nerve.
Translation:
Your brain figures out which way is down by reading how tiny stones shift under gravity.
This system is so sensitive it can detect accelerations far smaller than what your eyes can see. It’s also why displaced otoconia can cause benign paroxysmal positional vertigo (BPPV)—when the “stones” roll where they shouldn’t, your brain gets false motion signals.
No magic. No intuition.
Just biomechanics + neurophysics + mineral chemistry working together so you don’t fall over every time you stand up.
💬 Question for you:
If humans evolved in low gravity (like Mars), how do you think this system would change?
#neuroscience #biophysics #anatomy #vestibularsystem #STEMeducation
@stem_antics
