Abstract
The mammalian ear has an extraordinary capacity to detect very low-level acoustic signals from the environment. Sound pressures as low as a few μPa (−10 dB SPL) can activate cochlear hair cells. To achieve this sensitivity, biological noise has to be minimized including that generated by cardiovascular pulsation. Generally, cardiac pressure changes are transmitted to most peripheral capillary beds; however, such signals within the stria vascularis of the cochlea would be highly disruptive. Not least, it would result in a constant auditory sensation of heartbeat. We investigate special adaptations in cochlear vasculature that serve to attenuate cardiac pulse signals. We describe the structure of tortuous arterioles that feed stria vascularis as seen in corrosion casts of the cochlea. We provide a mathematical model to explain the role of this unique vascular anatomy in dampening pulsatile blood flow to the stria vascularis.
Highlights
Without a stethoscope, we do not normally hear our own heart beat, there are some pathological conditions when it can be heard
The present study explores the physical properties of vascular supply to stria vascularis and the adaptation of this system to attenuate cardiac pulse transmission
We strongly suggest that the vessel convolutions serve to attenuate cardiovascular pulse signals reaching the capillary beds stria vascularis
Summary
We do not normally hear our own heart beat, there are some pathological conditions when it can be heard (e.g., high blood pressure, pulsatile tinnitus, and superior semicircular canal dehiscence) In these cases, the perceived heart sound is usually the result of signals from arteries external to the cochlea rather than pressure changes generated within cochlear vessels. The cochlea appears to have a unique blood supply vasculature that ensures a dampening of cardiovascular pressure changes, essentially converting a pulsatile flow to a more linear stream The requirement for this damping mechanism is obvious given the sensitivity of cochlear hair cells to detect mechanical signals. The most direct blood supply to the organ of Corti is sparse, typically a small arteriole running adjacent to the basilar membrane This may be one adaptation to keep pulsating vessels away from hair cells. The dense capillary network of the stria vascularis is richly supplied, and it is these feeding vessels that are described and modeled in the present study
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
