Fascinating post by Rick Wayne
Originally shared by Rick Wayne (Author)
Dissection of the head and neck is undoubtedly the most difficult part of gross anatomy, and it’s not just the density of nerves and blood vessels — it’s their torturous course! They move through, around, over, and in and out of muscle, ligament, and especially bone. The plates of the scalp are highly porous and full of tiny foramen, holes that exist specifically for the passage of certain vessels or nerves. And you need to understand, it doesn’t look like this in class. A preserved cadaver is exsanguinated and steeped in formaldehyde, a process that turns everything into various shades of taupe and tea-brown. A tiny collapsed artery looks almost identical to a nerve fiber of the same size.
But all of this complexity exists for a reason. It makes sense to encase the brain in a protective shell, which means no direct lines between things. They have to go in and around through tiny holes that exist just for their passage. It also makes sense to keep the primary sensory systems, which are tethered to the brain by some pretty heavy duty wiring, close to it. All that wiring has to be deployed somewhere. And wiring int he body only carries signals, not power. In fact, it USES power. A lot of it. So that means we need a large, always-on power supply — here supplied almost directly from the heart in two large tubes, the carotid arteries.
In fact, pound for pound, your brain consumes more energy than any other organ, even large, metabolically-active ones like your intestines and liver. In the average case, the brain makes up about 2% of weight but uses 20% of your daily caloric need. Note, that leaves 80%
the bulk of your daily energy requirement – for things like digesting food, anabolism and catabolism (making shit and breaking it down), filtering of blood, replacement of senescent blood cells, maintaining an immune barrier, and so on. Your muscles, however, are highly efficient and so moving around actually doesn’t burn all that many calories, which is why you have to move around A LOT to burn anything significant. (Also, just for clarity, note that the brain uses 20% of your need , not your intake.) All of that becomes clear once you pump the blood vessels full of hard resin and dissolve the rest of the tissue away. You can see the scalp and the gap left by the skull but remember, bone is still living tissue, and in fact it’s the only tissue that replaces itself when damaged. You can see the sockets of the eyes, the curve of the tongue down the throat, and the blood bath that is the brain. Sitting there. Steeped in it. Soaking everything in. Like a termite queen – fat and motionless, well-fed, pulsating ever-so-slightly in time with your heart, laying dream-eggs and armies of desire.