11.06.08
A Fresh Look at Wrinkles
A Fresh Look at Wrinkles
While I usually write about my favorite organ, the skin, the recent US election has led me to ruminate on another organ, which thankfully won the day. Here are some fun and interesting facts about each.
Weight
The skin of an average adult weighs 8-10 pounds, or about 12-15% of body weight.
The average human brain weighs 3 pounds, or about 2% of total body weight.
Surface Area
The skin covers an average surface area of 1.5 to 2 square meters.
The total surface area of the human cerebral cortex is about 2,500 cm2, or about the size of a pillow case (approximately 40 cm by 62.5 cm).
The surface area of the brain, not its total volume, determines how many neurons and synaptic connections it can store. The female brain has deeply folded areas which might compensate for the larger overall size of the male brain. And this is where the topic of wrinkles re-enters the arena.
Wrinkles
Wrinkles form over time as the skin thins and the epidermis sags, due to loss of collagen and elastin in the dermis (among other things). Darker skins, which are thicker, tend to wrinkle at a slower rate than thinner, fairer skins. Skin wrinkles are a sign of age, and their appearance often leads people to find relief in the needle—the Botox needle that is.
In stark contrast, wrinkles in the brain are desirable, indeed, necessary. For example, a rare disease called lissencephaly (’’smooth brain”) is a lack of complex brain folding linked to mental deficiency.
A highly wrinkled cerebral cortex increases the surface area of the brain and thus the number of neurons that may be contained within it. However, though a multiplicity of wrinkles seems to be what makes humans smarter than (most) other animals, it does not explain what made Richard Feynman smarter than most of us. Though convoluted human brains pack larger surface areas into smaller containers, it is the branching of brain cells and the formation of complex links between them that apparently tells the tale.
Our new POTUS scores very well on the wrinkle index: highly wrinkled on the inside and smooth on the outside. However, let me be the first to predict that the burdens of office will soon outweigh his thicker skin advantage with respect to external smoothness, though I suspect he’ll wear each new wrinkle like a badge of honor incurred in our service. Perhaps he’ll even be responsible for a decrease in the popularity of Botox. Welcome to a post-racial society, where wrinkles, definitely internal and maybe even external, rule.
