Posts tagged brain

biomedicalephemera:

Standard procedure for work preparation:

1. Open skull.
2. Remove brain.
3. Go to work.
4. Replace brain with coffee.

[pathology image source]

The human brain, its nervous projections, layers, and cortical blood vessels

Though we’re probably subconsciously aware of our brains on a day-to-day basis, most of us generally don’t pay much direct attention to them. Of course, lots can go wrong in the mind, resulting in mental illness, physical illness, and in the worst cases, death.

But aside from everything that can go wrong in the brain, did you know that the mind, despite being only 2% of the average body mass, uses almost 25% of the oxygen we consume, and over 70% of the glucose we ingest? It’s a tiny organ, but it manages almost everything outside of the parasympathetic nervous system, and it requires a relatively high energy input (especially compared to other organs in the body) just to function on a daily basis.

The cells in the brain require, on average, twice as much pure energy as other cells, just to function, and when you’re focusing hard on a big paper, or trying to brainstorm and be creative, your mind is in overdrive! Even if you haven’t moved in two hours, if you’re focusing hard on an essay and coming up with lots of great ideas, your lunch isn’t going to last long, with what your brain is demanding.

Since it’s not a muscle, and you’re not necessarily doing anything physical when you think, it can be hard to believe that the brain needs so much energy.

However, the cerebellum, and especially the frontal and prefrontal cortices (where our personality and “creative minds” exist, for the most part) demand more energy than our stomachs, livers, spleens, and kidneys combined! Depending on how your brain is wired, that fact can make it extremely exhausting to deal with other people, as you’re engaging your prefrontal cortex to a high degree. Thinking hard and being creative can sap your energy, too - that’s why I always had an apple or banana to eat midway through my morning courses!

Tabulae Anatomicae. Bartholomeo Eustachi, 1570 (Published 1783).

The Anatomy of the Brain, Explained in a Series of Engravings. Charles Bell, 1803.

If I've asked you this already, I've forgotten and missed your response--could you direct me to it? If not, then here's my question: When I was four, my brother hit me in the forehead with a baseball bat (it was an accident, no worries.) When my mom looked at the wound, she said she saw white. Was that my skull she was looking at, or something else? — Asked by dreamerlogic

I looked back, and you haven’t asked this yet, if it’s any consolation to my long response time! ><

She may well have seen the skull. As the dermis + epidermis can be less than 0.5-1 mm thick along the skull, and as children tend to have very thin subcutaneous fat layers on the forehead, it’s easy for a bat to break through all of the layers that are present. My own brother had the skin on his lower jaw busted straight through around the same age - while it required a few stitches, at least the bones are more resilient than the skin!

biomedicalephemera:

1862. Private Patrick Hughes, Co. K, 4th New York Volunteers, was wounded at the battle of Antietam.
Private Hughes survived, but when he sneezed, a cone would protrude from the wound site.

biomedicalephemera:

1862. Private Patrick Hughes, Co. K, 4th New York Volunteers, was wounded at the battle of Antietam.

Private Hughes survived, but when he sneezed, a cone would protrude from the wound site.

Rebloggable for the anon with CLASSY ASKS. ;P

Rebloggable for the anon with CLASSY ASKS. ;P

Dear Early Morning Anon: I still have no idea, nor am I sure I want to have an idea, of what you were talking about. But perhaps these helpful onlookers can lend a hand - these were the three most common structures suggested. That said, I have absolutely no clue how the corpus callosum would function as a “sex toy” (if I were forced to choose…), as it’s just a band stretching from one hemisphere to the other, essentially.

Top right: Fornix of the brain
Bottom left: Corpus callosum
Bottom right: Medulla oblongata (aka the lower brain stem)

There are also two structures in the vagina known as a fornix, but as "fornix" simply means "arch" or "vault" in Latin, I’m not sure that’s incredibly relevant.

whats that structure in the brain that looks like a sex toy called? — Asked by Anonymous

I don’t even…what are you talking about? The whole brain? None of it? The brain stem? the cerebrum? I really would…actually, I’m not sure if I want clarification on what you’re asking.

There are a lot of structures in the brain, but unless you’re into squishiness, I don’t think any of them would make particularly good sex toys. Just sayin’?

biomedicalephemera:

De humani corporis fabrica libri septem. Andreas Vesalius, 1543.

biomedicalephemera:

De humani corporis fabrica libri septem. Andreas Vesalius, 1543.

Anatomical Teaching Models

It’s believed that anatomical models have been used for teaching purposes (as opposed to ritualistic or religious purposes) since some point between 100 BCE - 300 CE, since dissection of the dead was a taboo and crime in the Late Greek and  Roman empire, and paper or vellum for illustration was much more fragile than, say, carved wooden figures.

However, most of our evidence for anatomical models comes from the late Medieval era and later, when materials such as ivory and sealed papier-mâché were used for many anatomical carvings. Later, especially in the 18th and 19th centuries, wax sculptures were common in medical schools, as much finer detail was attainable with such a pliable substance.

Today, most models used for teaching both lay persons and students are made from thermoplastics and texturing agents, and can range from highly detailed micro-premature babies, to fully-removable models of life-sized animals with every layer of tissue and organs, to huge versions of virions not normally visible except under an electron microscope. Given that the majority of students show greatly increased memory of a subject when able to physically manipulate a representation of it, the use of anatomical teaching models is here to stay.

For more on anatomical models and tons more on the history of medicine, visit the Science Museum: Brought to Life!

Images:

Top: Anatomical structure of reclining woman in early pregnancy. Florence, Italy, ca. 1770.
Center left: Wax model of the human brain, with skin, skull, and meninges removed. Intended for medical students. Western Europe, ca. 1700-1900. Date uncertain.
Center right: Papier-mache model of acupuncture meridians. Japan, ca. 1601-1700.
Bottom left: Sculpture of male black infant, 22-23 weeks development. Created for exhibit on how micro-preemies are kept alive in the modern era. England, 1998.
Bottom right: Model of an adenovirus, magnified 3,000,000x, from electron microscope images. London, England, 1985.

ragingkitten:

biomedicalephemera:

“Koalo” (Koala - Phascolarctos cinereus)
Sure, it lives its life in trees, dines almost exclusively on a plant genus that is incredibly non-nutritive and toxic to most animals (Eucalyptus), and the males have a two-pronged penis, but the koala has more in common with humans than you might think.
For one, they have lots of problems with venereal diseases, including one that’s so closely related to the human strain it can be transmitted across species - chlamydia. However, in koalas, chlamydia is present even in most healthy animals, and it’s only when the animal gets stressed or otherwise weakened that it manifests as disease. There’s currently a huge uptick in the numbers of koalas infected with chlamydia, causing mass sterility and, in many cases, death.
On a less dire note, koalas are the most distantly-related mammal to display “dermatoglyphes” - fingerprints with ridged loops and whorls, like humans have. In fact, it’s almost impossible to tell the difference between the two under a microscope. As Homo sapiens and Phascolarctos cinereus diverged over 70 million years ago, it’s clear that this is a case of convergent evolution, developed to help the koala grip onto branches and tree trunks.
Aracana, or, The museum of Natural History. George Perry, 1811.

Those cute little Koalas? Kids, don’t play with them, you’ll get chlamydia. 

Not to mention they&#8217;re pretty much jerks who will act all cute and cuddly until you get within biting distance. The only time they&#8217;re not total jerks is when you have something they direly need. They&#8217;re way smarter than they should even have the capacity to be.
Fun fact: The koala&#8217;s low-nutrition diet means that it gets very little energy, and the brain is a massive energy sink. As a result, in the past few thousand years, the koala&#8217;s brain has shrunk to the size of a walnut, leaving most of its cranial cavity filled with cerebrospinal fluid, and the koala with one of the smallest brains for its size among mammals - just 0.2% of its total mass.

ragingkitten:

biomedicalephemera:

“Koalo” (Koala - Phascolarctos cinereus)

Sure, it lives its life in trees, dines almost exclusively on a plant genus that is incredibly non-nutritive and toxic to most animals (Eucalyptus), and the males have a two-pronged penis, but the koala has more in common with humans than you might think.

For one, they have lots of problems with venereal diseases, including one that’s so closely related to the human strain it can be transmitted across species - chlamydia. However, in koalas, chlamydia is present even in most healthy animals, and it’s only when the animal gets stressed or otherwise weakened that it manifests as disease. There’s currently a huge uptick in the numbers of koalas infected with chlamydia, causing mass sterility and, in many cases, death.

On a less dire note, koalas are the most distantly-related mammal to display “dermatoglyphes” - fingerprints with ridged loops and whorls, like humans have. In fact, it’s almost impossible to tell the difference between the two under a microscope. As Homo sapiens and Phascolarctos cinereus diverged over 70 million years ago, it’s clear that this is a case of convergent evolution, developed to help the koala grip onto branches and tree trunks.

Aracana, or, The museum of Natural History. George Perry, 1811.

Those cute little Koalas? Kids, don’t play with them, you’ll get chlamydia. 

Not to mention they’re pretty much jerks who will act all cute and cuddly until you get within biting distance. The only time they’re not total jerks is when you have something they direly need. They’re way smarter than they should even have the capacity to be.

Fun fact: The koala’s low-nutrition diet means that it gets very little energy, and the brain is a massive energy sink. As a result, in the past few thousand years, the koala’s brain has shrunk to the size of a walnut, leaving most of its cranial cavity filled with cerebrospinal fluid, and the koala with one of the smallest brains for its size among mammals - just 0.2% of its total mass.

Top: Cranial Nerve I (Olfactory Nerve) Branches in the Nasal Cavity
Bottom: Base of Brain - Olfactory Nerve and Optic Chiasma Emphasized

Ever wonder why you don’t think of an event or memory for years at a time, but the unexpected whiff of a familiar smell can bring it all flooding back?

The olfactory (smell-processing) nerve is the first (I) of the cranial nerves, and is, like the other cranial nerves, directly connected to the brain. However, unlike the others, the cortex of the brain where scent is processed is not near the back of the brain. It is between the frontal and temporal lobe, very close to the long-term memory centers, and the optic olfactory nerve passes directly below the optic nerve. As such, smells can often trigger strong visual and emotional memories that had a unique scent involved, even if you didn’t notice the scent at the time.

Despite the human’s relatively weak and somewhat-insignificant sense of smell, it’s still considered the sense most closely associated with all episodic (event) long-term memories. Certain smells have been known to bring back memories more than half a century after the event occurred.

Anatomy, Descriptive and Surgical. Henry Gray, 1911.

Median Section of Skull
Showing middle meningeal artery and significant planes of skull. Dura mater that would be visible in typical median section not depicted.
Anatomy of the Brain and Spinal Cord. Harris E. Santee, 1907.

Median Section of Skull

Showing middle meningeal artery and significant planes of skull. Dura mater that would be visible in typical median section not depicted.

Anatomy of the Brain and Spinal Cord. Harris E. Santee, 1907.

That's one of the reasons why I tink the liver is just one of the coolest organs. Metabolizes drugs, helps with digestion, can regrow... the list goes on. I'm probably going to have to go with the typical answer and say the brain. Just thinking about how much it does day and night baffles me. Dreaming, emotions, pain, involuntary muscle actions... just one organ that controls all of that. Fascinating. — Asked by dammitandrea

As much as I love the brain, and am amazed by its powers of rewiring and re-building itself after disaster or to accommodate new input, I’m still more a fan of the liver. The metabolism of toxins is so fascinating…plus there’s the whole “starfish-y” aspect of it, which is nifty as hell.

Standard procedure for work preparation:

1. Open skull.
2. Remove brain.
3. Go to work.
4. Replace brain with coffee.

[pathology image source]

Vault of the Skull Opened, Showing the Falx Cerebri and Tentorum
The falx cerebri is a strongly-arched section of dura mater which separates the two hemispheres of the brain. Combined with the tentorum ceribelli, it supports and separates the primary sections of the brain (cerebellum, right cerebrum, and left cerebrum). The large open section in the center of the meningeal conjugation is where the corpus callosum passes from one hemisphere of the brain to another.
Applied Anatomy. Gwilym Davis, translated by Erwin Faber, 1910.

Vault of the Skull Opened, Showing the Falx Cerebri and Tentorum

The falx cerebri is a strongly-arched section of dura mater which separates the two hemispheres of the brain. Combined with the tentorum ceribelli, it supports and separates the primary sections of the brain (cerebellum, right cerebrum, and left cerebrum). The large open section in the center of the meningeal conjugation is where the corpus callosum passes from one hemisphere of the brain to another.

Applied Anatomy. Gwilym Davis, translated by Erwin Faber, 1910.