Lesson 1: Organization of the Human Nervous System

You faggots studying diligently for your MCAT? No, you're here, your dick is in your hand, and you've got loli and furry porn in 31 other tabs. Pay attention; I'm gonna help you. If this gets enough attention, I'll make it a thing. You ready? Let's do this.

The nervous system has two primary divisions: the central and peripheral nervous systems. (pic related) The CNS is comprised of the brain and spinal cord, while the PNS (hehe) is comprised of nerve tissues and shit OUTSIDE the brain and spinal cord. This includes 10 out of 12 pairs of cranial nerves (the optic and olfactory nerves are outgrowths of the CNS; we’ll cover that shit in future posts) and all 31 pairs of spinal nerves. Sensory, or AFFERENT neurons, send sensory info from receptors to the CNS. Motor, or EFFERENT neurons, send motor info from the CNS to your muscles and glands. There’s also a third type, interneurons, which are found between other neurons and are numerous as shit. (MNEMONIC: Afferent neurons ASCEND to the CNS, and efferent neurons EXIT to the rest of your body.)

The PNS (hehe) has 2 subdivisions: the somatic and autonomic nervous systems. The somatic nervous system is comprised of sensory and motor neurons scattered across your skin, nerves, joints, and muscles (like you have any, fag).
The autonomic nervous system (ANS) controls the muscles you’re not conscious of-the ones that regulate digestion, heartbeat, breathing, glandular secretions, etc. The automatic shit. That’s a good way to remember it, actually. “Autonomic” and “automatic” both share the root word “autos,” meaning “self,” which is why you’re fucking autistic.
Now, the ANS has further subdivisions: the sympathetic and parasympathetic nervous systems. Think your puny brain can handle all this? These two are antagonistic, meaning that they work against one another. For example, the sympathetic nervous system would amp up your heart rate and relax your bronchi, while the parasympathetic one would slow down your heart and constrict the bronchi.

The parasympathetic nervous system is there to conserve energy, and as such, it’s associated with rest and sleeping. You probably use this one more. It also acts to stimulate peristalsis in digestion and exocrine secretions. “Rest-and-digest,” basically. It:
>constricts your pupils
>stimulates saliva (you drooling retard)
>stimulates bile release
>contracts your bladder
>stimulates peristalsis and secretion
>constricts bronchi
>slows your heart
The sympathetic nervous system, on the other hand, is brought into play by stress. You know the phrase “fight or flight?” That shit. It:
>dilates pupils
>inhibits salivation (you should use it more)
>inhibits bladder contraction
>relaxes dem bronchi
>ramps up your heart rate
>inhibits peristalsis and secretion
>stimulates sweating and piloerection (no, not “pillow erection; that’s your dakimakura)
>stimulates glucose release and production
>stimulates orgasm (hey, maybe you do use this one)
>stimulates secretion of adrenaline and noradrenaline

The brain is covered with this thick sheath of connective tissue called "meninges." This shit keeps the brain anchored in the skull, reabsorb cerebrospinal fluid, and generally protect that brain of yours. There's three layers to them: the dura mater, the aranchnoid mater, and the pia mater. Cerebrospinal fluid is the solution inside which the brain and spinal cord rest, and it's produced in little cavities called "ventricles" inside the brain.

Onto the brain itself. It's got 3 basic subdivisions: the hindbrain, midbrain, and forebrain. In evolutionary terms, the hindbrain and midbrain came earlier, and are thus more "reptilian" parts of the brain (BILL CLINTON IS A RAPIST INFOWARS DOT COM). Together, they're the BRAINSTEM, which is primitive as shit. The forebrain came later, including the LIMBIC SYSTEM, which is associated with emotions and memory. The most recent development is the cerebral cortex, which-fuck it, I'm greentexting this, too.

FOREBRAIN:
>Cerebral Cortex-Complex behavioral, perceptual, and cognitive crap
>Limbic System-Emotions and memories
>Basal Ganglia-Movement
>Thalamus-Sensory "relay station"
>Hypothalamus-Hunger, thirst, emotion (yeah, i know I said emotion earlier; shit's complicated)

MIDBRAIN:
>Inferior colliculus-gets sensory info from the auditory system
>Superior colliculus-visual sensory input

HINDBRAIN
>Cerebellum-Refined motor movement
>Medulla oblongata-Vital functions (breathing, for instance)
>Reticular formation-Arousal and alertness

Details to come. Lemme piss and take a smoke.

Oh, and lemme throw this in first: The brain starts of as the neural tube when you're a fetus. Early on, that's comprised of 3 swellings that become the hindbrain, midbrain, and forebrain. See pic related.

All right, nicotine time.

Not a science. Only physics and chemistry + math allowed. Sorry brainlet and better luck next life.

>In evolutionary terms, the hindbrain and midbrain came earlier, and are thus more "reptilian" parts of the brain
I'm not 100% d'accord with you on that, it's more like a fish brain instead of a reptile brain. the reptilian brain thing relies heavily on optic/olfactory inputs, which are not brainstem-related afaik

All right; I'mm back. Marb golds burn way too fucking fast.

Yeah, true. That was a throwayay joke because I'm gonna get bored if I'm not allowed to sperg out while typing this. Thanks for actually reading this.


>implying they don't test on this
Physics and math is the next lesson. I'll vary it up so we don't get sloppy on one subject. Oh, and they test "behavioral sciences," too, which Veeky Forums is gonna hate. Not bothering with verbal reasoning. Learn to read.

The hindbrain (SEE: rhombencephalon) is for balance, motor coordination, balance, digestion, breathing, and sleep/wake processes. Basically, vital functions. In mommy's tummy, the rhombencephalon divides to become the myecephalon (SEE: medulla oblongata) and the metencephalon (SEE: pons, Sarah Bellum).

The MEDULLA OBLONGATA is a lower brain structure that controls vital functions like breathing and heart rate. The PONS is above that, and it contains sensorimotor pathways between the medulla and cortex. In the back of the pons is the CEREBELLUM, which basically controls shit like posture, balance, speech refinement (i.e. not slurring), and coordination. Alcohol affects the cerebellum. Make inferences from that.

*myelencephalon (I'm amped as shit right now.)

MIDBRAIN:

This lies above the hindbrain. It receives sensorimotor info from the rest of your body. Involuntary reflexes resulting from noise and shit you see are associated with this.

FOREBRAIN:
Above THAT is the forebrain (SEE: prosencephalon), which is associated with the complex cognitive and behavioral processes that are characteristically human. In mommy's tummy, the prosencephalon divides to form the telencephalon (cerebral cortex, basal ganglia, limbic system, reeeee) and diencephalon (thalamus, hypothalamus, posterior pituitary gland, pineal gland)

>Chemistry
>Math
>Sciences
top kek

Now onto the bits and pieces comprising the forebrain (DUN DUN DUUUNNNN). This is the most recent portion in evolutionary terms, and by weight and volume, it's the biggest. This is shit derived from the diencephalon (thalamus, hypothalamus, posterior pituitary gland, pineal gland) and the telencephalon (limbic system, basal ganglia, cerebral cortex).

DER THALAMUS
Basically a way/relay station for all sensory info except scent. After it receives that shit, it sends it along to the cerebral cortex.

DER HYPOTHALAMUS
Subdivisions:
>lateral
>ventromedial
>anterior

This is for the "four F's": Feeding, Fighting, Flighting, and Fucking. Those help maintain homeostasis.

Let's describe these in terms of what happens if you get, say, a gunshot to any given one:
>Lateral hypothalamus (LH): You Lack Hunger
>Ventromedial hypothalamus (VMH): You're Very much Hungry
>Anterior Hypothalamus (A): You're Asexual

In other words, the lateral hypothalamus is the hunger center that has special receptirs indicating when you need more food or fluid, the ventromedial hypothalamus is the "satiety center," and the anterior hypothalamus controls being horny (also, sleep and body temperature.)

Right?

The diencephalon also become various connecting pathways, the posterior pituitary gland, and the pineal gland (IT'S YOUR THIRD EYE BRO JUST SMOKE WEED NO DON'T TELL MOM).

The posterior pituitary gland is the place from which hypothalamic hormones vasopressin (or ADH, or "antidiuretic hormone") and oxytocin (the "hug hormone"), and it's made up of axonal projections from the hypothalamus.

The pineal glad plays a role in a number of biological rhythms, including your circadian rhyth, which is probably way the fuck off. It secretes meletonin, brah, and it recieves signals from the retinas in your eyes to coordinate that with sunlight.

Holy fuck, these typos are multiplying. Anyway...

BASAL GANGLIAAAA
These coordinate muscle movement by receiving info from the corex and relaying it via the EXTRAPYRAMIDAL MOTOR SYSTEM to the brain and spinal cord. That system in all caps takes info about your body's position and carries it to the CNS. Notably, Michael J. Fox's Extrapyramidal Motor System is all fucked-up, which is why he moves like a goddamned spastic.

The limbic system (see pic, then it's back to bewbs) is a bunch of interconnected structures all looped around the center of the brain and is primarily all about memory and emotion. You've got:

>septal nuclei
>amygdala
>hippocampus

I mean, there's more to this, but let's leave that for another thread.

SEPTAL NUCLEI
Pleasure center. Run a current through that shit for a braingasm. Has a role in addictive behavior; stimulated when you fap to dickgirls.

AMYGDALA
Defensive/aggressive behaviors; fear and rage.

HIIPOCAMPUS
Consolidates info into long-term meories and then sends remote memories to the cerebral cortex. Communicates with the other parts of the limbic system through a lon projection called the fornix.

Take note of that olfactory bulb, too. Ever wonder why smells are so emotional and nostalgic?

The outer surface of the brain is known as the cerebral cortex, or neocortex (CRASH BANDICOOT, FOR THE LAST TIME, GIVE ME THE CRYSTALS!). This has a bunch of raised bumps and folds known respectively as gyri and sulci. All those convolutions mean increased surface area for the brain. The cerebrum has 2 halves, or hemispheres. (see pic, I lied)

The frontal lobe has 2 basic regions: the prefrontal cortex, which supervises and directs the functions of other regions of the brain, and the motor cortex, which controls voluntary movements.

The prefrontal cortex is like a supervisor for long-term planning, impulse control, memory, emotion, and perception. Since it combines and integrates info from multiple cortical regions, the prefrontal cortex is considered an ASSOCIATION AREA. This is in contrast to a PROJECTION AREA, which governs simpler tasks, like the visual or motor cortex.

There's also the Broca's Area, which is key in speech production and is usually found only in one hemisphere depending on which one is dominant.

The parietal lobe, which is to the rear of the frontal one, contains the somatosensory cortex, which is involved in somatosensory info processing. This area is considred a projection area, and is sorta like a tactile center. It receives info regarding temperature, touch, pain, and pressure. Together withthe motor cortex, this forms the "sensorimotor cortex."

The central bit of the parietal lobe, on the other hand, is associated with spatial reasoning and one's sense of orientation.

I should probably post this.

Okay, one more smoke break because I'm a goddamned junkie, and then it's onto the occiptal and temporal lobes.

Thank you OP for this post please make it a thing and post often

Will gladly do. It helps me, too.

Ooh, meta-dubs. All right, we're powering through to the end if it kills us, which it very well might if I drink more Monster.

The occiptal lobes, at the back like Rosa Parks wasn't, contain the VISUAL CORTEX, or STRIATE CORTEX. "Striated" means "striped," which'll come up again when we cover muscles. This area, obviously, processes visual information, but it's also been implicated in motor control and learning.

The temporal lobes contain a lot of shit, actually. The auditory cortex, locate there, is where sound gets processed. Wernicke's area is key in language comprehension and reception. The temporal lobe also plays a part in processing memories, emotion, and language. The memory bit makes sense because this is located inside the hippocampus.

Now, one side of the brain usually talks to the opposite side of the body (i.e. left-brain governing right-handedness). We call that contralaterality. There are exceptions though: ipsilaterality. Hearing is an example of this.

A person's DOMINANT hemisphere (generally the left one) is the one that performs most analytic functions, like math and language. (See: Broca's area; Wernicke's area)

The nondominant hemisphere is the one associated more with creativity, spatial processing, and intuition.

VISUAL
>Dominant-letters, words
>Nondominant-Faces

Auditory
>D-Language; phonemes and sounds
>ND-music

Language
>D-speech, reading, writing
>ND-emotional content, tone

Welp, that's it for that...

Are you literally aspergers?

Tune in next time for Lesson 2: Fundamental Units. I'm gonna go kill this pack and crash now.

Yes. In the most literal sense, I have Asperger's Syndrome. I mean no. I am not, as a person, literally Asperger's, the syndrome. That's more of an abstract concept than a physical body like me.

I am sure you are lying. You are literally the syndrome. How emotional are you? Can I toy with your emotions?

I'm actually pretty emotional and warm in-person. It's not like we don't have feelings. It's just that most of us have trouble getting on a neurotypical wavelength in order to communicate. My sperg manifests more in my interests and in sensorimotor shit than in anything else. I'm just wired differently.

Still, this conversation wouldn't be very relevent to the thread except laterally, or appropriate for the board at large, so I'm not gonna continue it here beyond this post.

I could move our convo over to /r9k/ or /b/ or something if you'd like to talk about my autism or try to pick on me or whatever, though. Would you like that?

Yes I have questions but I dont think anyone cares if it is on sci or other board and dont even try to get it into b because that would mean it will be up only for 10 minutes max or there will be mentally stunned faggots posting shit. This board is appropriate. It is a syndrome after all therefore scientifically related topic. Please dont tell me you cant have two topics in one board and that is also a manifestation of your autism.

I would be interested in answers to this if you mind:
Are your emotions on the same level as other peoples in your opinion? When did you find out about your interest in human biology?(only nervous system or something else?). Do you know the difference between aspergers and high functioning autism, I mean do you speak with other less functioning autists? Can you be independent financially and is it hard for you to do everyday life stuff? How good are you at reading other peoples behavior and can you effectively learn to read gestures, tones of voices, sarcasm and such?

Im a psychfag.

Eh, all right. It'll at least bump the neurological stuff to the front.

>Are your emotions on the same level as other peoples in your opinion?
Yes. I'm capable of feeling the whole spectrum of human emotions, and I can distinguish easily between nuanced emotions like nostalgia, grief, and feeling blue instead of just saying "sad."

>When did you find out about your interest in human biology?
I dunno. I guess when I was a kid (4-5-ish.) I liked to watch documentaries and educational programs a lot, and I had a lot of books about the subject. And I'm interested in all of academia.

>Do you know the difference between aspergers and high functioning autism, I mean do you speak with other less functioning autists?
Yes, I know the difference. And yes.

>Can you be independent financially and is it hard for you to do everyday life stuff?
I'm more capable of pretty much everything than pretty much everybody I know at pretty much everything, and I had 10k in the bank before I graduated high school. I get overwhelmed easily by sensory input, but I've learned to cope. I do dress myself badly, though, and I'm rather messy.

>How good are you at reading other peoples behavior and can you effectively learn to read gestures, tones of voices, sarcasm and such?
I'm far too trusting and don't really get body language, but I understand sarcasm, and I get around my deficiencies by being as sincere and literal as possible. I also think I pick up on things that people normally don't.

Do you happen to work in a field you study? It seems like your interest is a very fortunate one. I know few high functioning autists whose interests are very impractical but they are not aspergers so that could make the difference in their "successfulness" in life.

I would like to point out that a lot of non autistic people dont get body language at all. It can be learnt to a degree. I am going to assume you cant count on your instincts on nonverbal communication, is that correct? You are very intelligent which would mean you can learn behavioral patterns intellectually if you can train your focus and perception to notice them in life. If you can understand nonverbal behavior in animals you could do that with people too.

Being literal as possible is not always effective. Especially when trying to understand other people as people will give different meanings to words. People will often use words not in logical or correct meaning but based on their experiences and what they heard it means. Sometimes as expressions or more like symbols for meaning.

Do you have scheduled day to some degree? Can you stand uncertainty in everyday life? Do you need rituals in life (in psychological meaning)? Can you control your emotions to any degree? Do you misunderstand what people meant often?

Just what i wanted. Neurology taught in the style of cancermeme recipe images.

Why is DMT literally just melatonin minus a co2 molecule and couldnt i extract tryptophan from a turkey and carboxylate it and then chase an amide into it with an acid to make DMT?

I'm not OP but I'm actually a 3rd year med student and I do have high functioning aspergers (Im not socially awkward or anything). Ask me anything you want.

Sure. What is your atypical behavior? If you are not socially awkward I am going to assume a common guy will not spot your aspergers.

Solid thread, I've used Veeky Forums to reaffirm knowledge before but that's pretty next level, I think you went a bit overboard on the Adderall too.

If you could explain the neurophisiology of the vestibular apparatus in terms of pepe memes I'd be very thankful too.

Well, sometimes social cues aren't my forte. But it's very nuanced. Like I'll joke loudly in public with friends.

I'm savant tier at math and physics too. I am very bad at small talk and plan out what I say before I say it. I also stutter occasionally .

Good explanations but sadly for me, the last thing I need to revise is the nervous system. I always get a 132/131 on practice exams on the chapter.

Now physics two material like voltage and circuits, sound waves and such I'm lost on as I haven't taken the class. Thermodynamics I could brush up on too along with actually useful tips for the CARS section.

I bet you look like Achmed the anorexic Third-World computer nerd. Keep staring at weird irrelvant mathematical shapes and pondering how thorium can get you laid. Pass.

Also,

.... why do all of you autistic poser pre-meds learn shit this way? Just shut up and walk the process.

Here, have some axial slices and learn the way we actually practice.

>axial slices are on the MCAT

sure thing hotshot

Not OP but I've always found I tend to learn better by looking at the over exaggerated and more detailed renditions then comparing it to real images as it gives me a sense of how much variance to expect in normal brains. If I just look at MRI scans then I have no picture perfect anchor point to go off of and compare it too. Not to mention you simply can't get a good grasp of the 3D structure from looking at only MRI.

the mcat contains anatomy/physiology/etc questions? when do americans study this?

Not OP buy physiology for sure but the MCAT only directly tests the most basic anatomy which is very little. A decent bit of what OP went over won't be directly tested on the MCAT with some of the finer details of like the different parts of the hypothalmus for instance but it still could be on the MCAT and honestly it just helps knowing it all to get a more full picture of the function of the nervous system.

See the MCAT is mostly passage based questions. Now the question could just use the passage to rephrase knowledge that you have to know and isn't found in the passage directly. For example, X is found in the nucleus to stimulate transcription, which of the following would be most likely to also stimulate transcription? So you have to know steroids and steroid like tyrosine hormones act at the level of transcription and then you have to pick out the steroid hormone from the list.

Or it might ask something directly based on the passage. The passage could be based on anything from a random protein's function you've never heard of or a lesion to a very specific part of the brain. Either way it will be written in a scientific paper form and you have to interpret results and conclusion. Here you see questions like which of the following if true would most hurt the experimenters hypothesis or simply what do the results of the test conclude?

Basically it's best to study for the MCAT by having a very broad general understanding of the subjects as few questions will reward just straight memorization. Do you need to memorize things? Yes but you still have to apply it and that's the hard part.

What's the best way to learn biochemistry?

Draw out important pathways and cycles. Make rules in your head.

Very informative, thank you.

You need to know about 1/20th of this graph. Look at the structures, fucking look at them until they get burned onto your retinas.

I second this notion

And I'll third it since the thread is getting so close to the bottom.