This Is Your Nervous System
Your personal electrical grid and why your health depends on it.
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Hello!
Welcome to Basics Matter, a 6-month series where we will explore one human system per month. We will dive into how the human body works, how you can better understand it and take good care of it. This will allow you gain control of how you feel and prevent disease in the future.
Why am I teaching the basics?
Let me share a story: I always tell my patients that we are a team. They always seem surprised when I say this, but then I proceed to explain: “You live in a human body. I have studied it from the books, but you have lived in yours all your life. Only you know what you feel, and it’s my job to listen to you and try to translate what you feel into a diagnose that makes sense, if any. It’s team work!” As a doctor, I want you to know your body, to understand what it is doing and telling you. No, you don’t need a medical degree. All I want is for you to become aware of it.
That’s what this series is for. To help you understand your incredible human nature. To help you learn the language of your body. And to empower you into taking better control of your health—before it turns into disease. By learning the human body basics, you’re becoming aware…and awareness is everything. It’s the first step towards change, including health. This is the way to prevention, my friends. And we’re all here for it. Now more than ever.
Today we dive into the very first system! Let’s begin.
As I mentioned in our introductory email, in 2025 we are diving into six of the main human body systems—specifically: nervous, cardiovascular, respiratory, digestive, endocrine, and musculoskeletal systems.
In case you missed it, I highly recommend you have a quick read of the intro so you can settle the foundations before continuing here. Don’t worry, go ahead and read it. I’ll wait for you.
Cool, have you read it?
Perfect! Let’s dig in.
In today’s newsletter you will learn:
What is the Nervous System?
What parts make up the Nervous System?
How does the Nervous System works?
How do neurons (and cells in general) communicate with each other?
Like with any big thing, call it a project, an event, or even a flight, there is always a certain person or collective in charge, making sure that the thing has a solid foundation and runs smoothly from beginning to end.
In the human body’s case it is no different. Like you know, there are many organs and systems in the body doing different and specific functions. While doing that they also communicate with each other. It’s a vast machinery that works pretty much on its own, but of course there’s a system in charge of it all–or as some would call it: a control tower.
Say hello to the Nervous System!
Your command centre. Let’s cover its most important basics.
The nervous system is the human body system in charge of controlling, organising, coordinating, and leading every function in the body. It’s made up of three parts: your brain, your spinal cord, and a vast network of nerves. It’s not located just in one place but more like all over the place, like this:
According to their location, the nervous system is divided in two parts: central nervous system and peripheral nervous system. By central we refer to the brain and the spinal cord, while the nerves comprise the peripheral side of it. Like this:
Now, remember I told you in the introductory email that the human body is made of four main structures? Cells, tissues, organs and systems. And that cells become specialised early on into specific functions that will make up a tissue, that will make up an organ?
The nervous system’s cells are called Neurons, and they have a lovely, funny look like this (reminds me of a scorpion):
Basically, your nervous system is a complex electrical network within your body that controls all of its functions. If you’ve read me for a while, you know I love a good source, and Cleveland Clinic is one I always refer to. Here’s their good explanation of what the nervous system does:
“Your nervous system works by sending messages, or electrical signals, between your brain and all the other parts of your body. These signals tell you to breathe, move, speak and see, for example. Your nervous system keeps track of what’s going on inside and outside of your body and decides how to respond to any situation you’re in.
…it regulates complicated processes like thoughts and memory. It also plays an essential role in the things your body does without thinking, like blushing, sweating and blinking.”
This system might seem complex to start with, but the beauty of it is that by understanding the control tower of your body, you will then easily see how all of the other systems and their unique organs work and connect to keep you healthy. This is why we are doing the nervous system first.
I’m a massive geek of the human body, always amazed by it and by everything we are constantly discovering, its abilities and capacities to perform, to heal, to break down and build up again—all on its own. This always gets me thinking… We are so used to seeing other humans on a daily basis, interacting and such, but have you really put some deeper thought into how your body keeps you safe, sane and alive most of the time without you even thinking much about it?
Let’s think about it.
Throughout any common day, you eat, drink, sleep, walk, pee, and poop without putting a great effort into it. You just know that certain things need to be done in order to function and have energy for work, the kids, exercise. If you’re lucky enough, you’re doing all this most likely on auto-mode while having all sorts of thoughts, emotions and reactions in your head. Am I right? And guess who’s running the show in the background while you drive and think about picking up the kids, or about the appointment you need to go to, or that other meeting you must reschedule?
That’s right…the marvellous Nervous System.
It controls not just your physical functions but also your emotional ones. A huge part of how your emotions and thought processes work is thanks to some amazing parts and substances in your brain. We will look into this in detail ahead.
For now, let’s focus on the physical side of things.
As mentioned, the nervous system is made of three parts: the brain, the spinal cord, and the nerves. Let’s start with the brain.
The Brain
The brain is the organ located right inside your head, or better said, inside your skull–that hard, round ball above your neck and shoulders—the one that’s so difficult to crack open, and the one that you can turn side to side when talking to people, looking around or simply stretching.
The brain is made of two halves called hemispheres, which connect via a structure called Corpus Callosum. A smaller structure sits on the back of the brain called Cerebellum. The brain is divided in four regions called lobes, and these are: frontal, parietal, temporal and occipital lobes. Each lobe holds different structures within them, all in charge of a massive diversity of functions, ranging from sight, smell, memories, movement, emotions, balance, hearing, and involuntary functions such as heart-beating, breathing, sweating, and more. All of these have a signal originating in the brain. It’s crazy cool!
Here’s an image of the brain from different angles:
To make it easier for you to visualise, here’s a cute brain with glasses so you can see where’s the front side:
And if you’re open to it, here’s a real human brain shown by a scientist who explains a few amazing facts:
Like I said, the brain is protected by the skull.
Skull is indeed the name for the head’s bone, smartly created to protect the one organ that holds the most vital functions as well as the most mysteries in human life.
The skull is quite an interesting bone. It’s not one single piece of bone but a few sections of them that are flexible from birth until approximately 2 years of age, when they fuse together making the round head as we know it. When you look at a plain skull, you’ll see some lines or divisions (we call them sutures) and they are incredibly important during those developmental years.
In the first years of life, everything inside of us is continually growing and expanding. Imagine if the skull were a hard, tight, rigid bone from the start, then a baby’s head wouldn’t be able to mould through the mother’s vaginal canal during birth. It could also happen that the brain wouldn't have enough room to grow as we grow. Sometimes, when this happens, we have a situation called Craniosynostosis, a birth defect where one or more sutures fuse prematurely, causing a misshapen head appearance, and potentially affecting the brain’s growth. In most cases is detected at birth or early on, and even though it might involve some corrective surgeries, most babies with this condition will have a normal cognitive brain development.
Under normal biological circumstances, these sutures will stay open and finally fuse around 2 years of age, time when the flexible skull material becomes stronger giving way to a proper bone structure that will hold the brain forever.
Now, even though the skull is hard and somehow round, the brain is quite the opposite: squishy and slightly elongated. When you manipulate an actual human brain (as shown in the video), its surface and sensations are quite unimaginable. Soft but slightly elastic, smooth, squishy, delicate and strong at the same time. Seriously, the brain is so unique.
Cool, right? Let’s move onto the next part.
The Spinal Cord
Going down from the brain, we find the spinal cord, a thin but vital structure that runs from the base of your neck down to the base of your back, almost into your crack.
This thin structure is an absolute wonder of nature. It’s a cylinder-shaped tube of nervous tissue (collective of nerve cells or neurons) that carries messages from your brain to the rest of your body.
Basically, the spinal cord works as a bridge between nerves (peripheral nervous system) and the brain. It is what allows all information and electric impulses to travel from one end to the other, giving us the ability to perform all sorts of functions, like walking, talking, eating, moving our arms or legs, or doing detailed hand and finger movements, just to mention a few examples.
Here’s a real human brain with its spinal cord up close, along with some more mind-blowing facts:
When the spinal cord is injured or damaged, it could give us serious consequences, affecting our ability to talk or walk. In more serious cases it could even affect our ability to breathe.
The spinal cord is as important as the brain. In the same way that the brain is protected by the skull, the spinal cord is protected by smaller, circular bones called vertebrae. We have 33 vertebrae, each one of them separated by a tiny collagen disc in between to allow them some cushioning and to avoid friction. They all form an incredibly protective canal right in the middle, where the spinal cord runs through.
Here’s one typical lumbar vertebra:
As we become adults, the last 5-6 vertebrae become merged into a single structure (the sacral-coxis bone). This chain of 33 vertebrae with its merged end and the collagen discs is what we call the Backbone or Spine.
Each of these bones have tiny canals on the sides, where long fibres of neurons leave the spinal cord and extend throughout the rest of the body, carrying all signals and commands to and from the brain. These long fibres of nervous tissue are what we call the nerves. Let’s talk about them next.
The Nerves
Masters of the peripheral nervous system.
The nerves are bundles of neurons or nerve cells, that carry the electric signals between the brain and the rest of your body. In other words, nerves are the electric cable network of the human body. They are identified according to a vertebrae number, and they all have specific functions according to their location and the pathway they run.
In this electric network, nerves transport signals of all kinds, both from inside and outside of our bodies. It is thanks to the nerves and their specific terminations that we can feel things such as temperature on our skin, a feverish sensation within the body, pain when we get kicked, or pain from an inflamed organ, like menstrual cramps or digestive aches.
You know when you touch a hot pot and instantly remove your hand/arm in a flash? This super automatic response happens in fractions of a second before you even know it. The temperature nerve endings (sensors) on your skin detect a threat and send an immediate signal to your brain saying: “Hey brain! High temperature detected in this section, with high risk of burn ahead. Please remove!” To which the brain responds with a fast muscle signal making you move your hand/arm away from the threat.
Fascinating! Don’t you think?
We have 12 main nerves that start their journey right in the brain (called cranial nerves), and then we have the spinal nerves which originate in the spinal cord and run outside of the backbone into the rest of your body.
Let me blow your mind one second here. The cranial nerves (along with their unique functions) are these:
Fun fact: did you know that the tongue is all muscle and no bone? It is made exactly of eight muscles, and together, they can perform activities that require massive strength. It has been believed that the tongue is the strongest muscle in the body, but this has been a debunked myth, according to Scientific American.
As you can see, the nervous system is indeed the master control tower of everything that the human body can do, whether you realise it or not.
“In other words, nerves are involved in everything you do, think and feel. Your nerve cells send and receive information from all body sources. This constant feedback is essential to your body’s optimal function.” ~ Cleveland Clinic
That’s why learning about your nervous system first is key to everything we will learn after this.
Now, knowing what the nervous system looks like and how it works, I want to show you how the nervous system talk with the other systems.
Let’s Talk About How Cells Talk To Each Other
All cells in the body, regardless of their type and location (near or far), communicate with each other. The way they communicate is through a messaging system, using particles called Ligands, that travel between cells when they’re nearby, or through the bloodstream when the message is to be delivered far away. Like this:
This process is called cellular communication:
“Cellular communication is a complex process involving various biochemical steps and many different messenger molecules between cells and organs.[1] Cells in the human body are highly specialized, and they use various signaling mechanisms to perform different functions.” ~ National Library of Medicine
“Cell–cell communication (CCC) is essential for growth, development, differentiation, tissue and organ formation, maintenance, and physiological regulation. Cells communicate through direct contact or at a distance using ligand–receptor interactions.” ~ Signal Transduction & Targeted Therapy Magazine
Without cellular communication, nothing in the body would work. Maybe this gives you a powerful overview on why studying cells is a basic theme in all school programs.
Now, in the case of the nervous system, the ligands are called neurotransmitters.
As Cleveland Clinic explains:
“Neurotransmitters are chemical messengers that your body can’t function without. Their job is to carry chemical signals (“messages”) from one neuron (nerve cell) to the next target cell. The next target cell can be another nerve cell, a muscle cell or a gland.”
Neurotransmitters are usually produced and stored in vesicle sacks on one end of every nerve cell. We have thousands of nerve cells, and each one of them can store thousands of neurotransmitters in one sack alone. They are stored in these sacks inside the nerve cell until a signal is received, releasing them outside of the nerve cell, ready to travel where they’re needed.
When the neurotransmitter reaches the target cell, it binds to a specific port called receptor, unlocking an action by this target cell, actions such as moving a muscle or releasing a hormone into the bloodstream. After neurotransmitters have delivered its message, they are either reabsorbed by the cells or broken down into other usable parts. The body is not only smart but sustainable too!
Here’s what two neurons communicating look like:
A signal is received by Neuron 1 to release a specific neurotransmitter. The vesicles get ready, they approach the cell’s wall to open the doors and let NT out into the space in between cells. While here, they find their specific port in Neuron 2 where they will bind, allowing the cell to receive the message and perform the needed action.
Some well-known neurotransmitters that you might have heard of are: dopamine, serotonin (the happy hormone), endorphins, and adrenaline. They can influence everything from mood to focus, energy levels, learning, sleep, and appetite.
“Neurotransmitters play a critical role in neural communication, influencing everything from involuntary movements to learning to mood. This system is both complex and highly interconnected. Neurotransmitters act in specific ways, but they can also be affected by diseases, drugs, or even the actions of other chemical messengers.” ~ Very Well Mind
In short, neurotransmitters are the language of the nervous system.
It’s how nerve cells communicate in order to send messages throughout the body, allowing it to function normally at all times. That’s how it goes 24/7/365.
The body is a machine of constant chemical reactions working together to keep you in balance. It never rests, it never stops, sometimes it has mishaps or fails here and there. That’s when disease happens, and that’s when we must chime in to see what’s going on and help it recover as soon as possible.
It’s all fascinating! I really hope you’re getting the general picture, and the same hype, excitement and understanding as I am while sharing all this knowledge with you.
Let’s Summarise
Here are the main bullet points of what we’ve covered today, so that you can easily refer to them anytime you need:
The Nervous System (NS) is the system of the human body in charge of controlling, organising and leading every single function of every single cell and organ in the body.
The NS is formed by three main structures: the brain, the spinal cord, and the nerves. Brain and spinal cord make the central nervous system, and the nerves make the peripheral nervous system.
The cell of the nervous system is called a Neuron. They talk to each other via chemical communication.
The NS works as a complex electric network that allows every cell to communicate with each other, whether near or far, so that messages of what’s needed or needs to be done can travel throughout the body.
The NS is involved not only in all physical activities but also with emotions, feelings, reasoning and thought processes. It all connects and the NS is in charge of coordinating everything.
The NS has its own communication system, via particles or messengers called neurotransmitters. They’re produced in every neuron and they’re vital to the entire body’s functioning.
And we’re done for today!
It’s a good lot to learn and process. We’re here to learn through fun, mind-blowing, nerdy facts about our incredible nature. So please, take your time and enjoy!
Next time we will dive into Part 2 of the Nervous System. We will talk about what happens when the nervous system gets sick, what can you do to take good care of it, and how to prevent future ailments as possible.
Stay tuned!
Much love,
Dr. Mariana
Do you have doubts? I’m sure you do! Throw them in the comments below and I’ll clear them as best as possible so that everyone can learn from it too.
I am reveling in this material and your captivating presentation—especially the diagrams. I’ve chosen a different approach to MD (Mind Doctor); I recently returned to society after over 5 years as a Buddhist Monk. Reading this while being guided by your enthusiastic voice brought back my interest in the traditional Medical field. I haven’t found a doctor like you yet, so I maintain my optimal health by living a mostly plant-based lifestyle, practicing mindful living, and incorporating breathwork throughout the day. You truly inspire me! I have a new Doctor and NP but I know enough to make their job easy for me 😉. I have excellent health!
Keep shining like a 💎
Bravo. You’ve raised the bar for MDs! 👏🏾😎