Have you ever wondered how the brain works? How we, as such an amazingly complex species are able to function?
Well – the answer to this is through the running of our nervous system. In this blog, we will be exploring the seemingly simple phenomenon that allows us to run our highly complex structures today.
Underlying Concepts
Behind the running of our nervous system (as well as our other body structures), there is two underlying principles – homeostasis and negative feedback. Homeostasis is the constant internal environment that our body works to maintain through “negative feedback” loops – where a sensor detects an imbalance, signals a control center, and activates an effector that reverses or stabilizes, making the body regain its balance.
The Neuron
The cells of the nervous system are called neurons and they work to conduct nerve impulses. Their structure is based on having dendrites that collect nerve impulses from the sensors in the body and send an action potential or electrical impulse along the axon to the central nervous system when in any imbalance. The central nervous system, composed of the brain and the spinal cord, decides how to react or how our body’s response would be.
The most fascinating part of the nervous system cells or neurons is how they are able to transfer this electrical impulse to the central parts. Well – this is through a relatively simple yet beautiful way by sodium potassium pumps.
- The plasma membrane of almost all cells has an electrical potential of -70mV (resting potential). When a nerve cells recieves any stimulus, it becomes permeable to more sodium ions which enter and cause a reversal of charge called depolarization (the cell membrane has a potential of 40mV). The flow of postively charged ions toward the adjacent resting areas causes an electrical distrubance, that triggers a wave of depolarization along the membrane.
- Neurotransmitters at the end of the nerve cells and receptors at the start of the next nerve cell allow the transfer of this action potential or impulse along multiple neurons until it reaches the central nervous system.
One very cool fact about the central nervous system is our reflexes – our involuntary actions that protect us from stimulus in the environment. Within reflexes, the neurons convey the message to the spinal cord before the brain – so we often react before we even interpret what is happening. This is why we move back our hands when we touch the stove, even before we scream or realize the pain!
The Central Nervous System
Now, we come to the brain and the spinal cord- the two fundamental operating sectors of the body, which compose the central nervous system.
The spinal cord is responsible for co-ordinating the body in its response. In the case of reflexes, it contains interneurons that connect sensory neurons to motor neurons in order to generate a fast response. It also carries this information to the brain for intrepretation. Emerging from the skull, the spinal cord extends through the backbone, with nerve tissues called white matter and grey matter. It is protected by the vertebral column (bones that encases it and protects it from any damage).
The brain comprises of three regions: the forebrain, the midbrain, and the hindbrain. Each hemisphere is composed of different lobes, with futher components of each lobe into distinct parts. There is incredible detail into the anatomy of the brain and the several complex structures that you can find in this website. The cerebrum controls movement and regulates internal temperature, in addition to several other functions such handling the senses, or emotions. The brain stem connects the cerebrum with the spinal cord in order to encompass the central nervous system. On the whole, the brain in composed of 60% fat containing blood vessels, nerves, and neurons, encased by the cranum built to protect it. One fun fact is that there is an estimated number of approx. 100 billion neurons in a fully mature human brain.
TL;DR
On the whole, the brain and the spinal cord are incredibly important structures that allow us to be human – give us the ability to think, feel, and experience emotions as we do as homo sapiens. Learning and understanding information about the brain can help us understand and appreciate the incredible complexity of the body that we have. Always remember, “ignorance is bliss, but knowledge is power.” The more you know.
