Brain muscles ..What is the brain? The brain is a complex organ that is part of the Central Nervous System (CNS) and is the most voluminous and known part of the brain. It is located in the anterior and superior part of the cranial cavity and is present in all vertebrates. Inside the skull, the brain floats in a transparent liquid, called cerebrospinal fluid, which fulfills protective functions, both physical and immunological.
Is the brain a muscle? We often hear that the brain must be exercised or if it does not atrophy, like muscles, however we must be clear that the brain is not a muscle . It is not composed of myocytes, muscle cells, but is formed by millions of neurons, which interconnected by axons and dendrites, allow to regulate each and every one of the functions of the body and mind. From breathing, to eating or sleeping, to the ability to reason, to fall in love or to argue with someone, everything goes through the control of the brain.
What is the brain?
What is the brain for? Brain functions
As a fundamental part of the brain and the CNS, the brain could be defined as the one in charge of controlling and regulating most functions of the body and mind . From vital functions such as breathing or heartbeat, through sleep, hunger or thirst to higher functions such as reasoning, memory, attention, control of emotions and behavior …
Everything that happens in our life, in wakefulness and in sleep, whether breathing or swallowing, watching, listening, touching or tasting something, reading or writing, singing or dancing, thinking in silence or talking about our thoughts, loving or hate, walk or run, plan or act spontaneously, imagine or create, etc … To put a list, some of the functions performed by the brain are:
Control of vital functions: Like the control of the temperature, the sanguineous pressure, the cardiac rate, the breathing, to sleep, to eat …
Receive, process, integrate and interpret all the information received from the senses: sight, hearing, taste, touch and smell.
Control the movements we make and the posture position: Walk, run, talk, stand.
It is responsible for our emotions and behaviors .
It allows us to think , reason, feel, be …
Control superior cognitive functions : Memory, learning, perception, executive functions …
“Men should know that the brain is exclusively responsible for joys, pleasures, laughter and fun, and grief, discouragement and lamentation. And thanks to the brain, in a special way, we acquire wisdom and knowledge, and we see, we hear and we know what is disgusting and what is beautiful, what is bad and what is good, what is sweet and what is insipid … And thanks to this organ we go crazy and delirious, and fears and terrors assail us … We must endure all this when the brain is not healthy …
And in this sense I am of the opinion that the viscera exercises in the human being the greatest power ” Hippocrates (s.IV aC) On sacred diseases.
Hipocrátes already sensed it, the human brain is one of the most complex, enigmatic and, at the same time, perfect creations of the universe . In his time, Hippocrates and his contemporaries could not imagine everything we would come to know about the brain. Thanks to technological advances in neuroimaging and in medicine, biology, psychology and neurosciences in general we have been able to decipher great mysteries in terms of anatomy and functioning. However, there are still many unknowns and doubts to be solved.
Parts of the brain
Definition of Brain – What it is and its parts
All vertebrate animals have brains, and this one is made up of the following parts:
The brain , formed by cortical and subcortical structures. The cortical structures or cerebral cortex are divided into different lobes: frontal (A), parietal (B), cingulate (C), occipital (D), temporal and insular (these two are hidden in the image).
In addition, these lobes are divided in half into two hemispheres: the right and the left. The subcortical structures refer to those that remain under the cerebral cortex, such as the corpus callosum (1) that unites the two hemispheres, the thalamus (2), the basal ganglia, amygdala, hippocampusand mamillary bodies (6). The brain is responsible for integrating all the information received by the sensory organs and organizing a response. It controls the motor, emotional functions and all the superior cognitive functions: reasoning, emotional expression, memory, learning …
Cerebellum (10): It is the second largest organ of the brain, and is involved in mainly postural and movement control, although it also performs some cognitive functions.
Hypothalamus (4) and pituitary gland or pituitary gland (5), responsible for visceral functions such as regulation of body temperature and basic behaviors such as diet, sexual response, pleasure seeking, aggressive response …
The Pineal Gland (11): It is the one that is responsible (among other visceral functions) of synchronizing the release of the melatonin hormone and regulating the sleep / wake cycles, for which it is coordinated with the optic chiasm (3).
The brainstem : constituted by the spinal cord (9), the medulla oblongata (8), the protuberance (7) and the mesencephalon. The trunk controls automatic functions such as blood pressure or heartbeat, limbic movements and visceral functions such as digestion or urination.
Characteristics of the human brain
How much does the human brain weigh? What size does it have? How many neurons does the brain have?
In the human brain, the cerebral cortex is one of the most evolved and complex that exists. Not only does it have a larger size than other species, but it also rolls up and folds on itself more often forming convolutions and grooves that give it that characteristic wrinkled appearance.
The human brain has a weight of around 1.4-1-5 kilos and a volume that is around 1130 cc in women and 1260 cc in men.
The brain (and the spinal cord) are covered by membranes, called meninges, which protect it from blows against the skull.
For more protection the brain “floats” in the cerebrospinal fluid.
It is estimated that the human brain is composed of more than 100 billion nerve cells, mostly glial cells and neurons.
THE NEURONS: These are cells specialized in receiving, processing and transmitting information, at the intercellular level as intracellular. They do this by means of electrochemical signals (nerve impulses) called action potential. Structurally, the neurons have the same cytoplasmic elements and the same genetic information as the rest of the cells of the organism.
Neurons are made up of three parts:
Body or soma (6): is the main part of the cell, which contains the nucleus (with DNA), the endoplasmic reticulum and ribosomes (produce proteins) and mitochondria (generate energy). In the soma most metabolic functions of the cell are performed. If the soma dies, the cell dies.
Axons(3): it is a prolongation that leaves the cellular soma, it is a kind of “cable”, in the end of which there are terminal buttons or varicosities (2) that are the synaptic contact points (5), through which transmits the nervous impulse (pre-synaptic element).
The length of axons can vary greatly from neuron to neuron: there are very short (less than 1mm) to longer (more than one meter, which are usually peripheral nerves such as motor neurons). Some axons (especially those of the motor and sensory neurons) are covered by a layer of myelin (4) that speeds up and facilitates the transmission of information. The more myelin the axon contains, the stronger the nervous impulse will come.
Dendrites (1): are nerve endings that come out of the cell soma that branch in the form of a tree. Dendrites are the main component of information reception (postsynaptic element) and are those that enable communication between two neurons.
GLIAL CELLS: They are the most abundant cell type of the CNS. It has the ability to divide in the adult brain (neurogenesis) and its presence is necessary for good brain functioning.
They constitute the main structural support of the neurons, coat their axons with myelin for a better synaptic transmission (Schawann cells), play a role in the nutritional contribution of the cell, participate in the mechanisms of nerve regeneration and repair, in the immunization mechanisms , maintenance of the blood-brain barrier, etc. There are several types of glial cells among them astrocytes, oligodendrocytes and microglia. And in the peripheral nervous system schwann cells, satellites and macrophages:
The gray matter of the brain corresponds mainly to the somas and dendrites of the neurons.
The white matter is the area where axons of neurons predominate. This color is more whitish due to the coating that most of them have of myelin.
How does the brain work?
The brain functions through the transmission of information between neurons (or other receptor or effector cells) by electrical-chemical impulses. This information transmission occurs during the synapse. In the synapse neurons and cells are put in contact and through chemical discharges and electrical impulses are exchanged neurotransmitters that are in charge of exciting or inhibiting the action of the other cell. The terminal buttons of the axons are the pre-synaptic elements of neuronal communication, by means of which the neuron establishes communication with the dendrites, the soma or even another axon.
All this information transmission through the neurons is done in a matter of milliseconds. In a parallel and coordinated way hundreds of connections are produced that allow us to perceive, understand and respond to the world in an appropriate way. We receive thousands of inputs and generate thousands of outputs in a matter of seconds and everything works with the precision of a Swiss watch. We can imagine the brain as a great wiring that connects with the whole body and within the brain itself.