Brain is the supreme master of our body. What our brain does, any other organ cannot even do the inch of it. It is like a King, which controls his kingdom very well.
But, again, it is in our body. A mass of cells can be so capable, we never knew! The more we learn about brain, the more we are driven to know its deepest secrets. Let us know more about what a brain “anatomy” means!
What is brain anatomy?
A brain is the main part of the Central Nervous System. What it does, we all are aware of it. Anatomy refers to the internal study of something and its functions as well.
The brain looks like a walnut. Kept safe inside the skull protection, it has a coiled appearance, and is soft to touch. It is all wet and moist, and if you get a chance to touch a human brain, you are definitely going to get a chilly feeling.
If you know much about the external structure of the brain, then you are at the correct place to learn more about the anatomy.
The human brain looks simply coiled and fluidic from the external view. But, as you must know, the brain consists of billions of neurons and their dense network.
How these neurons are interconnected? How does the brain looks from inside? The working of brain is so wide, then how does it functions as a single unit? And many more such questions must be banging in your head.
Let us learn together something more about the human brain!
Human brain anatomy, functions and physiology
A human brain is very complex and puzzling! It has 3 main parts, out of which the cerebrum is the largest part.
The three parts of brain are:
- Brain stem
This cerebrum is divided into 4 lobes according to the specific regions.
- Frontal Lobe
- Parietal lobe
- Occipital lobe
- Temporal lobe
All these lobes can be easily identified in the following image:
Are you thinking about what are the functions of these lobes?
The Frontal Lobe controls the motor movement, speech and its orientation and your emotions. Emotions are the result of hormonal events occurring in your body.
So, it can be said that frontal lobe monitors your hormonal changes as well. It also controls your reasoning power and the way you solve your problems.
The parietal lobe controls your power of recognition and the stimulus. It is the one which is responsible for your perception. It also defines the range of movement.
The occipital lobe manages what you see and what you imagine. It is responsible for the way how you visualise the world.
The temporal lobe is the lower one. It is situated at the base. It holds the deepest secrets of your life and remembers everything that happens with you! It is responsible for memory storage and also recognises the auditory stimuli.
What is an auditory stimulus? It is the whole hearing system of yours. The ear, the power to listen and the ability to react to such responses, it all comes under the auditory system!
Now, we have discussed about the lobes of cerebrum. But, apart from the division into lobes, what exactly is the cerebrum? Can you see the diagram above? Can you see the cerebrum?
The CORTEX is the cerebrum. It is the largest portion of the brain, and is compactly composed. It is highly coiled, right? Can you wonder why? The layer of the cortex is folded many times, making a wrinkled surface.
This is done so in order to increase the surface area, so that more neurons can be accommodated and brain can be built stronger. The degree of folding comes under “gyrencephalisation”. Sounds very dangerous, no? It does to me at least!
The cerebrum is divided into two halves with a longitudinal suture: left hemisphere and right hemisphere. These are equal in size, but have distinct functions.
The right hemisphere is the creative head and the left hemisphere is the smart and logical head. These two hemispheres are linked to each other by a set of axons known as corpus callosum. Do you know what an axon is?
The folding is initially composed of gray matter. Beneath, there are numerous nerve fibres and cells which form the entire system. The major upper portion, that is the cortex, is also called neo cortex. It is said to be a modified brain region.
Now let us talk a little about the cerebellum. Beneath the cerebrum is the cerebellum. It exhibits more degree of coiling than the cerebrum. It is also divided into two hemispheres, and is responsible for the movement.
It also maintains the aligned posture and balance of the body.
You will be amused to know that, the cerebellum has been found (on evolutionary basis) to have been present in other mammals as well. But, what we have as the “neo-cortex” has not been found in mammals.
This means, we are the first ones to have the neo-cortex, which is the advanced form of cortex.
There are some parts hidden as well! Under the cerebrum, the thalamus, hypothalamus, amygdale and hippocampus are present. These are one of the crucial parts of the brain!
- Hippocampus: regulates memory, whether short term or permanent.
- Hypothalamus: regulates the master gland, the pituitary gland and much more
- Amygdale: these are two almond-like masses. They are composed of several neurons.
- Thalamus: it relays signals and regulates motor control.
The brain stem is an integral part of brain. The respiration process, heartbeats and blood pressure is controlled by this part only. It is composed of three sections: midbrain, Pons and medulla.
3D Brain anatomy
3D brain structure is the best to study the anatomy. Such 3D visuals are widely available on the internet. You can search them out and explore the brain anatomy yourself. Rotate the structure in any way you want and study it yourself.
Brain anatomy diagram
Brain anatomy model
Not everyone has an approach to internet, and not everyone can understand the things online. Until and unless we explore things ourselves, we do not learn. To ease out this issue, various self explanatory anatomy models are available in the market.
Brain surface anatomy
We have learnt about the parts of the brain. Now, let us focus on the important section of our brain! The surface!
The surface is intensely folded, with the outer folding called gyrus and the inner folding called sulcus. They have a functional control. The cerebrum is round in shape, and the coiled structure can be easily visualised. And, we already know that the hemispheres are connected to each other with the corpus callosum.
How is the surface studied? With the MRI (Magnetic Imaging Resonance) technique. This technique shows excellent view of the wrinkled surface.
The surface of the hemispheres is composed of six layers. The degree of thickness varies. The gray matter is constrained by the white matter. Beneath the outer layer are the several neurons connected to each other and forming a dense network. The axons are the connecting links.
There have been several myths about the gray and white matter of the brain and the studies are still going on in order to reveal the truth.
Brain ventricle anatomy
The first question arises is what is the ventricle? There are some spaces present in the brain, which can also be termed as the cavities. These spaces are filled with fluid. Now you know why the brain feels so wet when squeezed? And also, major portion of the brain is water.
There are four ventricles in total.
- The two ventricles are situated in the hemisphere region. They are termed as the lateral hemispheres.
- There is a ventricle between the thalamus and the hypothalamus. It is situated at the centre.
- Another of the ventricle lies between the cerebellum and the brain stem.
The cerebrospinal fluid (CSF) is filled in these ventricles, which are connected to each other by the tubes. The CSF flows from one ventricle to the other through these tubes and also in the spaces between the layers.
Anatomy and functional areas of brain
Brain functions as a single unit, but it has components within itself. Each part does its own work very efficiently and accordingly.
Here are the functions in brief:
- Frontal lobe: emotional and intellectual ability, memory, usual behaviour, reasoning and ability to solve problems, planning
- Parietal lobe: sensitivity to reflexes, orientation
- Occipital lobe: visual ability
- Temporal lobe: hearing ability and memory
- Cerebellum: posture and alignment of the body, stimulus and reflexes, complex actions and sensory information
- Brain stem: breathing, blood pressure, heart beat and heart rate, hunger and thirst
- Cranial nerves: movement of the eye, facial expression control, tasting ability and swallowing
- Cerebrospinal fluid (CSF): protects brain and the spinal cord, nutrient transportation, removal of waste material
- Meninges: protective layers
- Corpus callosum: connects left hemisphere and right hemisphere together, and allows communication
- Thalamus: relaying of signals to and fro
- Hypothalamus: controls body temperature, hormonal levels, metabolism, reproduction, appetite
- Pituitary gland: hormone production
- Endocrine system: hormones regulation which in turn controls the growth and sleep patterns, and other activities
- Ventricles: fluid holding capacity, keeps brain hydrated
- Pineal gland: hormonal balance
- Choroid plexus: production of CSF
- And there are several other components we are missing out. Each fulfils its own duty!
Anatomy of brain and spinal cord
The brain and spinal cord form the crucial CNS. They are connected through the brain stem to each other. The spinal cord runs all the way from brain stem to the tail bone. Move a finger across your back. You can feel the hard bone running down. This spinal cord gives you the basic structure.
The brain and spinal cord junction is protected by the skull. And, if we talk about the muscles, then meninges cover these two. They give a firm protection. Each layer has its own function. The fluid which runs in the ventricles and in between the meninges is the cerebrospinal fluid. This works as the cushion to brain and the spinal cord. The circulation of the fluid goes on and on.
Just like the brain, the spinal cord is covered by three membranes: Dura mater, arachnoid and pia mater. Also, it can be said to have 4 parts:
- Cervical: it is the upper region
One key point is that the gray matter is surrounded by white matter at the circumference region only.
We are just learning the relation of the brain with the spinal cord; hence let us not go deeper.
Brain layers anatomy
The layers of the brain we have been reading about since beginning are the “meninges”. They are the membranes or layers which make the brain surface.
- Dura mater
- Pia mater
These layers are responsible to provide the structure of the brain. The basic framework is composed of these layers only. They have cerebrospinal fluid running in between, which lowers down the friction between these layers and protects them from any sort of damage.
- Dura mater: first of all, it is the outermost layer. This lies beneath the bones of skull and the vertebral column. It is further composed of two sub layers- the endosteal layer and the meningeal layer. The anatomy is always the tough part to understand, so it is completely fine to take time to catch up with the things.
- Arachnoid mater: it is the middle layer. Connective tissues form this layer. There is a space beneath this layer called sub-arachnoid space, which is filled with the CSF.
- Pia mater: it is below the arachnoid layer. Thin and fixed to the brain surface as well as the spinal cord, it is highly vascularised. It means it is well intertwined with the blood vessels.
We haven’t explained much deeply. But, there are several other important parts which are complex and have their own role!
Brain lobe anatomy
The lobes are the important regions! Know more about them here:
- As you know that the lobes are composed of the gray matter as well as the white matter. The gray matter is said to have the cell bodies, whereas the white matter is said to have axon dominancy.
- The density of the white matter is low, and that of gray matter is high.
- The lobes are separated by sulcus and gyrus divisions.
- The frontal lobe occupies the largest area.
- The other lobes are comparatively in shorter area.
- Anterior cranial fossae are the anterior parts of the frontal lobe.
- Middle cranial fossae are of temporal lobe.
- Posterior fossae are of cerebellum and the brain stem.
Brain sulcus gyrus anatomy
- Sulcus is the depression of the surface, whereas the ridge is the gyrus. You can imagine these as a form of wave! Remember the trough and crest concept?
- There is a deep main sulcus, the corpus callosum one, which divides the cortex in two hemispheres. This is called the inter-hemispheric fissure.
- Another such fissure is the Sylvain fissure. It separates the temporal lobe from the parietal and the frontal one.
- Parieto-occipital fissure is a deep fissure. It makes a Y shape and X shape when observed from different viewpoints.
- Collateral sulcus divides the fusiform gyrus and the parahippocampal gyri.
- Parietal lobe and frontal lobes are separated by the central sulcus.
This is just a little of the information we shared with you! There is a lot to explore, and as you learn more, the more unusual terms you shall discover. That’s the challenge! Enjoy learning about the brain!