The Brain: Arguably the most essential organ in the human body

What is the brain

The brain is this extremely complex organ that controls every single aspect of your body. Your thoughts, memories, emotions, touch, motor skills, vision, breathing, hunger, and basically everything else that uses a process to regulates your body. Your spinal cord is besties with your brain as they both make up the central nervous system or CNS.

What is the brain made out of?

The brain weighs 3 pounds in the average adult, the brain has 60% of fat. The remaining 40% is a combination of water, protein, carbohydrates, and salts. The brain is not itself a muscle. It contains blood vessels and nerves, including neurons and glial cells.

What is the difference between gray and white matter in the brain?

Gray and white matter are two distinct regions in the central nervous system. In the brain, gray matter is the darker, outer portion. On the other hand, the white matter emphasizes the lighter, inner section of the brain, underneath the gray matter. In the spinal cord this order is actually reversed. The white matter is on the outside, and the gray matter sits within. I know how weird!

Gray matter is mostly made up of neuron somas (the round central cell bodies), and white matter is mostly made of axons (long stems that connects neurons together), wrapped in myelin (a protective coating). The different combination of neuron parts is why the two appear as separate shades on distinct scans.

Each region serves a distinct purpose. Gray matter is responsible for processing and interpreting information, while white matter sends that information to different parts of the nervous system.

How does the brain work?

The brain sends and receives chemical and electrical signals throughout the body. These signals control different processes, and your brain interprets each. Some make you feel tired, some make you feel excited. For example, If you fall on a hard surface your brain sends a signal too feel pain. Some messages are kept within the brain, while others are relayed by the spine and across the body's vast network of nerves. To do this, the central nervous system relies of billions upon billions of neurons (nerve cells).

Main parts of the brain and their functions.

 

At a high level, the brain can be divided into the cerebrum, brainstem, and cerebellum.

Cerebrum

The cerebrum (front of the brain) comprises the gray matter (the cerberal cortex) and white matter resides in the center. The largest part of the brain, the cerebrum initiates and coordinates movement and regulates temperature. Other areas control and enable speech, judgement, thinking, reasoning, problem-solving, emotions, and learning.

Cerebral Cortex

Cortex is Latin for "bark," and describes the outer gray matter covering the cerebrum. The folds of the cortex make it a large surface on the brain. This consists half of the brains structure. The cerebral cortex is also divided into two halves. It is covered with ridges (gyri) and folds (sulci). These two halves join at a large, deep sulcus (the interhemispheric fissure, AKA the medial longitudinal fissure) that runs from the head to the back. The right hemisphere controls the left side of the body and the left hemisphere controls the right side of the body (more about this is mentioned in the other blog post called "The 'left brain' and 'right brain' theory"). These two halves communicate with one another through a C- shaped structure of white matter and nerve pathways called the corpus callosum is in the center of the cerebrum.

 

Brainstem

The brain stem resides in the middle of the brain, it connects the cerebrum with the spinal cord. The brainstem includes the midbrain, the pons, and the medulla.

• Midbrain: The midbrain is a extremely complex structure with a range of different neuron clusters which are nuclei , colliculi, neural pathways and other structures. These features facilitate various functions, from hearing and movement to calculating responses and environmental changes. There is a area in the midbrain called the substantia nigra, this area can be affected if suspected to be diagnosed with Parkinson's disease. This area enables movement and coordination.

• Pons: Pons are the origin for 4 of the 12 cranial nerves. Which enables a range of activities such as tear production, chewing, blinking, focusing vision, balance, hearing, and facial expression. The pons is basically a bridge for the connection of the midbrain and the medulla.

• Medulla: The medulla is located at the bottom of the brain stem where the brain meets the spinal cord, its best friend. The medulla is very significant for survival. Functions of the medulla is mainly regulating many bodily activities, including hear rhythm, blood flow, oxygen, and carbon dioxide levels. The medulla produces reflexive activities such as sneezing, vomiting, coughing, and swallowing.

Spinal Cord

The spinal cords function isn’t so complex but it is definitely an astounding and incredible part of our bodies. This unique part of our body extends from the bottom of the medulla and through a large opening of the skull. The vertebrae's from the spine support the spinal cord. The spinal cord carries messages to the brain and the rest of the body. This can be sending a signal to your hand to pick up a object or a signal to be sad or angry.

Cerebellum

The cerebellum ("little brain") is a fist-sized portion of the brain in the back of the head, below the temporal and occipital lobes and above the brain stem. Similarly, the cerebellum has 2 hemispheres like the cerebral cortex. The outer portion of the hemisphere contains neurons, and the inner are communicated with the cerebral cortex. The cerebellum functions are to coordinate voluntary muscle movements and to maintain posture, balance and equilibrium. There have been recent studies to explore the cerebellum roles in thought, emotions, and social behavior, as well as its possible involvement in bad habits such as addiction.

Brain coverings: Meninges

These 3 layers I am about introduce are protective covering called Meninges that surround the brain and the spinal cord.

• The outer layer, the dura matter, is a thick and tough surface. It includes two layers: the periosteal layer of the dura matter lining with the inner part of the skull which is made of cranium, and the meningeal layer is below that. Spaces between the layers allow for the passage of veins and arteries that supply blood flow to the brain.

• The arachnoid matter is a thin weblike layer of connective tissue that does not contain nerves or blood vessels at all.  Below the arachnoid matter is the cerebrospinal fluid, or CSF. This fluid cushions the entire central nervous system (brain and spinal cord) which also continually circulates around these structures to remove impurities.

• The pia mater is a thin membrane the "hugs" the surface of the brain and follows its contours. The pia mater is rich with veins and arteries.

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 Well as you can see the brain has a lot of anatomical structures that help make this essential and distinct what it is today. The brain is a astonishing organ with its extraordinary facts and functions. This organ represents "great things come in small packages". The brain being a small organ controls every single aspect of our bodies. So next time you think about your brain, remember it's not just processing; it's an electrical, fatty, self-cleaning universe in your head, constantly evolving.