The Human Brain

Not too long ago, I developed an interest in psychology. It really started after I read up on Sigmund Freud and his theories. I have gotten a few books from the library and psychology. I am still in the beginning stages of learning about the human mind. What I want to type about is some of the facts about the human brain that I recently read about.


Fundamentally, there are three parts to the Nervous System. The first part is the Central Nervous System that comprises the brain and the spinal cord. The next part is the Peripheral Nervous System that is made up of twelve cranial nerves and thirty-one spinal cord nerves that sends sensory signals from the receptor points throughout body to the brain (afferent), and sends motor signals from the brain to the body (efferent). So if Sammy (our dog...well, my mother's dog) came in and licked me on my leg or something, the signal from the receptor points from the era that he is licking goes to my brain to interpret or make out the signals, then in reaction, my brain sends motor signals in reaction, and that could be me moving away a certain part of my body that he is licking, shooing him with my hand, or pushing him away slightly. Yep, basically...


Oh shit, I almost forgot about the last  part of the nervous system which is the automatic nervous system. The automatic nervous system controls things without any conscious effort, such as temperature, heat rate, etc.


So there it is, the three fundamental parts of the nervous system.


The thirty-one pairs of spinal cord nerves are allotted to four regions of the body. The first region is the Cervical Region, which has eight pairs of that serve the chest, head, neck, shoulders, arms, and hands. The second area, the Thoracic Region, has twelve pairs of nerves that services the to the back, abdominal and intercostal (whatever that is) muscles. The next area is the Lumbar Region that has five pairs of nerves serving the lower abdomen, thighs, and legs. The last region, the Sacral Region, has six pairs of sacral nerves that connect to legs, feet, anal and genital area (cue dirty look here).


Now for the Cranial Nerves *breathes in deeply... breathes out deeply*. The Cranial nerves serves what it names implies, the carnal or the head. I am going not going to break down everything about the cranial nerves but I will write what each nerve is for. So, here we go...


The first is the Olfactory Nerve for the ear ( 1-sensory), next is the Optic Nerve  for the eyes (2- sensory),  Oculomotor, Trochlear, and Abducens nerves for the eyes (3,4, and 5 - motor), Vestibulacochlear nerve for the ear(6 - sensory), Glosspharyngeal and Hypoglossal nerves for the tongue and swallowing(7 and 8- mixed), Vegus nerve which serves both part of the head and body (9 - mixed), Spinal Accessory nerve for head, neck, and shoulders (10 - mixed), Facial nerves (11 - mixed), and last but not least, Trigeminal nerve for eyes, teetch, face, and jaw (12 - sensory and one mixed branch).


Also, "mixed" means that they are mixed with both motor and senosry nerves, versus soley being a sensory nerve or a motor nerve.


Alright, now on to more facts about the brain...


- The brain makes up about 2% of the overall body weight.


- The size of a person's brain has little to no effect on a person's intelligences because the brain as about he same number of neurons and synapses ( I might get into synapses some other time).


- After about he age of 20, the brain starts to lose 1/52 oz of mass each year. The brain starts to shrink as the neurons starts to die off and not replace itself. Boy, if that doesn't suck. I read that no one should be worried about his because there is still more than enough neurons in a person's brain, but shit, talk about a decline. I'm just saying...


Anyway...


- At birth, the male brain is heavier than the female brain. By the age of 13, however, the female brain is heavier (proof that we're smarter... just kidding).


- A person who does not consume alcohol has more brain volume then a person who doesn't. In other words, a person who does drink experience brain shrinkage. I do remember reading a long time ago that one of the negative effects of drinking is the killing of the brain cells. So, maybe that's why.


- Because of the brain's constant activity, it consumes 20% of the body's glucose to function. It consumes 4oz. of glucose a day.


-The brain does not have a storage supply of glucose so it has to be readily available from the blood supply.


- Without oxygen and glucose, the brain can only survive for 10 minutes before irreparable damage - and even death - ensues.

-The brain is 77-78% water, 8% lipids (fatty molecules), 2% soluble organic substances, 1% carbohoydrates, and 1% inorganic salts.

- The brain is surrounded by Cerebrospinal fluids to absorbs shocks and blows to the brain.

I am going to stop here, but there will be more facts about the human brain that I will be making posts about.