Analysis of the Human Brain The human being is considered to be the ultimate form of life on the earth. This is not because the human body is strong and agile. Many other animals posses skills much superior to humans and are able to perform feats humans can only dream of. The one thing that distinguishes humans from all of the other organisms on this planet is the brain.
The brain is the site that controls the human body. However, unlike in animals, in man, the brain is also the site of the mind. The mind gives humans superiority over other creatures. It provides humans with the ability to reason, to feel and to adapt. Because of this, man has achieved so much, and has also realized that much more is still ahead.
During the course of evolution, ever since early man and his ancestors walked on the surface of the earth, man has wondered about himself, and how he relates to the natural world. People learned and adapted to new lifestyles. As time passed, humans learned to record history. They analyzed past events and applied this knowledge to solve problems. These processes improved as more and more people supplied their experiences to the common pool of knowledge.
Such co-operation created the modern man with his ability to think. Many studies were started. Some of them centered around humans. They included, among many others, psychology and neurology. While psychology deals with the mind and human behavior, neurology is the study of the nervous system. The nervous system of the human being consists of several parts. The main structures are the brain and the spinal chord.
The system also includes nerves which sense external and internal stimuli and then relate all information to the central processing unit, i. Because of man's rapid evolution in technology and medicine, humans now know a great deal more about their own nervous system then they did even a few years ago. This increase in knowledge is partly due to the recent advances in nuclear medicine. The space between duramater and arachnoid is the subdural space and the space between arachnoid and piamater is known as subarachnoid space Fig.
These spaces surrounding the brain as well as the cavities within the brain are filled with a lymphatic fluid, called cerebrospinal fluid CSF. The cerebrospinal fluid is also present within the spinal cord. The cerebrospinal fluid protects the central nervous system from external shock; helps in exchange of nutrients and waste products between the nervous tissue and blood and maintains a constant pressure in and around the brain. The brain is formed of two types of nervous tissue, Grey matter on the outer side and White matter on the inner side.
The former is made of non-medullated nerve cells whereas the latter is formed of medullated nerve cells. The brain or encephalon is a white, bilaterally symmetrical structure.
The anterior most part of the fore brain is a pair of olfactory lobes. They consist of an anterior club shaped olfactory bulb and posterior olfactory tract. The cavity of the olfactory lobes or rhinocoel is not well marked. The olfactory lobes are the centers of smell. The cerebral hemispheres or cerebrum is the largest part of the brain occupying about two-third of the entire brain.
It is divided into right and left cerebral hemispheres by a deep longitudinal median groove Fig. These two cerebral hemispheres are connected by a transverse sheet of nerve fibres, called corpus callosum Fig. The anterior part of corpus callosum is bent slightly downward to form genu while the posterior part is raised upward to form splenium.
The cerebral hemispheres are divided by 3 deep fissures into 4 lobes viz. The parietal lobe or the somaestic area is the centre for the perceptions of sensations like pain, touch and temperature. The occipital lobe has two areas viz. On the ventral side there is a longitudinal fissure called rhinal fissure which separates the hippocampal lobe or pyriform lobe from anterior lobe in each cerebral hemisphere.
Insula or Island of Reil is a small lobe of cerebrum, covered over by parietal frontal, and temporal lobes. It co-ordinates the action of different regions of cerebral hemispheres. The outer layer of cerebral hemispheres is called cerebral cortex or neopallium. It is formed of grey matter and contains millions of neurons. Grey matter also forms islands on the white matter. These are called cerebral nuclei. The cerebral cortex is highly convulated in order to increase its surface area.
The ridges of these convultions are called gyri and depressions between them as sulci. The cavities within the cerebral hemispheres are called lateral ventricles First and second ventricles which open to third ventricle cavity of diencephalon by a foramen of Monro Fig.
The centres of reception of these are located in the sensory areas called soma esthetic area present in the parietal lobe. It is the last part of the forebrain and is almost covered dorsally by cerebral hemispheres. On its dorsal surface it bears a pineal stalk with a rounded pineal body at its top.
The dorsal vascular wall forms anterior choroid plexus. Its cavity is called diocoel or third ventricle. On the ventral side hypothalamus forms the floor of the diocoel. It consists of number of scattered masses of the grey matter in the white matter. The pituitary hangs below the hypothalamus by a stalk called infundibulum. Below pituitary is mammillary body. Two optic nerves cross each other to form optic chiasma in front of the pituitary Fig.
Diencephalon regulates manifestations of emotions and recognizes sensations like heat, cold and pain. Hypothalamus contains nerve centres for temperature regulations, hunger, thirst and emotions. It also produces various neurohormones that control the secretions of anterior pituitary.
The limbic system, often called the "emotional brain", occurs deep within the cerebrum and is evolutionary old, like the cerebellum. This system is composed of the thalamus, amygdale, the hypothalamus, and hippocampus. The following is a midsagittal view of the human brain showing the limbic system: (Ford, ).
An adult human brain weighs about gms. (In a new born baby it is about gms and becomes double after one year) and has a volume of about c.c. It is enclosed in a bony case called cranium which protects brain against external injury. (a) Meninges. The brain is being surrounded by three membranes called meninges (sing-meninx).
The Human Brain Essay Words | 5 Pages. The human brain is a big, intricate—yet delicate, structure in the human body. It is the key structure in cognitive function. Any damage to the brain does not only “erase” memories but also may “deceive” the brain to erroneously remember a new object as being familiar (). The Human Brain Essay - The human brain is a vital part of life; however, many do not understand the significance of this complex organ. The human brain is like other parts of the body; it grows, gets stronger, weakens and dies.
Without blood, the human body would not be able to perform several of its normal functions. In fact, blood can be said to perform functions that are relevant to the cells, the heart, the brain and the organs. The Human Brain Essay INTRODUCTION The human body is divided into many different parts called organs. All of the parts are controlled .