Human Brain Structure

Human Brain Real

Human Brain is a physical thing, defined as a structure that contains billions of cells and weighs about tree pound. Human brain is like one of the most powerful and sophisticated computers in world. It seems a pinkish jelly like mass that uses very little energy and operates mainly in sugar. Its 100 billion cells can process and store enough information to fill 20 million books, and retrieve much of this information in a millionth of a second.

It is true that computers are being developed with larger and larger memories and programs that can perform increasingly difficult tasks. But no machine can match the human brain’s ability to comprehend a dozen spoken languages and to make jokes in each one. Knowledge Galaxy is the best platform for best guide the information about the health anther field of like health, and beauty.

Brain consists of three basic human brain parts, each with subdivision.

1. Fore Brain
2. Mid Brain
3. Hind Brain

The Human Brain Diagram

Forebrain Parts and Functions

Fore brain includes diencephalon, the limbic system, the two halves of cerebral hemisphere and the outer most covering, the cortex. It has following parts

1. Cerebral Cortex
2. Hemispheres
3. Corpus Collosum
4. Lobes
5. Areas of cortex
6. Thalamus
7. Basal Ganglia
8. Hypothalamus
9. Limbic System

CEREBRAL CORTEX

Cortex means outer bark or covering. The cerebral cortex is also called cerebrum.  It is our Centre for processing and shoring information about the world in which we live, and it also the starting place for virtually all of our voluntary action.

The CEREBRAL CORTEX is significantly larger than any other brain structure. It is the complex, delicate development of the highest region of the forebrain and is the most recently developed part of the brain in the evolution scheme.

Planning and Thinking take place here as they are highest mental functions. It covers the lower portion of the brain like a larger cap.

In humans, the cerebral cortex is greatly convoluted with lots of grooves and bulges, which considerably enlarger its surface area. It is highly connected with other parts of brain.  Hemispheres are the two divisions of Cerebral cortex. Though the two hemispheres of the brain are similar in many ways, yet the two sides of the brain differ in their anatomical chemical and electrical properties.

Two sides of the brain have primary responsibility for different functions. The tendency for one cerebral hemisphere to play a more dominant role than the other in controlling particular functions is called cerebral dominance.

THE LEFT HEMISPHERE

The Left Hemisphere of the cerebral cortex in the larger of the two halves contains a higher proportion of grey matter and is thought to be the dominant hemisphere. Language Centre is housed in the left cerebral hemisphere but for all right handed people.

Corpus Collosum

The two hemisphere of the cerebral cortex are interconnected by a series of fibers called the corpus collosum. Through corpus collosum, one side of our cortex remains in complete contact with the other. Experiments confirm that speech production is a left hemisphere function in a greater majority of people. Left hemisphere can be given credit for most of our language skills and our reliance on language, which is very important matter; processing of certain verbal information is also involved in it.

THE RIGHT HEMISPHERE

Involves in the processing of visually presented information, skill in the visual arts; drawing and painting is associated with the right hemisphere more than left. The right hemisphere is also credited with being more involved in emotionality. A major task of right hemisphere is the appreciation. Patients with right hemisphere damaged are more likely to have perceptual and attentional problems, including serious difficulties in spatial orientation.

Lobes of the Brain

Each hemisphere has four major divisions called lobes.

FRONTAL LOBE

It is located at the front of the brain and covers the largest area. The portion of the cerebral cortex behind the forehead is involved in the Centre of voluntary muscles, intelligence and personality. The frontal lobe of humans is especially large when compared with those of other animals. Neuroscientists view that the frontal cortex is an important index of evolutionary advancement.

 Another important part of the frontal lobe in the pre-frontal cortex, which is the front of the motor cortex; it is involved in higher cognitive functions, such as planning and reasoning.

 TEMPORAL LOBE

Temporal lobe is located at the temples within each side of the brain. It is the portion of the cerebral cortex, just above the ears. It is involved in language processing, memory and  hearing,. The temporal lobe has a number of connections to the limbic system. Due to its damage, individual cannot file experience into long term memory.

PARIETAL LOBE

Parietal lobes are wedged in behind the frontal lobe and above the occipital and temporal lobes. It is involved in registering spatial location, attention and motor control.

At front of the parietal lobe, somato-sensory cortex process information about body sensation.

There is considerable integration and connection between any two or more lobes and between lobes and other parts of the brain.

OCCIPITAL LOBE

They are located at the very back of the brain.it responds to visual stimuli. Different areas of occipital are connected to process information about such aspects of visual stimuli as their color shape and motion. A stroke or wound in the occipital lobe can cause blindness or at a minimum, wipe out a portion of person’s visual filed.

AREAS OF CORTEX

There are three major areas of cortex; sensory areas, motor areas and associative areas.

SENSORY AREAS

It is the area where impulses from sense receptors are sent. It receives information from senses. The sense which is activated deals with its own sensory area, reflecting their relative importance to us. Large areas of the cerebral cortex are involved with vision and hearing. Entire occipital lobe processes visual information. Auditory impulse ends up in large centers in the temporal lobes.

Our body senses from different body parts; send impulses to a strip at the very front of the parietal lobe. Some parts of the body, even some very small ones, are processed in larger area of the cortex than the other parts of the body.

MOTOR AREAS

Some of our actions originate below the cerebral cortex. Although some lower brain centers may be involved. It is fair to say most voluntary activity originates in the motor areas of the cerebral cortex, in strips, at the very back of our frontal lobes.

ASSOIATIVE AREAS

Higher mental processes occur in associative areas. After sensory and motor areas, the remaining area is called associative area. Here sensory input is associated with motor responses. Cognitive functions such as problem solving, remembering and thinking occur here. There are three associative areas in each hemisphere; frontal, parietal and temporal. Pierre-Paul Broca (1824-1880) discovered that most language and speech behaviors are localized in the frontal associative area.

Damage to the very front of front of frontal lobes may interrupt and destroy the abilities to plan ahead, think quickly or think things through, there are no discontinuities in the brain, no independent channels traverse it, nor is its territory divisible into areas that house autonomous processors.

Scientists have found that the associative cortex is involved in linguistic and perceptual functioning. Associative areas process information about sensory input and motor output. The highest intellectual functions such as thinking and problem solving occur in the associative cortex.

Brain Thalamus Function

It is positioned right below the cerebral cortex and is ultimately involved with its functioning. Major role of thalamus is to process information from the senses. Many impulses from the cerebral cortex to lower brain structures, the spinal cord, and out to the peripheral nervous system also pass through the thalamus.

Thalamus collects and directs sensory messages to the appropriate areas of the cerebral cortex.  Messages from our lower body, our eyes, ears and other senses pass through the thalamus.it also has a role in a person’s normal pattern of wakefulness and sleep. That is why it is considered sensory relay station, as it sends impulses to the appropriate areas of the cerebral cortex.

BASAL GANGLIA

Above the Thalamus and under the cerebral cortex, lie larger clusters or ganglia, of neurons called basal ganglia.

The basal ganglia work with the cerebellum and the cortex to control and coordinate voluntary movements. Basal ganglia enable people to engage in habitual behaviors, such as riding a bicycle. Individual with its damage suffer from either unwanted movement, or too little movements.

Hypothalamus Function

• The hypothalamus is located near the limbic system. It is involved in our innovational and emotional reactions.
• Its major responsibility is to monitor critical internal bodily functions.                                     
• It controls eating behavior and is sensitive to the amount of fluid in our bodies i.e. indirectly gives rise to the feeling of being thirsty.
• The hypothalamus also acts as a thermostat, triggering several autonomic reactions i.e. should we become too warm or cold.
• Among other things, it also influences many functions of endocrine system.
• Furthermore, it is involved in aggressive and sexual behaviors and regulates many hormones.

LIMBIC SYSTEM

The limbic system is a collection of structure rather than a single unified one. It controls many complex behavior patterns that we usually think of as instinctive. Within the human brain, parts of the limbic system are involved in display of emotional reactions.

Its two principal structures are; AMYGDALA SEPTUM AND HIPPOCAMPUS.

The world AMYGDALA, taken from Latin, meaning “almond shape”, Amygdala is located with the base of temporal lobe. Amygdala is involved in the discrimination of objects that are necessary for the organism’s survival, such as approved food, mates and social rivals.

Neurons in Amygdala often fire selectively at the sight of such stimuli, its lesion can cause the animals to attempt to eat, fight or mate with inappropriate objects. It is also involved in emotional awareness and expressions through its many connections with higher and lower regions of the brain. Amygdala also produces reaction of rage and aggression with stimulated.

SEPTUM (another part of limbic system) has the opposite effect.  It reduces the intensity of emotional reactions when stimulated. The impact of amygdala and septum on emotional reaction is quite immediate and direct in non _humans.

HIPPOCAMPUS is also a part of limbic system. It is involved in formation of memories. People with damaged hippocampus are unable to remember events for short periods of time. It has special role in storage of memories. Brain is the most & important part of human body, Human Brain Anatomy.

MID BRAIN

It is between the fore brain and hind brain. Many nerve fibers systems ascend and descend to connect the higher and lower portions of brain. It works as relay information between the grain and the eyes and ears. The ability to attend to an object visually is linked to one bundle of neurons in the midbrain.

Hind Brain Function and Structure

It includes

1. Pons
2. Medulla Oblongata
3. Cerebellum
4. Reticular activating system
5. Brain Stem

Pons Brain Function

Just above the medulla is the pons, it serves as a bridge between brain and spinal cord. Centers in the pons are responsible for the rapid movement of our eyes, which occurs when we are asleep and dreaming. Other pons centers are involved in determining our cycle of being awake and being sleep.

MEDULLA OBLONGATA

The very lowest structure of the brain is the medulla oblongata whose motor functioning involves involuntary reflexes. There are many small structures within the medulla that control each function as reflexive eye and tongue movements.

Medulla contains the centers that control breathing and reflexes, monitor the muscles of the heart to keep it beating rhythmically.

At the medulla, nerve fibers to and from the brain, cross over from left to right and vice versa. By and large, the left side of brain receives impulses from, and sends impulses to; and receives messages from the right side of the brain. This process of crossing fibers from one side of the body to the opposite side of the brain is called cross-laterality and it takes place in the brain stem.

CEREBELLUM

It is a brain stem structure whose major function is to smooth and coordinate rapid movement because of the close relationship between body movement and vision many eye movement originated in the cerebellum, movement of tongue, lips and mouth are coordinated. A person with damaged cerebellum may appear to be quit drunk. It is also called the little brain because damage in cerebellum disturbs the motor activity.

RETICULAR ACTIVATING SYSTEM

It is complex network of nerve fibers that begins down in the brain stem and works its way up, through and around other structures, all the way to the top portion of the brain. Reticular activating (RAS) is involved in determining our level of activation or Arousal. It influences whether we are awake or attentive, sound sleep or at some level in between.   

BRAIN STEM

It includes much of the hind brain and mid brain and is so called because it looks like stem. It is the brain’s innermost region and oldest one. Therefore, it is called central core. The rain stem beings where the spinal cord enter the skull and swells slightly, forming the medulla. Clumps cells of the brain stem determine alertness and regulate basic survival function, such as breathing, heart beat and blood pressure.