Friday, December 10, 2010

Development of the human brain

By now, you should have an understanding of what the brain is from my previous post. I have been wondering what would make the human brain different from other species such as monkeys. When the human brain is beginning to develop, how does it develop and then how does it work. Also, are there any differences between the brains of males and females? If the answer is “yes”, then what are these differences?  I have learned the basic concept about the human brain from Human Anatomy class. However, the material that this class provided was not enough to answer my curious questions.  For this reason, I would like to research and discuss the above issues in depth.  
The human brain is a dynamic organ composed of trillions of neurons, or brain cells and it is the portion of the central nervous system that lies within the skill in vertebrates. Neurons communicate with one another through dendrites, which function as branches connecting one cell to another. The human brain is the most complex and important part of our body because it continues to develop after our birth.  85% of our brain's  development will happen after birth.  Therefore, the brain requires a series of developmental processes that occurs through the addition, change, and movement of cells. The brain begins to develop in the embryo after three weeks of pregnancy. First, the neural plate developes and then it rolles up to form the neural tube on day 22.  After four weeks, the brain stem, cerebellum (small brain),  nerve sheathes, the nervous system and other parts are formed. Nerve cells begin to develop during week four of the pregnancy and finish when the baby is born.  These nerve cells are like a mass of unconnected electrical wires and govern our lives every day. The following pictures should help you to understand how the human brain developes.





According to “Infant and Child Brain Growth and Development”, an article on the Parenting Tips and Guide Info website, “Infant and child brain growth and development are one of the critical period in development process. An infant or child's brain is an organ that is still growing and growing. An infant or child’s brain will grow big, bigger, and still be growing from the original immature brain into the mature brain. During the period of 2 weeks after conception (pre-embryos), egg cell division occurs. While at 2-8 weeks of gestation, it referred to as the embryo.”
At birth the brain consists of 10 billion neurons. Development is primarily to connecting a process of the wires. What makes the wires connect? Each time a child is held, read to, or plays with a toy, these nerves make a connection. During the early years of life, these wires confirm to connect through our learning of certain tasks and sensory experiences, such as feeling, touching, seeing, hearing, and tasting. These tasks actually teach brain cells their jobs. A lack of such sensory experiences results in brain cells failing to make connections and eventually dying off. The wiring for sight and intelligence are developed during the third and fourth month of life. If the visual system is not stimulated during this time, the ability to form the connections for sight is lost. If a minor eye condition goes undiagnosed, they can experience lifelong vision problems because their brain development during this critical period was incomplete.

After birth, only mature nerve cells function, but new nerves or myelin sheathes are still growing. The growth of nerves will increase the number of glia cells; therefore, the brain increases in volume and weight, and the baby looks more intelligent. The human brain weights about 3.5 pounds. The first three years of life are a critical phase in brain development, because the brain is growing and changing rapidly in response to the emotional and intellectual of stimuli experienced by the child.  The effects of this emotional and intellectual development will not be seen until a child reaches the third grade. During these early years, 75 percent of brain growth is completed. According to the “At what Age is the Development of the Human Brain complete?” article on the eHow.,“a child who is read to has a much better chance of becoming a reader, and a child whose curiosity is encouraged has a better chance to become a lifetime learner.” Therefore, it is important to establish the basic brain wiring during this very early age. According to the same article, “Children who have experienced gentle, loving care and the establishment of firm connections with other people from a very young age appear to experience more even and full brain development. Likewise, children who are exposed to rich and varied stimuli including music, art, speech, and so forth tend to have better brain development over time. Neglect, abuse, and lack of exposure to a variety of experiences can actually harm a developing brain.”

The brain is the control center for movement, sleep, hunger, thirst, and virtually every other vital activity necessary to survive. The brain consists of two hemispheres. The left hemisphere processes information sequentially and is described as analytical because it specializes in recognizing parts which make a whole. It is most efficient at processing verbal information, language should not be considered as being 'in' the left hemisphere. This hemisphere is able to recognize that one stimulus comes before another and verbal perception and generation depends on the awareness of the sequence in which sounds occur. The right hemisphere organizes simultaneously. It specializes in a method that perceives and constructs patterns. It is most efficient at visual and spatial processing and it is thought that nonverbal stimuli are processed primarily in the right hemisphere. The brain is especially primed to acquire new skills through age 12. Languages are best mastered by age 10.

Each area of the brain has an associated function. The cerebellum is the hind part of the brain. It is made up of gray unmyelinated cells on the exterior and white myelinated cells in the interior. The cerebellum coordinates muscular movements and, along with the midbrain, monitors posture. It controls movements of the human body in space. The brain stem, that incorporates the medulla and the pons, monitors involuntary activities such as breathing and vomiting. The thalamus, that forms the major part of the diencephalon receives incoming sensory impulses and routes them to the appropriate higher centers. It works in conjunction with the corpus callosum, a neuron rich membrane, to connect the two hemisphere of the cerebrum. The hypothalamus occupying the rest of the diencephalon regulates heartbeat, body temperature, and fluid balance. The cerebrum occupies the topmost portion of the skull and splits vertically into left and right hemispheres. It is the largest part of the brain and makes up 85% of the brain’s weight. The cerebral cortex contains most of the master control of the body. here the ultimate analysis of sensory data occurs, and motor impulses originate that initiate, and inhibit the entire spectrum of muscle and gland activity. The left half of the cerebrum controls the right side of the body, and the right half controls the left side. Therefore, if a stroke occurs in the left half of the brain, then the right side of the body is affected.
There are several diseases of the brain such as stroke, coma, multiple sclerosis, meningitis Parkinson’s disease, cerebral palsy, and migraine headache. Stroke is damage to the brain due either to blockage in blood flow or to loss of blood from blood vessels in the brain. According to “Brain,” an article, on mamahealth.com, “Coma is an extended period of unconsciousness from which a person cannot be aroused even with the most painful stimuli. Multiple sclerosis affects transmission of electrical signals to nerve cells. Meningitis is an inflammation of the meninges. Parkinson’s disease is a disorder of the brain characterized by shaking and difficulty with walking, movement and coordination. Cerebral palsy is a group of disorders which are caused by injuries to the brain that occur during fetal development or near the time of birth. A migraine headache is a recurrent, throbbing headache usually felt on one side of the head.”  

 Below is a picture of all the areas of the human brain to help you to understand it better.
           

Males and females differ not only in their physical aspects and reproductive function but also in many other characteristics. This includes the way they solve problems. We know that males are more aggressive than females. Young males engage in more rough-and-tumble play than fmales and females are more nurturing. We also know that in general, males are better at a variety of spatial or navigational tasks. What is the root cause of the difference between female behavior? According to  “Sex differences in the brain,” an article on changelingaspects.com, “Parts of the corpus callosum, a major neural system connecting the two hemispheres, as well as another connector, the anterior commissure, appear to be larger in women, which may permit better communication between hemispheres. Perceptual techniques that measure brain asymmetry in normal-functioning people sometimes show smaller asymmetries in women than in men, and damage to one brain hemisphere sometimes has less of an effect in women than the comparable injury in men does.” 




My first goal in this paper is to have you understand that experiences early in life have an impact on the developing brain. Therefore, if you want your next child to have a high quality brain, then you need to pay attention to the development of the brain, thi attention should begin before a pregnancy, during the pregnancy, and after birth until the development of the infant and child brain is complete.  The first four years of life are especillary important because that is when the brain is built.  Possible reason for brain damage are caused by birth trauma or a lack or lipids (fats) in the diet at key stages in the early weeks after birth.


Source/words cite
At What Age Is the Development of the Human Brain Complete? | eHow.comhttp://www.ehow.com/facts_5817063_age-development-human-brain-complete_.html#ixzz176hc02oR

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