I have covered some of the brain’s functions in the past week or so in the series on Seasonal Affective Disorder. In 2017 apart from the weekly A-Z of common conditions, I will be repeating previous posts on the body.. However, in a slightly different order than before in a Top to Toe look at the major organs and their functions.
I appreciate and that many of you will have read these posts before but I hope that those of you new to the blog will find interesting.
For me, the brain has always been a fascinating part of the body as it is this organ rather than our hearts that makes us the person we are.
I remember the first heart transplant in 1967. The operation hit the headlines and because we had so recently left Cape Town I found it even more exciting. Dr. Christiaan Barnard pushed the boundaries of not just surgery but our understanding of the heart. Today the heart is just one organ that is transplanted and we also now have the ability to build artificial organs to either replace diseased parts of the body or temporarily keep us alive.
However, it is unlikely in my lifetime or for several generations to come that there will be a viable way to transplant or artificially replace our brains. There is a scientist preparing to do a full head transplant in Europe for a paraplegic young man who wants to take the huge risks involved to live a normal life.. I do feel for him and wish them well.
The brain is not just an organ that determines our who we are mentally but is also the control centre for the operations throughout our bodies. Without it we would not take that breath, swallow or digest our food efficiently. Despite its huge power and necessity we tend to take it for granted and rarely think of it in terms of nutrition or providing it with oxygen and hydration.. Of all our organs in the body, the brain is king and needs to be treated as such.
I fear losing my marbles, more than my general health. I have seen first-hand how dementia in the elderly turns a vibrant and capable person into a dependent and frightened individual. Some dementia is unavoidable but as you will see, most is definitely not a normal progression of old age.
I am going to do a very brief introduction to this amazing organ because I find that if you can understand the importance of the structure and workings of certain parts of your body you will treat it with respect.
The evolution of the brain.
It is the evolution of this organ which has distinguished us from all other living creatures. Apart from managing our life on an everyday basis, this organ is the only one we can share with others whilst alive. All the advances in science and medicine are made possible by the workings of this powerful organ and taking care of it should be our number one priority.
One of our challenges is to keep our bodies fit, healthy and functioning to a ripe old age. How wonderful to be able to look back at a lifetime of 90 or 100 years and remember every minute of it, every person we have ever met and every experience we have enjoyed. It is possible, but if the current trend of eating processed foods with poor nutritional value increases, we will begin to diminish our brain power and risk ending our lives not even remembering our own names.
Apart from direct trauma to the brain, resulting in long term damage, or genetic risk factors, it is more probable for brain cell death to be the result of nutritional deficiency or the effects of a stroke. Both of these conditions are directly affected by our lifestyle choices and diet.
Like all our other major organs, the brain requires a complex combination of oxygen and nutrients to sustain, nourish, repair and renew itself. It is not good enough to just eat a healthy diet. Nutrients need to get access to the brain and there are only a couple of options. The main arterial route into the brain, taking oxygen rich blood with the necessary nutrients is the Carotid Artery.
Like all arteries that supply blood to the various parts of the body such as the heart and brain, the carotid arteries can also develop a build-up of fat and cholesterol deposits, called plaque, on the inside. Over time this layer of plaque increases, hardening and blocking the arteries. This means that the oxygen and nutrients that your brain needs to function are very restricted. (see the blogs on cholesterol in the archive)
Unfortunately the knock-on effect of a narrowed artery is that plaque can break off and travel to the smaller arteries in the brain, blocking those pathways. Additionally, a blood clot can form and because the arteries have become so narrow it cannot pass and causes a blockage. This is what leads to a stroke.
The anatomy of the brain
Protected within the bony and tough skull, the brain is an organ of many parts. Each part works independently of the others but with a common purpose. There are excellent communication channels between each half of the brain and each functioning unit and this provides us with a seamless operation that enables us to see, breathe, think, smell, eat, process food, make love, talk and move amongst other things without really thinking about it.
The Brain Stem is the lower extension of the brain where it connects to the spinal cord. This is the survival centre of the brain and the Medulla Oblongata at the base of the brain-stem governs breathing, digestion, heart rate, blood pressure and our ability to be awake and alert. Most of the cranial nerves are from the brain-stem, which is the pathway for all the fibre tracts passing up and down from the peripheral nerves and spinal cord to the highest parts of the brain.
The Cerebral Cortex. The outermost layer of the cerebral hemisphere which is composed of grey matter. There are two hemispheres that are asymmetrical and both are able to analyse sensory data, perform memory functions, learn new information, form thoughts and make decisions. The two hemispheres however have different abilities. The left hemisphere is the serious side of our brain that can interpret information, do mathematics, learn language and reason. The right hemisphere is more the fun side of the brain able to process an amazing amount of sensory input in seconds to provide a complete picture of the immediate environment. This side also governs functions such as dancing or complicated movements and we also store our visual and auditory memories here.
The Corpus Callosum connects the two hemispheres to allow them to communicate with each other. This is essential if we for example want to combine the two individual abilities into one. Taking a complicated language such as music and playing it on an instrument for example would require co-ordination between the two sides of the brain.
The two hemispheres have different lobes and the Frontal lobes are for reasoning and memory. At the front of these lobes you will find the Prefrontal areas, which determine our ability to concentrate, reason and elaborate on information. They also are sometimes called the Gatekeeper of the brain as they govern our judgement and our inhibitions. Our personality and emotional traits are also sited here as well as our movement capabilities and language skills. Damage to the frontal lobes may result in loss of recent memory, confusion, inability to concentrate, difficulty in taking in new information and behavioural disorders.
The Parietal lobes are located behind the frontal lobes at the top of the brain and again have different duties within the scope of the brain. The right lobe enables us to find our way around spaces both those we are familiar with and new ones that we encounter. The left lobe enables our ability to understand spoken and written language.
The Parietal lobes also contain the primary sensory cortex, which controls sensation, or touch pressure and behind this cortex is an area which controls finer sensations such as texture, weight, size and shape. Damage to this part of the brain can leave a person unable to discriminate between the various sensory stimuli or to be able to locate and recognise parts of their own body. They may also lose the ability to translate the speech into the written word.
The Occipital Lobes are right at the back of the brain and they process visual information and not only are these lobes responsible for visual reception but they also contain association areas that help us recognise shapes and colours. Damage to this area will affect the sight.
The Temporal lobes are on each side of the brain about level with the ears. These lobes allow us to tell one smell from another and one sound from another. They also help in sorting new information and are believed to be responsible for short-term memory. Again the two separate lobes have different responsibilities. The right lobe is mainly involved in visual memory such as pictures or faces and the left lobe remembers words and names. Damage to this part of the brain may result in loss of hearing, panic and behavioural problems.
Within the brain is the Limbic system, which contains our smell pathways and also some very important glands that affect our sex drive, anger and fear mechanisms and our emotions. These pathways are of vital importance to the efficient running of our operational systems within the bodies and the health of these glands and pathways will have an impact on our general health and longevity. Damage to this part of the brain can result in a loss of the sense of smell, agitation, loss of control of emotions and loss of recent memory.
Next time – How the brain develops from conception to adulthood.
©sallygeorginacronin Just Food For Health 1999 – 2017