Lesson 9: The Nervous System (page 1 of 19)


Overview of Lesson 9
The Nervous System


Brown Rice vs White Rice

When brown rice is produced only the outermost layer, or the husk, is removed from the grains of rice. To produce white rice, the next layers underneath the husk (the bran layer and the germ) are also removed, leaving mostly the starchy endosperm. The problem, of course, is that the bran and germ layers are where most of the vitamins, minerals and oils are contained. When the bran layer is removed to make white rice, the oil in the bran is also removed. Rice bran oil helps lower your bad cholesterol. Other nutrients that are lost in white rice are fatty acids and fiber. So in addition to having greater nutritional value, brown rice is also more beneficial than white rice when it comes to constipation.

Because white rice is so nutritionally deficient, in the US, the Food and Drug Administration (FDA) requires that food suppliers “enrich” their white rice with some of the missing nutrients, such as vitamin B1, B3 and iron. But there are many important nutrients that are not put back into white rice, including magnesium. Brown rice consequently has over four times the magnesium content as white rice. Magnesium is a very important mineral, essential for healthy nerve function and for heart health. A recent study estimated that as many as 80% of Americans are magnesium deficient, attributed mostly to the high consumption of refined foods such as white rice. Is there any wonder why heart-related diseases, such as heart attack and stroke, are the number one killers of Americans?


GABA (gamma-Aminobutyric acid) is a helpful amino acid found naturally in brown rice. When consumed over time it can help to calm the nerves while improving mental clarity, lower blood pressure, improve kidney function, and reduce sleeplessness. GABA is the brain’s natural calming agent. The GABA content of brown rice can be greatly increased if the rice is slightly sprouted before it is cooked. The rice doesn’t have to actually sprout, but the tip of the grain will swell slightly. To make GABA rice, soak brown rice in warm water for 20 hours before cooking. Change water every 4 to 6 hours if it becomes slightly smelly. Rinse before cooking. Since the rice has already absorbed some water, it will require slightly less water (and time) to cook.

The nervous system consists of the brain, the spinal cord, and the network of nerves throughout the rest of the body. It is sometimes called the master system, since it regulates and coordinates every other body system. The nervous system provides a rapid means for the various parts of the body to communicate with each other. It allows us to adjust to the world around us and cope with the challenges of life. It influences how we act or react to stress. The fight or flight response is a good example. This is a hormonally stimulated state to prepare the body for an upcoming threat or challenge.The nervous system is composed of two major parts; the central nervous system (CNS) and the peripheral nervous system (PNS). The central system is the brain and spinal cord, and is where most information is processed. The peripheral system is the network of nerves throughout the rest of the body. The peripheral nervous system allows signals to travel between the central nervous system and the body’s sensory receptors and motor effectors, such as the muscles.

The Brain
The Central Nervous System (CNS) consists of the brain and spinal cord.

The CNS and PNS are anatomical divisions of the nervous system. The nervous system is also divided into two physiological (or functional) divisions — a voluntary system, which as the name implies is concerned with voluntary actions such as muscle movement; and an involuntary or automatic system referred to as the autonomic nervous system.


The Autonomic Nervous System

An automatic, or autonomic, nervous system controls basic functions of the body that we do not normally have conscious control over, such as the heart rate, digestion, breathing and blood flow. These involuntary actions are controlled by the opposite and antagonistic actions of the two divisions of the autonomic nervous system – the sympathetic and the parasympathetic divisions. Most organs receive impulses from both divisions and under normal circumstances they work together for proper organ function and adaptation to the demands of life.

The sympathetic system tends to stimulate a particular function while the parasympathetic tends to calm. Normally the two nerve supplies create a balance. However, if the body is stressed, such as in the fight or flight response, the sympathetic nervous system dominates causing an increase in heart rate, breathing, blood pressure and blood sugar levels. This prepares the body for quick and strenuous action. When the emergency situation has passed the parasympathetic system takes over and decreases the heart and breathing rates and diverts blood supply back to activities such as digestion and food absorption.

Problems may occur when the autonomic nervous system is out of balance. For example, over-stimulation of the sympathetic nervous system can lead to such problems as anxiety, hypertension, and digestive disturbances. Over-stimulation of the parasympathetic nervous system can result in low blood pressure and fatigue. Both imbalances lead to poor adaptation to stress.

Which division of the autonomic nervous system is called upon to stimulate and prepare the body for emergency action, such as in the “fight or flight” response?


(Select the best answer and click on the “Continue” button.)