Jennifer Ingrum 02/01/11
The Central Nervous System or (CNS) is located in the center portion of the body as its name implies. The (CNS) is made up of the brain and the spinal cord. Our brain is in control of many very important body functions and sensations like these for example: sleep, muscle movement, memory, sexual activity, emotions, hunger and thirst. Our spinal cord extends several types of nerve fibers from the brain acts like a switching and relay terminal for the peripheral nervous system as is stated in Mosby’s Dictionary. The 12 pairs of cranial nerves emerge directly from the brain Sensory nerves and motor nerves of the peripheral system leave the spinal cord separately between the vertebrae but unite to form 31 pairs of spinal nerves containing sensory fibers and motor fibers. More than 10 billion neurons constitute but one tenth of the brain cells; the other cells consist of neuroglia that support the neurons. The neurons and the neuroglia form the soft, jellylike substance of the brain, which is supported and protected by the skull. The brain and the spinal cord are composed of gray matter and white matter. The gray matter primarily contains cells and associated processes; the white matter consists predominantly of bundles of myelinated nerve fiber. The Peripheral nervous system or (PNS) extends from the (CNS) and includes the cranial and spinal nerves that connect the brain and spinal cord, respectively, to peripheral structure such a skin surface and the skeletal muscle. As recorded in our manual Structure Functions of the Body. There are additional structures Autonomic Nervous System or (ANS) that are considered a part of (PNS). They connect the brain and spinal cord to various glands in the body and to the cardiac and smooth muscle in the thorax and abdomen. Mosby’s Dictionary tells us; Sensory, or afferent, peripheral nerves transmitting information to the (CNS) and motor, or efferent, peripheral nerves carrying impulses from...
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