Nerve Mechanics Essay

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.

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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 the brain usually travel together but separate at the cord level into the posterior sensory root and an anterior motor root.Fibers innervating the body wall are designated somatic. Those supplying internal organs are termed visceral. The autonomic system includes the peripheral nerve involved in regulating cardiovascular respiratory, endocrine, and other automatic body functions. Nerves in the sympathetic or thoracolumbar division of the autonomic system secrete norepinephrine and cause peripheral vasoconstriction, cardiac acceleration, coronary artery dilation, bronchodilation, and inhibition of peristalsis.

Parasympathetic nerves which constitute the craniosacral division of the autonomic system secrete acetylcholine; cause peripheral vasodilation, cardiac inhibition, and bronchoconstriction; and stimulate peristalsis. Injury to a peripheral nerve results in loss of movement and sensation in the area innervated distal to the lesion. The Autonomic Nervous System (ANS) is certain motor neurons that conduct impulses form the spinal cord or brainstem these types of tissue glandular epithelial tissue, smooth muscle tissue, cardiac muscle tissue. ANS) regulates involuntary function like the heartbeat, contractions of stomach and intestines.

Looking at the motor nerves that control the voluntary actions of skeletal muscles are sometimes called the somatic nervous system. There are two divisions of (ANS) called the sympathetic nervous system and the parasympathetic nerve system.ReferencesMosby’s Dictionary of Medicine, Nursing & Health Professions 8th edition Issued by: Kaplan University retrieved, February 1st 2011

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