nervous system responsible for coordinating the many activities performed inside and outside the...
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Nervous System
Responsible for coordinating the many activities performed inside
and outside the bodyEvery square inch of the human body is supplied with fine fibers known as nerves; there are over 100 billion nerve cells, known as
neurons, in the body
Neurology
The study of the nervous system and its disordersThe nervous system is one of the most important systems of the body; controls and coordinates the function of all other systems, making them work harmoniously and efficiently
Cerebrospinal System Also known as the central nervous systemConsists of the brain, spinal cord, spinal nerves & cranial nervesIt controls consciousness and all mental activities, voluntary functions of the five senses
Seeing, hearing, feeling, smelling & tasting
Controls voluntary muscle actions, including all body movements and facial expressions
Peripheral Nervous System
Made up of sensory and motor nerve fibers that connect the peripheral (outer) parts of the body to the central nervous systemIt has both sensory and motor nerves and carries messages to and from central nervous system
Autonomic Nervous System
Controls the involuntary musclesRegulates the action of the smooth muscles, glands, blood vessels and heart
Brain Spinal Cord
Brain is largest mass of tissue in the bodyAverage weight is 44-48 ouncesCentral power station of the body
Brain Spinal CordContains 12 pairs of cranial nerves
All of which originate in the brain & reach various parts of the head, face & neck
Spinal cord originates in the brainEnclosed & protected by spinal column
31 pairs of spinal nervesExtend from spinal cord to muscles & skin of trunk & limbs
Nerve Cell Structure & Function
Neuron or nerve cellPrimary structural unit of nervous system; composed of cell body & nucleus
DendritesTree-like branching of nerve fibers extending from the nerve ell that receive impulses from other neurons
Nerve Cell Structure & Function
Axon & Axon terminalSend impulses to other neurons, glands & muscles
NervesLong, whitish cords made up of bundles of fibers held together by connective tissue, through which impulses are transmitted
Types of NervesSensory nerves (afferent)
Carry impulses or messages from sense organs to the brain, where sensations of touch, cold, heat, sight, hearing, taste, smell, pain & pressure are experienced
Motor (efferent) nervesCarry impulses from brain to muscles; the transmitted impulses produce movement
Types of NervesMixed nerves
Contain both sensory and motor fibers and have the ability to both send and receive messages
ReflexAutomatic response to a stimulus that involves movement of an impulse from a sensory receptor along an afferent nerve to the spinal cord, and a responsive impulse along an efferent neuron to a muscle causing a reaction
Example: the quick removal of a hand from a hot object
Reflexes do not have to be learned