Are you aware that you actually possess six senses ? The sixth is a muscular sense responsible for directing your muscles intelligently to the exact extent necessary for each action you perform . For example , when you reach for an object , the sensory nerves linking the muscles to the brain stop your hand at the correct spot , This automatic perception of the position of your muscles in relation to the object is your muscular sense in action .

Muscles are bundles of fibers varying from one five-thousandth of an inch to about three inches . They have three unique characteristics , they can become shorter and thicker ; they can stretch ; and they can retract to their original positions . Under a high-powered microscope , muscle tissue is seen as long , slender cells with a grainy texture like wood .

More than half of a person's body is composed of muscle fibers , most of which are involuntary-in other words , work without conscious direction . The voluntary muscles , those that we move consciously to perform particular actions , number more than five hundred . Women have only 60 to 70 percent as much muscle as men for their body mass . That is why an average woman can ' t lift as much , throw as far , or hit as hard as an average man .

According to the selection , the muscular sense is used for________.

 Intelligent use of the muscles means that ________.

 Muscles are unique fibers because , they can________.

 Under a microscope , muscle cells appear to be________.

According to the selection more than half of a person body is composed of________.