. The eclectic guide to health; or, Physiology and hygiene ... by the closing of If the fingers are placed lightly on the pulse,at the wrist, the beating may be counted. Under ordinarycircumstances, the heart contracts about seventy-two timesper The time occupied in contraction is less thantwo thirds of the whole interval of one beat, so that themuscles of the heart rest more than one third the the seasons of rest thus gained are extremely short,they amount to more than eight hours daily. 75. The arteries are the tubes that conduct the bloodfrom the heart. Th
. The eclectic guide to health; or, Physiology and hygiene ... by the closing of If the fingers are placed lightly on the pulse,at the wrist, the beating may be counted. Under ordinarycircumstances, the heart contracts about seventy-two timesper The time occupied in contraction is less thantwo thirds of the whole interval of one beat, so that themuscles of the heart rest more than one third the the seasons of rest thus gained are extremely short,they amount to more than eight hours daily. 75. The arteries are the tubes that conduct the bloodfrom the heart. They subdivide into a vast number of smallbranches, so as to convey the blood to every part of thesystem. The pulmonary artery receives the blood from theright ventricle, and distributes it to the lungs to be aorta receives the blood from the left ventricle andsupplies it to the tissues of the body for their arteries are formed of very tough, elastic substance,and, when empty, resemble rubber tubes. The arteries have 8o a smooth lining, and are comparatively straight, so as notto lessen the force given to the blood by the heart. Theyare placed near the bones, and pass beneaththe great muscles, in order that they maybe shielded from danger. When they arecut or injured, there is -great danger ofbleeding to death. The blood in thearteries flows in jets, because of the beat-ing of the heart. In Fig. 35, we see aportion of a large artery. In the lowerpart of the figure, the artery is representedas cut open, to show the absence of Capillaries.—The minute, hair-liketubes, into which the arteries finally divide,are called capillaries. See Fig. 36. Theyare so extremely small that they are visibleonly by the aid of the microscope. Theyof an inch in diameter. The skin, except-ing the cuticle, is so full of these tiny vessels, that thepoint of a needle can not enter it without breaking someof them so that the blood flows out. The other m
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