. A healthy body. A textbook on anatomy, physiology, hygiene, alcohol, and narcotics. For use in intermediate grades in public and private schools . Fig. 40. (1) valves of a vein closed; (2) valvesof a vein opened. CIRCULATION. 121 Valves in the Veins. We found that tlicre were valvesin the heart to keep the blood from flowing in the wrongdirection ; and we find that there are many valves inthe veins for the same purpose. Fig. 40 shows thearrangement of these valves. In the vein marked 2the valves are open, and the blood is flowing in thedirection of the arrows without anything to prevent
. A healthy body. A textbook on anatomy, physiology, hygiene, alcohol, and narcotics. For use in intermediate grades in public and private schools . Fig. 40. (1) valves of a vein closed; (2) valvesof a vein opened. CIRCULATION. 121 Valves in the Veins. We found that tlicre were valvesin the heart to keep the blood from flowing in the wrongdirection ; and we find that there are many valves inthe veins for the same purpose. Fig. 40 shows thearrangement of these valves. In the vein marked 2the valves are open, and the blood is flowing in thedirection of the arrows without anything to prevent if the blood should attempt to flow in the oppositedirection, as shown in the vein marked 1, then the valveswould close and completely shut off the passage. How rapid is the Circulation? The heart contracts withsuch force that the flow of blood in the large vesselsnear it is very rapid, but when the blood passes throughthe minute capillaries, the rapidity of its current isgreatly diminished. The current in the veins is not sorapid as in the arteries, and is the slowest in the capil-laries. The heart contracts with such force and fre-quency
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Keywords: ., bookcentury1800, bookdecade1880, bookidhealthybodyt, bookyear1889
