. Kirkes' handbook of physiology . d in fourpulmonary veins which enter the left auricle. The total capacity of theveins diminishes as they approach the heart; but their capacity exceeds bytwo or three times that of their corresponding arteries. The pulmonaryveins, however, are an exception to this rule. The veins are found afterdeath more or less collapsed, and often contain blood. They are usuallydistributed in a superficial and a deep set which communicate frequentlyin their course. The coats of veins bear a general resemblance to those of arteries, figure150. Thus, they possess outer, midd
. Kirkes' handbook of physiology . d in fourpulmonary veins which enter the left auricle. The total capacity of theveins diminishes as they approach the heart; but their capacity exceeds bytwo or three times that of their corresponding arteries. The pulmonaryveins, however, are an exception to this rule. The veins are found afterdeath more or less collapsed, and often contain blood. They are usuallydistributed in a superficial and a deep set which communicate frequentlyin their course. The coats of veins bear a general resemblance to those of arteries, figure150. Thus, they possess outer, middle, and inner coats. The outer coat isconstructed of areolar tissue like that of the arteries, but is thicker. In someveins it contains muscular cells arranged longitudinally. The middle coat THE VEINS I, is considerably thinner than that of the arteries; it contains circular un-striped muscular fibers mingled with a large proportion of yellow elastic andwhite fibrous connective tissue. In the large veins near the heart the middle. Fig. 150.—Transverse Section through a Small Artery and Vein of the Mucous Membraneof a Childs Epiglottis; the artery is thick-walled and the vein thin-walled. .4, Artery; the letteris placed in the of the vessel, e. Endothelial cells with nuclei clearly visible; these cellsappe r very thick from the contracted state of the vessel. Outside it a double wavy line marksthe elastic tunica intima. m, Tunica media consisting of unstriped muscular fibers circularly ar-ranged; their nuclei are well seen, a, Part of the tunica adventitia, showing bundles of connective-tissue fiber in section, with the circular nuclei of the connective-tissue corpuscles. This coat grad-ually merges into the surrounding connective tissue. V, The lumen of the vein. The other lettersindicate the same as in the artery. The muscular coat of the vein, m, is seen to be much thinnerthan that of the artery. X 350. (Klein and Noble Smith.)
Size: 1238px × 2018px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectphysiology, bookyear1
