Anatomy, physiology and hygiene for high schools (1900) (14594755210)

Identifier: anatomyphysiolo00hewe (find matches)
Title: Anatomy, physiology and hygiene for high schools
Year: 1900 (1900s)
Authors: Hewes, Henry Fox, 1867-
Subjects: Physiology Health education (Secondary) Human anatomy
Publisher: New York : American Book Company
Contributing Library: The Library of Congress
Digitizing Sponsor: The Library of Congress



Text Appearing Before Image:
its upper wall is the open-ing from the left auricle. Thisopening is covered by a valvemade up of two flaps, the bicus-pid or mifraJ (Greek niifra, head-•Iress ) valve. The bases of thesevalve flaps are fixed about theauric ulo-ventricular opening.Their edges are held by connec-tive tissue cords connecting withthe ventricular walls, the cJwrdcetendinece (Greek chorda, ^cord,and teuein, to stretch)- Thesecords keep the valve from pressing back into the auricleunder the pressure of the blood in the ventricle. The valveallows the free flow of the blood from auricle to ventricle,but stops any back flow from the ventricle when the ven-tricle contracts. In the front part of the ventricle, in frontof the auricular opening, is the opening to the aorta. Thisopening is covered by a valve consisting of three flaps, eachshaped like a half moon, the semilunar (Latin semi, half,and hiua, moon ) valve. This valve aHows the blood to flowfrom the ventricle to the aorta, but not back from the aorta.
Text Appearing After Image:
Heart, with aorta. CIRCULATION AND THE CIRCULATORY SYSTEM 157 At the base of the heart, to the right, separated from theleft auricle b) a partition or septum, is the right auricle.In the right wall of this auricle is the opening of the twolarge veins which col-lect the blood return-ing from the tissuesto the heart, the stqje-rior and inferior venacava (hollow). In the lower anteri-or part of the auricleis the opening of theright ventricle. Thisis covered by a three-flap valve, the tricus-pid (Latin tri^ three,and cuspis, spearpoint) valve. It pre-vents regurgitation(Latin re, * again,and gurgitare, to en-gulf) of the bloodfrom ventricle toauricle. The right ventriclelies in the lower partof the heart, to the right. It is separated from the left ventricle by a septum.The walls of this ventricle are thicker and firmer than thoseof the auricle, but less thick than those of the left ven-tricle. At the top of the ventricle, toward the front, is theopening to the pulmonary artery. This open