Maintenance of the Body
lines the internal surface of the ﬁbrous pericardium. At the su-
perior margin of the heart, the parietal layer attaches to the large
arteries exiting the heart, and then turns inferiorly and contin-
ues over the external heart surface as the
(“upon the heart”), which is an integral
part of the heart wall.
Between the parietal and visceral layers is the slitlike
, which contains a ﬁlm of serous ﬂuid. Te serous
membranes, lubricated by the ﬂuid, glide smoothly past one an-
other, allowing the mobile heart to work in a relatively friction-
Coverings of the Heart
Te heart is enclosed in a double-walled sac called the
. Te loosely ﬁtting superﬁcial part of this sac
. Tis tough, dense connective tis-
sue layer (1) protects the heart, (2) anchors it to surrounding
structures, and (3) prevents overﬁlling of the heart with blood.
Deep to the ﬁbrous pericardium is the
a thin, slippery, two-layer serous membrane that forms a closed
sac around the heart (see Figure 1.10, p. 19). Its
Body of T
Location of the heart in the mediastinum.
Relationship of the heart to the
sternum, ribs, and diaphragm in a person who is lying down (the heart is slightly inferior to this
position in a standing person).
Inferior view of a cross section showing the heart’s relative
position in the thorax.
Relationship of the heart and great vessels to the lungs.