The APA style allows for in-text citations, direct quotations, and endnotes and footnotes. It is also enables the author to use the past tense of verbs in the reportage. Standards of the APA style include: 1  Bibliographic list of references. 2  Alphabetical order by author in the bibliographic list, then chronological by work.
Function [edit]. The pericardial fluid reduces friction within the pericardium by lubricating the epicardial surface allowing the membranes to glide over each other with each heart beat.
1. 3 Layers in arterial walls (are also known as tunics): a. Tunica interna-innermost layer. Also known as the tunica intima. 1) Surrounds a central blood-containing space known as the lumen. 2) Lined with endothelium (simple squamous epithelium). This tissue. reduces friction as blood moves through the lumen. b. Tunica media-composed primarily of smooth muscle tissue and elastic tissue. 1) This smooth muscle is regulated by the autonomic nervous system. and various chemicals. 2) Vasoconstriction (reduction in lumen diameter due to smooth muscle. contraction) and Vasodilation (widening of the lumen due to smooth. muscle relaxation) both occur in the tunica media.