Lauren J. Sweeney

Lecturer in Biology


Ph.D. in Anatomy and Cell Biology, University of Nebraska Medical School, 1981; M.S., 1978
B.A. in Biology, University of Pennsylvania, Philadelphia, PA

Research Background and Current Interests

From my initial introduction to embryonic development in college courses, I have been intrigued by how a single cell could develop into a complex organism. I continue to be amazed at the unfolding story of complex gene programs that must be turned on to take that single cell through its many intermediate steps, as well as the many steps that rely on embryonic cells being in the right place at the right time to receive signals from each other in order to follow their appropriate path. I became particularly interested in the development of the cardiovascular system during my graduate research. The cardiovascular system is unique among organ systems in that it must function from the early stages of its own development, or the rest of the embryo will fail to develop normally, since most complex organisms outstrip their capacity to receive nutrients and oxygen by diffusion just as the development of their organ systems is beginning to take off. Interestingly, a number of defects in the development of this system are of little or no consequence to the development of the embryo itself, which can often be completely normal in all other respects. But with birth comes the need to properly route oxygenated and deoxygenated blood to separate paths, and any abnormally routed vessels or underdeveloped heart chambers quickly become a life threatening problem. My initial research was focused on analyzing the specific structure of congenital defects in human hearts, with an eye to using those details to suggest possible mechanisms underlying altered development. With this background, I tested the role of altered blood flow patterns by creating an experimental model of hypoplastic left heart syndrome in the chick embryo. My post-doctoral research focus then turned to one of the key features underlying all cardiac functioning, the role of changes in patterns of gene expression of the contractile proteins responsible for the particular characteristics of cardiac contraction. Different forms of the contractile protein filament myosin are expressed at different stages of heart development and maturity, and in different part of the heart at each of these stages. These different isoforms are capable of catalyzing different rates of contraction, since each form of myosin contains different ATPase activity levels. I documented transitions in the expression of this protein in both the chick and rat animal models, transitions that correlated in time and localization with several key functional developments.

My focus and interests in more recent years have transitioned from active research to using my training and experience as both a scientific illustrator and research scientist to create coordinated text and illustrations for subjects that I have spent years teaching, first on the medical school level and now on the undergraduate level. The first of these projects resulted in the publication of the medical embryology textbook, Basic Concepts in Embryology, in 1998.

Education publications:
Sweeney LJ, Brodfuehrer PD, and Raughley, BL (2004) An introductory biology lab that uses enzyme histo-chemistry to teach students about skeletal muscle fiber types. Adv Physiol Educ 28: 23-28.
Textbook: Sweeney LJ (1998) author and illustrator, Basic Concepts in Embryology: A Student's Survival Guide, McGraw-Hill Publishers, NY.
Selected research publications
Sweeney LJ and Kelley SW (1990) Histochemical and biochemical analysis of myosin expression during cardiogenesis in the rat. J Mol Cell Cardiol, 22: 361-370.
Kennedy JM, Sweeney LJ, and Gao L (1989) Ventricular myosin expression in developing and regenerating muscle, cultured myotybes, and nascent myofibers of overloaded muscle in the chicken. Med and Science in Sports and Exercise, 21: S187-197.
Sweeney LJ, Kennedy JM, Zak R, Kokjohn K, and Kelley SW (1989) Evidence for expression of a common myosin heavy chain phenotype in future fast and slow skeletal muscle during initial stages of avian embryogenesis. Develop Biol 133: 361-374.
Sweeney LJ (1988) A molecular view of cardiogenesis, Experientia 44: 930-936.
Kennedy JM, Eisenberg B, Reid SK, Sweeney LJ, and Zak R (1988) Nascent muscle fiber appearance in overloaded chicken slow-tonic muscle. Am J Anat 181: 203-215.
Sweeney LJ, Zak R, and Manasek FJ (1987) Transitions in cardiac isomyosin expression during differentiation of the embryonic chick heart. Circ Res 61: 287-295.
Manasek FJ, Icardo J, Nakamura A, and Sweeney LJ (1986) Cardiogenesis: developmental mechanisms and embryology. In, "Heart and Cardiovascular System" (HA Fozzard, RB Jennings, E Haber, AM Katz, and HE Morgan, eds), Raven Press, New York pp 965-986.
Sweeney LJ, Nag AC, Eisenberg B, Manasek FJ, and Zak R (1985) Developmental aspects of cardiac contractile proteins. Basic Res. Cardiol 80, Suppl 2: 123-127.
Sweeney LJ (1985) Contractile protein expression in embryonic heart development. In, "Cardiac Morphogenesis" (Proceedings, NIH Workshop, VM Ferrans, GC Rosenquist, and C Weinstein, eds), Elsevier Science Pub Co, NY, pp 78-84.
Sweeney LJ, Clark WA, Umeda PK, Zak R, and Manasek FJ (1984): Immunofluorescence analysis of the primordial myosin detectable in embryonic striated muscle.Proc Natl Acad Sci (USA)81:797-800.


Bryn Mawr College

Introductory Biology (Biology 102, Spring semester: "Organisms to Populations")
Histology (Biology 204): lecture and lab course
Developmental Biology (Biology 271): lecture and lab course
Biology Department Senior Seminars:

Topics in Cellular and Organismal Physiology (Biology 380)
Senior Seminar and Research Tutorial in Developmental Neurobiology (Biology 394)
Senior Seminar in Physiology (Biology 392)

Medical School
Loyola University Stritch School of Medicine (1986-1996):
Medical Histology
Medical Embryology
Graduate Developmental Biology
Graduate Cell Biology
Graduate Cell and Molecular Biology

University of Illinois at Chicago Medical School (1993-1996): Medical Embryology  

University of Nebraska Medical School:Gross Anatomy (1980-81)

Contact Dr. Sweeney at: lsweeney at brynmawr-dot-edu ("phonetic" spelling designed to thwart spam!)