Anatomy is one of the oldest branches of medicine, with historical records dating back at least as far as the 3rd century bc; animal research dates back equally as far. Aristotle (384-322 bc) studied comparative animal anatomy and physiology, and Erasistratus of Ceos (304-258 bc) studied live animal anatomy and physiology (1). Galen of Pergamum (129-199 ad) is probably the most notable early anatomist who used animals in research to attempt to understand the normal structure and function of the body (2). He continuously stressed the cen-trality of anatomy and made an attempt to dissect every day because he felt it was critical to learning (3). His most notable work was De Anatomicis Administrationibus (On Anatomical Procedures), which when rediscovered in the 16th century, renewed interest in anatomy and scientific methods (2).
The Renaissance was a period of great scientific discovery and included advances in our understanding of human and animal anatomy. Andreas Vesalius (1514-1564 ad) was arguably the greatest anatomist of the era (4). He performed public nonhuman dissections at the University of Padua in Italy to teach anatomy and is credited with creating the field of modern anatomy (2). His immediate successors at Padua were Matteo Realdo Colombo (1510-1559 ad), who described pulmonary circulation and the atrial and ventricular cavities, and Gabriele Falloppio (1523-1562 ad), who is credited with the discovery of the Fallopian tubes among other things (4). Animal research flourished during this period because of a number of popular ideas launched by the christian church and Rene Descartes. The church asserted that animals were under
From: Handbook of Cardiac Anatomy, Physiology, and Devices Edited by: P. A. Iaizzo © Humana Press Inc., Totowa, NJ
the dominion of man and, although worthy of respect, could be used to obtain information if it was for a "higher" purpose (2). Descartes described humans and other animals as complex machines, with the human soul distinguishing humans from all other animals. This beast-machine concept was important for early animal researchers because, if animals had no souls, it was thought that they could not suffer pain. Furthermore, the reactions of animals were thought to be the response of automata and not reactions of pain (2).
The concept of functional biomedical studies can probably be attributed to another great scientist and anatomist, William Harvey (1578-1657 ad). He is credited with one of the most outstanding achievements in science and medicine: a demonstration of the circulation of blood, which was documented in his publication Exercitatio Anatomica De Motu Cordis et San-guinis in Animalibus (De Motu Cordis) in 1628. His work ushered in a new era in science, in which a hypothesis was formulated and then tested through experimentation (4). Many great anatomists emerged during this period and made innumerable discoveries; many of these discoveries were named after the individuals who described them, including several researchers who studied cardiac anatomy such as the eustachian valve (Bartolomeo Eustachio), the Thebesian valve and Thebesian veins (Thebesius), and the sinus of Valsalva (Antonio Maria Valsalva).
It should be noted that, during this time period, in addition to animal dissection, dissections on deceased human bodies were performed, but not to the degree that they are today. In fact, it is written that, in general, during the post-Renaissance era there was a serious lack of human bodies available for approved dissection. Often, bodies were obtained in a clandestine manner, such as grave robbing, or the bodies of executed criminals were provided for dissection. In spite of the lack of bodies for study, most structures in the human body, including microscopic ones, were described by various anatomists and surgeons between the 15th and early 19th centuries.
Early in the 19th century, the first organized opposition to animal research occurred. In 1876, the Cruelty to Animals Act was passed in Britain. It was followed in the United States by the Laboratory Animal Welfare Act of 1966, which was amended in 1970, 1976, and 1985. These two acts began a new era in how laboratory animals were treated and utilized in experimental medicine. Nevertheless, the necessity of animal research is still great; therefore, animals continue to be used for a variety of scientific purposes, including cardiovascular device research.
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