Anatomy & Physiology

Themes in Anatomy  Ambivalence  Art in medicine  Social responses

Galen & Anatomy  Dissection as public spectacle  Animals only

 Resulting errors –rete mirable –five lobed liver –uterine cotyledons –location of right kidney –veins originating in liver –arteries originating in heart

 The legacy: –For 1000 years after Galen’s death, his anatomical findings were accepted as true, even in the face of evidence to the contrary

Renaissance of Anatomy  Began to re-appear in medical schools in 14 th century  Purpose was to explain Galen, not to correct him

 Mondino de’ Luzzi (c )  Revived ancient anatomical knowledge  Anatomia  Reproduced most of the features of ancient anatomy

 Did not dissect  Used barber surgeon to do this  Dissected from the inside out, which damaged fragile structures & tissues  Did not challenge Galenic anatomy

Two Developments that Changed the Nature of Anatomy  Changes in technology of producing books  Rise of realism in art

Changes in Technology of Producing Books  Illustrations in books expensive and labour intensive  Early anatomy books contained few illustrations  Depended on presence of gifted artists

 Anatomical representations were not exact  Realism not as important as symbolism  Introduction of wood cuts made it easier to standardize illustrations

Realism  Michelangelo ( )  Da Vinci ( )  Both emphasized anatomical accuracy  Da Vince actually worked with cadavers

Da Vinci’s Anatomical Drawings o.html o.html

Rise in the Science of Anatomy  Berengario da Carpi (c ) –Denied existence of rete mirabile  Niccolo Massa (c ) –Anatomy of heart –Drew attention to fact that it was not perforated

 Why didn’t these findings challenge Galenic orthodoxy?  An alternative theory didn’t exist  Theory necessary to maintain presence in university

 Persistence of humoural theory  Dissection of healthy criminals did not often reveal solid pathology (pathology in tissues)

Vesalius  Born in Belgium in 1514  Died 1564  Educated at University of Paris  Appointed professor of anatomy at Padua

 Published Fabrica or On the Fabric of the Human Body in 1543 when he was 29  Contained over 200 anatomical drawings

 Did his own dissections  Dissected from the outside in  Many of his findings challenged Galenic anatomy

 The illustrations in the book are stunning, both artistically and in terms of anatomical accuracy  Likely done by a student of Titian’s

 Realdus Columbus ( ) –Described pulmonary transit of the blood  Still did not replace Galenic physiology

 Not until 1628 and William Harvey’s description of the circulation of the blood did Galen’s hold over anatomy end

Anatomy in the 19 th Century  Duffin provides good discussion of: –Why anatomy was detached from mainstream medicine until 19 th century –Why anatomy became important to medical schools  Another important story also exists

 Richardson: Death, Dissection and the Destitute  1832 Anatomy Act –Intended to de-commodify the human body –Had other consequences

 State turned bodies of paupers over to medical schools  Made dissection a hated punishment for poverty  Created significant cultural practices amongst the working class

Themes in Physiology 1. Vitalism vs. mechanism  Vitalism –theological ideas about soul & spirit –origin & phenomenon of life dependent on a force distinct from chemical or physical forces

 Mechanism –Related to chemical or physical forces

2. Methods of inquiry: teleology vs. empiricism  Teleology –belief in the possibility of uncovering the ultimate reason for a specific function –Rooted in theology

–Doctrine of 1 st causes: the “why question” –Belief in uncovering reasons why those things observed are as they are –Belief in vitalism –Associated with Galenism

 Empiricism – confined to observations & their immediate observable causes –Arose in 17 th century with the Scientific Revolution –Increasingly replaced teleology

–Concerned only with what can be observed & the immediate consequences –Focus on mechanics (physics) or chemistry –The “how” question

3.Speculation vs. Experimentation  Must not assume that experimentation had no place Galenism  Also must not assume that speculation does not occur within empiricism

 Emphasis shifted to experimentation rather than received knowledge (texts) & books with the Scientific Revolution

4.Rise of physiology as a distinct discipline or profession –Occurred in 19 th century

Galen & Physiology  Movement of the blood  Two types of blood –Venous –Arterial  Two vascular systems –Venous –Arterial

 Blood did not circulate; it was used up  Active component of heart was diastole (when it expands)  Arteries actively contracted and expended

Galen’s Medical Practice  Assessment of the pulse –21 normal pulses –27 abnormal pulses  Blood letting

Ibn al-Nafis (d C.E.)  Earliest recorded description of pulmonary circulation or the pulmonary transit of blood  Claimed septum between two ventricles of heart was impermeable (correctly)  Ignored, likely because of Galen’s greater fame

William Harvey ( )  Illustrates 2 important themes in history of medicine 1. advent of physiology 2. tension between teleology & empiricism

 Born in Folkestone, England  Studied medicine at Cambridge  Continued studies & graduated from University of Padua  Set up a successful medical practice in England  Member of Royal College of Physicians

 Physician to James I and Charles I  Lecture notes of 1616 indicate he still accepted Galen’s description of blood movement  Aware of transit of lungs  Believed heart pumped rather than sucked

 By 1628, concluded that blood moved in a circuit around the body  Published Anatomical Exercises on the Motion of the Heart and Blood in Animals, commonly known as De Motu Cordis

Galenic Anatomy

Harvey’s Anatomy

Supported this argument through a series of arguments 1. Quantification -calculated amount of blood that would have to be produced by liver if it was used up -demonstrated that this would require 540 lb. of blood/hr.

2. Experiments on a living human -ligatures to demonstrate movement of blood in the arm 3. Vivisection of animals 4. Understanding of how valves in veins worked

 De Motu Cordis reads like an empirical argument –evidence from several sources –careful refutation of previous teachings contrary to his findings  However, Harvey was a vitalist  Drew heavily on Aristotle’s writings to demonstrate ancient precedents for his findings

 Believed the heart was responsible for observed changes in colour of blood during the pulmonary transit  Powerful indicator of how theory shapes subsequent observations and interpretations

“So the heart is the beginning of life; the Sun of the Microcosm, as proportionably the Sun deserves to be called the heart of the world, by whose virtue and pulsation the blood is mov’d perfect, made vegetable, and is defended from corruption, and mattering, and this familiar household-god doth his duty to the whole body, by nourishing, cherishing, and vegetating, being the foundation of life, and the author of all”

The Response to Harvey  Heavy criticism from adherents of Galenic-Aristotlian theory  Harvey could not demonstrate capillary link between arteries & veins  His findings threatened other aspects of Galen

 Jean Riolan the Younger  Ultraconservative Galenist at University of Paris  Attempted to shore up Galen’s theory  Proposed that blood flowed (sluggishly) in aorta & vena cava, but not elsewhere

 Harvey’s findings embraced by those who opposed teachings of Galen & Aristotle  Rene Descartes ( )  Leading figure in Scientific Revolution  Mechanist/empiricist  Separation of mind and body

 Body a machine  Could be fixed  Unable to specify mind-body link –Neither can we

 Giovanni Alfonso Borelli ( ) –Iatromechanist –Conceived of body as a series of levers –Able to demonstrate mechanical forces on leg & foot muscles created by weight on the back

 John Mayow –Iatrochemist –Humans as units of combustion –Mouse & candle in the jar experiment –Demonstrated that candles & mice required the same kind of air to survive

 Embryology another example of the “make-over” of ancient learning during this era  Aristotle & epigenesis –Life begins as undifferentated material –Specific structures emerge from this material –Driven by an internal force

 Mechanical theory opposed this view  Descartes –Male & female seed contained particles from all parts of the individual –At conception, like parts attracted, and then grew larger

 Even other mechanists thought this was a lame theory  Replaced by Preformationism  Animals fully formed in their seeds  Simply grew larger

 Jan Swammerdam ( ) supported this view with experiments on tadpoles  Nicholas Malebranche (1672) proposed that all humans were present at creation as seeds & developed in successive generations

 Called en emboitement  Solved 2 problems –Explained existence of original sin –Explained where embryos came from

 Harvey opposed this view  Published On Generation in 1651  Based on observations & experiments on animals  Endorsed Aristotle’s view

 Development of microscope  van Leeuwenhoek ( )  Robert Hooke  Published Micrographia in 17 th century

 Early microscopic findings suggested that seeds of future generation might reside in females  Nicolas Steno –1667 –Discovered ovaries of dog-fish filled with eggs –Perhaps all future generations contained in females

 Regneir de Graff ( ) –Discovered Graffian follicles in humans –Mistook them for ova –Further support for female primacy over generation –Called ovist preformationism

 Fortunately for men, these findings were refuted by van Leeuwenhoek in 1677 –Described spermatozoa –Male once more assumed supremacy in generation

 Variations of Preformationism held sway until about 1740  Example of how intellectual fashions can influence science