Corneille Heymans Belgian physiologist, winner of the Nobel Prize in Physiology or Medicine in 1938 Date of Birth: 28.03.1892 Country: Belgium

1. Biography of Corneille Heymans
2. Early Life and Education
3. Research and Discoveries
4. Nobel Prize and Later Years

Biography of Corneille Heymans

Corneille Jean François Heymans was a Belgian physiologist and pharmacologist who was awarded the Nobel Prize in Physiology or Medicine in 1938. He was born in Ghent, Belgium to Jean and Marie Henriette (Hennin) Heymans. His father was a professor of pharmacology and rector of the University of Ghent.

Early Life and Education

Heymans received his secondary education in Turnhout and Ghent. His medical studies at the University of Ghent were interrupted by the First World War, during which he served as an officer in the Belgian Army artillery. He was awarded the Belgian Military Cross, Civil Cross, Fire Cross with 8 buckles, and the French Military Cross during his years of service. After the war ended in 1919, Heymans resumed his medical education and earned his doctorate in medicine from the University of Ghent two years later.

Research and Discoveries

In 1922, Heymans was appointed as a lecturer in pharmacology at the University of Ghent. He then spent the rest of the decade as a research fellow in Paris, Lausanne (Switzerland), Vienna, London, and Western Reserve University (now Case Western Reserve) in Cleveland. In his laboratory at the J.F. Heymans Institute of Pharmacology and Therapy (named after his father), he and his colleagues conducted complex experiments on the pathophysiology of the cardiovascular and respiratory systems. They focused on the influence of the reflexes of the first system on heart rate and rhythm, arterial pressure, and respiratory rate.

Heymans and his father developed experimental methods for isolating nerve fibers and studying the neural reflexes involved in the regulation of the respiratory and cardiovascular systems. They used two anesthetized dogs, one as a donor and the other as a recipient. The blood circulation in the recipient dog's head was isolated from the circulation in the chest organs, abdominal cavity, and limbs. Plastic tubes connected the carotid arteries of the donor and recipient dogs, allowing blood to be supplied to the recipient's head from the donor and drained back to the donor's jugular veins from the recipient's head. The nerve fibers between the recipient's head and body were either left intact or selectively severed, depending on the specific task.

Heymans' research challenged the prevailing beliefs that the cardiovascular and respiratory centers in the medulla oblongata (lower part of the brainstem) regulate blood flow rate, arterial pressure, and blood gas concentration according to the body's immediate physiological needs, without involvement of the reflexes of the nervous system. His experiments from 1924 to 1927 demonstrated that the respiratory rate is regulated by neural reflexes transmitted through the vagus and depressor nerves. The vagus nerve, part of the cranial nerve X, innervates the organs of the neck, chest, and abdominal cavity and is associated with the autonomic nervous system. The depressor nerve is formed by afferent fibers originating from the baroreceptors of the aortic arch.

Further research by Heymans revealed the existence of neural reflexes between the carotid sinus and the vasomotor and respiratory centers in the medulla oblongata. The carotid sinus consists of a network of specialized cells, nerves, and blood vessels in the wall of the carotid artery near its bifurcation into the internal and external branches. Heymans and his father discovered that the carotid sinus contains receptors sensitive to changes in arterial pressure (baroreceptors). When arterial pressure rises, the frequency of nerve impulses from the carotid sinus receptors to the vasomotor and respiratory centers in the medulla oblongata increases, leading to a decrease in respiratory rate, heart rate, and arterial pressure. Conversely, when pressure drops, the frequency of nerve impulses from the baroreceptors to the medullary centers decreases, resulting in an increase in respiratory rate, heart rate, and arterial pressure.

Heymans also explored the role of chemical receptors (chemoreceptors) in the carotid sinus and aortic zones, which are structurally similar to baroreceptors. He and his colleagues demonstrated that the concentrations of both respiratory gases and hydrogen ions are maintained in equilibrium through neural reflexes involving the vascular chemoreceptors, the respiratory center in the medulla oblongata, and the lungs. They observed that when the partial pressure of oxygen decreases, the partial pressure of carbon dioxide increases, and when the concentration of hydrogen ions decreases, nerve impulses from the vascular chemoreceptors to the medulla oblongata reflexively stimulate respiratory rate. Conversely, when the opposite occurs, nerve impulses from the chemoreceptors to the medulla oblongata reflexively inhibit respiratory rate. This allows for the correction of deviations in blood gas concentrations and acid-base balance.

Nobel Prize and Later Years

In 1939, Heymans was awarded the Nobel Prize in Physiology or Medicine "for the discovery of the role played by the sinus and aortic mechanisms in the regulation of respiration." In his Nobel lecture, he challenged the traditional theory that changes in arterial pressure directly affect the respiratory center in the medulla oblongata or the blood flow rate in the brain. Heymans served as the rector of the University of Ghent and the Heymans Institute from 1925. He was passionate about literature, art history, and medicine.

Heymans received numerous awards and honors throughout his career, including the Alvarengen de Piauhy Prize from the Royal Medical Academy of Belgium (1931), the Theophile Gluge Prize from the Royal Academy of Sciences of Belgium (1931), the Belgian Government Medicine Prize awarded every five years (1931), the Montyon Prize in Physiology from the French Academy of Sciences (1934), the Pope Pius XI Prize from the Pontifical Academy of Sciences (1938), and the Burghy Prize from the University of Bern. Heymans was an honorary member of the Royal Society of London, the French Academy of Sciences, the Medical Academy of Paris, and the New York Academy of Sciences.

Heymans married Berte May, a physician, in 1921. They had two sons and two daughters. He edited and published the journal "Archives Internationales de Pharmacodynamic et de Therapie" (International Archives of Pharmacodynamics and Therapy), which was founded by his father in 1895. Heymans passed away in 1968, leaving behind a legacy of groundbreaking discoveries in respiratory and cardiovascular physiology.