Björn Folkow ( ; 13 October 1921 - 23 July 2012) was a Swedish

physiologist Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a subdiscipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out chemical and ...

. He was professor in

physiology Physiology (; ) is the science, scientific study of function (biology), functions and mechanism (biology), mechanisms in a life, living system. As a branches of science, subdiscipline of biology, physiology focuses on how organisms, organ syst ...

at the

University of Gothenburg The University of Gothenburg () is a List of universities in Sweden, university in Sweden's second largest city, Gothenburg. Founded in 1891, the university is the third-oldest of the current List of universities in Sweden#Public universities, S ...

between 1961 and 1987 and a member of the

Royal Swedish Academy of Sciences The Royal Swedish Academy of Sciences () is one of the Swedish Royal Academies, royal academies of Sweden. Founded on 2 June 1739, it is an independent, non-governmental scientific organization that takes special responsibility for promoting nat ...

Biography

Björn Folkow was born in

Halmstad Halmstad () is a port, university, industrial and recreational urban areas of Sweden, city at the mouth of the Nissan (river), Nissan river, in the provinces of Sweden, province of Halland on the Sweden, Swedish west coast. Halmstad is the seat ...

Sweden Sweden, formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic count ...

. He studied medicine at

Lund University Lund University () is a Public university, public research university in Sweden and one of Northern Europe's oldest universities. The university is located in the city of Lund in the Swedish province of Scania. The university was officially foun ...

where he continued with doctoral studies in

. He defended his thesis on 9 May 1949. Soon thereafter he became associate professor ('laborator') at the new Department of Physiology at the

. He became full professor in 1961 and remained there until his retirement in 1987. Even after retirement he continued being active in the department until shortly before his death in 2012. Folkow was a member of the

and member of the Danish and

Russian Russian(s) may refer to: *Russians (), an ethnic group of the East Slavic peoples, primarily living in Russia and neighboring countries *A citizen of Russia *Russian language, the most widely spoken of the Slavic languages *''The Russians'', a b ...

Academies of Sciences. The European Society of Hypertension established the Björn Folkow Award and Lecture in 1989.

Scientific activity

Folkow published more than 400 scientific papers, covering most areas of cardiovascular physiology. He was an international authority in the field of

high blood pressure Hypertension, also known as high blood pressure, is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms itself. It is, however, a major ri ...

. His main contributions arguably are found in the following areas: * The

myogenic response The myogenic mechanism is how arteries and arterioles react to an increase or decrease of blood pressure to keep the blood flow constant within the blood vessel. Myogenic response refers to a contraction initiated by the myocyte itself instead of ...

of blood vessels. In 1902

Bayliss Bayliss is a surname. Notable people with the surname include: * Adam Bayliss, film producer * Alfred Bayliss, American educational administrator * Brendan Bayliss, musician * David Bayliss, footballer * Edward Bayliss, cricketer * George Bayliss, ...

described that many blood vessels respond to an elevation of transmural pressure by constriction, finally reaching a diameter that is smaller than the initial diameter at the lower pressure. This observation, which had not received much attention at the time, was studied by Folkow as part of his thesis work and subsequently for more than a decade. He described this mechanism as an essential element in vascular control. This is now well-established knowledge in cardiovascular physiology. * The structural adaptation of blood vessels to elevated blood pressure. Folkow and coworkers studied the blood flow in the forearm in persons with high blood pressure, finding an elevated resistance to flow even in situations when the blood vessels would be fully dilated. This indicated a structural adaptation of the blood vessels to a state with smaller lumen diameter but thicker wall (what now is termed remodelling). This confers to the vessel wall what corresponds to a longer lever, enabling them to contract against higher pressures. This can be seen as the beginning of a vicious circle, where an elevation of pressure causes remodelling that promotes further pressure elevation. Folkow's description of these vascular alterations has since been verified in a large number of studies. * The role of the central nervous system in cardiovascular control. Possibly as a consequence of Folkow's interest in the interplay between body and mind he became interested in central nervous control of the cardiovascular system. He particularly pointed to the role of the defence-alarm reaction (the

fight-or-flight response The fight-or-flight or the fight-flight-freeze-or-fawn (also called hyperarousal or the acute stress response) is a physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival. It was first describ ...

) in everyday blood-pressure control. His opinion was that individuals with a tendency to react more strongly with this response tend to develop higher blood pressure, since they more often get blood pressure elevation in response to common stressors. Even though the kidney is important for blood pressure control, he viewed it as subordinate to the brain. * The function of the sympathetic nerve terminals. The

sympathetic nervous system The sympathetic nervous system (SNS or SANS, sympathetic autonomic nervous system, to differentiate it from the somatic nervous system) is one of the three divisions of the autonomic nervous system, the others being the parasympathetic nervous sy ...

has a central role in blood pressure control. It thus attracted Folkow's attention early on, in particular following the mapping of this system. Combining quantification of the density of adrenergic varicosities in the vascular wall with estimates of noradrenaline release indicated that on average only a few per cent of the transmitter content of a

synaptic vesicle In a neuron, synaptic vesicles (or neurotransmitter vesicles) store various neurotransmitters that are exocytosis, released at the chemical synapse, synapse. The release is regulated by a voltage-dependent calcium channel. Vesicle (biology), Ves ...

was released from a given nerve terminal by an

action potential An action potential (also known as a nerve impulse or "spike" when in a neuron) is a series of quick changes in voltage across a cell membrane. An action potential occurs when the membrane potential of a specific Cell (biology), cell rapidly ri ...

in the nerve. It has since been found that transmitter release from a varicosity is intermittent, but whether all or only part of the vesicle's contents is released is still a matter of debate. * The physiology of aging. Partly because of his contacts with the professor of geriatrics in Gothenburg, Alvar Svanborg, Folkow acquired an interest for the implications of physiological aging in cardiovascular control. This collaboration resulted in a major review article in this field.

Textbook

* Circulation This textbook was written by Folkow in collaboration with Eric Neil. It is a thorough description of the essential concepts in this area, and large parts of it remain relevant even today, although for obvious reasons more modern aspects are lacking. A follow-up was planned in the eighties in collaboration with Paul Korner, but due to differences in opinion on several aspects Folkow withdrew from the collaboration to save their friendship.

References

{{DEFAULTSORT:Folkow, Björn Swedish physiologists 1921 births 2012 deaths Academic staff of the University of Gothenburg Members of the Royal Swedish Academy of Sciences