BLOOD FLOW IN ARISTOTLE

2020 ◽  
Vol 70 (1) ◽  
pp. 137-153
Author(s):  
Claire Bubb

Modern readers view ancient theories of blood flow through the lens of circulation. Since the nineteenth century, scholarly work on the ancient understanding of the vascular system has run the gamut from attempting to prove that an ancient author had in fact, to some extent or another, pre-empted Harvey's discovery of the circulation of the blood or towards attempting, often with some empathetic embarrassment, to explain the failure on the part of an ancient author to notice something that seems so obvious to the modern eye. Thus C.R.S. Harris's 1973 book The Heart and Vascular System in Ancient Greek Medicine, which remains the standard on the topic, opens with a sentence in which he marvels at how the otherwise admirable ancient Greek physicians could have ‘failed entirely to arrive at any conception of the circulation of the blood’. This modern vantage point has had an unfortunate effect. In the case of Aristotle in particular, understanding of his cardiovascular system has been diminished by a tendency to define it in contradistinction to our own modern understanding of circulation. By deliberately uncoupling from the framework of modern physiology, this paper will offer a richer and more accurate picture of his views.

2020 ◽  
Vol 44 (2) ◽  
pp. 163-168 ◽  
Author(s):  
Shannon E. Washburn ◽  
Randolph H. Stewart

Blood flow through the cardiovascular system is governed by the same physical rules that govern the flow of water through domestic plumbing. Using this analogy in a teaching laboratory, a model of the cardiovascular system constructed of pumps and pipes was used to demonstrate the basic interactions of pressure, flow, and resistance in a regulated system, with student volunteers providing the operational actions and regulatory components. The model was used to validate predictions and explore solutions prompted by student discussion. This interactive teaching laboratory provides an engaging experiential exercise that demonstrates regulation of flow and pressure in an intact cardiovascular system with apposite changes in heart rate and resistance. In addition, the system provides strong clinical correlates and illustrates how that regulated system responds to challenges such as heart failure, inappropriate vasodilation, and hemorrhage. The results demonstrate that, with limited practice, the instructor can effectively guide the students to reliably reproduce physiologically appropriate results.


1975 ◽  
Vol 69 (2) ◽  
pp. 143
Author(s):  
Robert J. Littman ◽  
C. R. S. Harris

Author(s):  
Md Zeeshan ◽  
Deshbandhu Joshi

The cardiovascular system refers to the heart, blood vessels and the blood. Blood contains oxygen and other nutrients which your body needs to survive. The body takes these essential nutrients from the blood. Angiography is an imaging test that uses X-rays to view your body's blood vessels. The X-rays provided by an angiography are called angiograms. This test is used to study narrow, blocked, enlarged, or malformed arteries or veins in many parts of your body, including your brain, heart, abdomen, and legs. Angioplasty is a procedure to restore blood flow through the artery. You have angioplasty in a hospital. The doctor threads a thin tube through a blood vessel in the arm or groin up to the involved site in the artery. The tube has a tiny balloon on the end. Cardiovascular disease generally refers to conditions that involve narrowed or blocked blood vessels that can lead to a heart attack, chest pain (angina) or stroke. Other heart conditions, such as those that affect your heart's muscle, valves or rhythm, also are considered forms of heart disease. Keyword: cardiovascular system, angiography, angioplasty


1978 ◽  
Vol 19 (2) ◽  
pp. 271-280 ◽  
Author(s):  
Hideomi FUJIWARA ◽  
Koichi TANIGUCHI ◽  
Tomohiro IIZUMI ◽  
Akihiro NIWA ◽  
Takashi YAMADA ◽  
...  

1949 ◽  
Vol s3-90 (9) ◽  
pp. 13-25
Author(s):  
D. A. PARRY

1. The gross morphology, micro-anatomy, and histology of the blubber of the porpoise (Phocaena phocaena) and the rorquals (Balaenoptera spp.) are described. 2. If the surface area is given by Kl2, l being the overall length, then K is 0.39 in Phocaena and 0.35 in Balaenoptera, excluding fins and flukes. 3. Blubber consists of the whale's epidermis, dermis, and hypodermis. The hypodermis is relatively very thick and almost exclusively fatty, and in the species studied merges into the dermis which is mostly composed of white fibres. It extends into the epidermis as ‘dermal ridges’, from which the papillae arise. In the epidermis can be recognized: stratum germinativum, divided into the deep cylindrical cells and the more superficial prickle cells; and stratum corneum. 4. The vascular system is composed of arterioles running up to the base of the epidermis, giving rise to twigs which run up the dermal ridges to supply the capillaries in the papillae; and venules collecting twigs from the ridges and running down through dermis and hypodermis, connecting in the dermis with a venous plexus. Small ‘accompanying venules’ run with the arterioles to the base of the epidermis. 5. The conductivity of blubber is 0.00050 gm.-cal./sq. cm./°C./cm. and the deep body temperature is about 36° C. Thus in temperate and polar waters most whales lose heat at a greater rate than the basal metabolic rate of land homotherms, even when the blood-flow through the blubber is negligible. It is suggested that whales need to keep swimming in order to keep warm. 6. The vascular system in the blubber provides a mechanism for regulating heat loss. 7. It is shown that the energy liberated by the reduction in blubber thickness suffered by rorquals in the southern hemisphere during the winter is sufficient to meet at least a significant part of their total needs.


Over the past few decades, stroke has become one of the most common cause deaths. The heart muscle, like every other organ or tissue in our body, needs oxygen-rich blood to survive. Coronary artery disease means narrowing of the coronary arteries. This narrowing is due to a buildup of plaque in the walls of the arteries. Computational simulations provide invaluable information that is extremely difficult to obtain experimentally and is one of the many CFD sample applications in the biomedical area in which blood flow through an abnormal artery can be predicted. CFD analysis is increasingly performed to study fluid phenomena inside the human vascular system. In this paper, the study is to develop 3D CFD model of the Coronary artery to observe the blood flow through artery and estimate some of the hemodynamic parameters of blood during systolic and diastolic phase with plaque formation in artery. Hemodynamic parameters were quantified and flow patterns are visualized in the presence of plaques by using CFD.


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