EFFECT OF OXYGEN ON THE AUTOREGULATION OF BLOOD FLOW IN SKELETAL MUSCLE

Persistent Link:
http://hdl.handle.net/10150/281949
Title:
EFFECT OF OXYGEN ON THE AUTOREGULATION OF BLOOD FLOW IN SKELETAL MUSCLE
Author:
Sullivan, Sharon Marie
Issue Date:
1980
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The arterioles of the cat sartorius muscle dilate when arterial pressure is reduced. It has been suggested that this dilation is due to a decrease in blood flow which in turn decreases oxygen delivery and increases tissue production of vasodilator substances. The latter diffuse into the vicinity of the arterioles and cause vascular relaxation. This vascular dilation acts to maintain blood flow through the tissue near the control level at a time when perfusion pressure is reduced. This phenomenon, called autoregulation of blood flow, has been observed in most organs of the body. In the following experiments, we attempted to test the hypothesis that a fall in the oxygen level of the tissue is responsible for blood flow autoregulation. We did this by studying the response of cat sartorius arterioles to arterial pressure reduction under conditions where the muscle was supplied with oxygen from the environment in addition to that normally supplied by the blood. Tissue PO₂ was altered by placing the isolated, auto-perfused cat sartorius muscle in contact with silicone fluid equilibrated with a 0% to 20% oxygen gas mixture. As oxygen tension in the bathing fluid was increased, the preponderant response was a decrease in arteriolar diameter, blood velocity and arteriolar volume flow. To illustrate, 8% of the arterioles constricted by an average of 10% and 18% when the muscle was exposed to oxygen tensions of 66 and 132 mmHg, respectively. When blood flow autoregulation was investigated, it was found that elevated oxygen tension in the bathing fluid abolished any significant arteriolar dilation or flow autoregulation in the majority of arterioles studied. In addition, the elevated oxygen environment caused complete cessation of blood flow in many of the smaller arterioles (< 15μ in diameter). The results of this study strongly suggest that the O₂ level of the tissue is an important determinant in local blood flow regulation.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Blood flow.; Muscles -- Blood-vessels.; Blood -- Analysis.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Physiology
Degree Grantor:
University of Arizona
Advisor:
Johnson, Paul C.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleEFFECT OF OXYGEN ON THE AUTOREGULATION OF BLOOD FLOW IN SKELETAL MUSCLEen_US
dc.creatorSullivan, Sharon Marieen_US
dc.contributor.authorSullivan, Sharon Marieen_US
dc.date.issued1980en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe arterioles of the cat sartorius muscle dilate when arterial pressure is reduced. It has been suggested that this dilation is due to a decrease in blood flow which in turn decreases oxygen delivery and increases tissue production of vasodilator substances. The latter diffuse into the vicinity of the arterioles and cause vascular relaxation. This vascular dilation acts to maintain blood flow through the tissue near the control level at a time when perfusion pressure is reduced. This phenomenon, called autoregulation of blood flow, has been observed in most organs of the body. In the following experiments, we attempted to test the hypothesis that a fall in the oxygen level of the tissue is responsible for blood flow autoregulation. We did this by studying the response of cat sartorius arterioles to arterial pressure reduction under conditions where the muscle was supplied with oxygen from the environment in addition to that normally supplied by the blood. Tissue PO₂ was altered by placing the isolated, auto-perfused cat sartorius muscle in contact with silicone fluid equilibrated with a 0% to 20% oxygen gas mixture. As oxygen tension in the bathing fluid was increased, the preponderant response was a decrease in arteriolar diameter, blood velocity and arteriolar volume flow. To illustrate, 8% of the arterioles constricted by an average of 10% and 18% when the muscle was exposed to oxygen tensions of 66 and 132 mmHg, respectively. When blood flow autoregulation was investigated, it was found that elevated oxygen tension in the bathing fluid abolished any significant arteriolar dilation or flow autoregulation in the majority of arterioles studied. In addition, the elevated oxygen environment caused complete cessation of blood flow in many of the smaller arterioles (< 15μ in diameter). The results of this study strongly suggest that the O₂ level of the tissue is an important determinant in local blood flow regulation.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectBlood flow.en_US
dc.subjectMuscles -- Blood-vessels.en_US
dc.subjectBlood -- Analysis.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplinePhysiologyen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorJohnson, Paul C.en_US
dc.identifier.proquest8017765en_US
dc.identifier.oclc7525136en_US
dc.identifier.bibrecord.b13417782en_US
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