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Thesis
The role of the hydrostatic indifferent point in governing splachnic blood pooling during orthostatic stress
University of Iowa
Master of Science (MS), University of Iowa
Spring 2011
DOI: 10.17077/etd.ktci6os1
Abstract
<p>The response of the circulatory system to gravity and hydrostatic forces has been well studied, for example the hydrostatic indifferent point (the location at which pressure does not change with posture) of the venous system has been established to be an important determinant of orthostatic responses and it has been found to be located near the diaphragm. However, the role of the abdomen has been less researched; for example, it appears that the concept that the abdominal compartment may have its own hydrostatic indifferent point has been overlooked. The goal of the present study was to establish the location of the abdominal hydrostatic indifferent point (HIPab) and to test the hypothesis that binding of the lower abdomen would shift the location of the HIPab cranially. Intra-abdominal pressure was measured using a modified wick needle technique in the supine and upright posture before and after binding of the lower abdomen in 7 anesthetized rats. In the unbound condition, the HIPab was located 5.2 ± 0.3 cm caudal to the xyphoid, meaning the hepatic veins were exposed to relatively large negative interstitial pressures during head-up tilt. Binding of the lower abdomen significantly (p <0.05) shifted the HIPab cranially by 1.7 cm. Thus, the relatively caudal location of the HIPab causes a relatively large hepatic transmural pressure owing to the fall in interstitial pressure during upright posture. The cranial shift of the HIPab by binding of the lower abdomen lessens the fall in hepatic extramural pressure and thereby protects the hepatic veins from distension.</p>
Details
- Title: Subtitle
- The role of the hydrostatic indifferent point in governing splachnic blood pooling during orthostatic stress
- Creators
- Ursula Anne Diehl - University of Iowa
- Contributors
- Don D. Sheriff (Advisor)Kevin C. Kregel (Committee Member)Harald M. Stauss (Committee Member)
- Resource Type
- Thesis
- Degree Awarded
- Master of Science (MS), University of Iowa
- Degree in
- Exercise Science
- Date degree season
- Spring 2011
- Publisher
- University of Iowa
- DOI
- 10.17077/etd.ktci6os1
- Number of pages
- viii, 46 pages
- Copyright
- Copyright 2011 Ursula Anne Diehl
- Language
- English
- Description bibliographic
- Includes bibliographical references (pages 44-46).
- Academic Unit
- Health and Human Physiology
- Record Identifier
- 9983776802102771
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