Cerebral and peripheral vascular responses to hypercapnia
department or school: Health and Social Development, Faculty of (Okanagan)
department or school: Health and Exercise Sciences, School of (Okanagan)
data provider: DSpace
degree campus: UBCO
creator: Carr, Jordan Mark John Ramone
issued: 2022-08-25T19:50:05Z
issued: 2022
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: During hypercapnia (elevated partial pressure of arterial CO₂; PaCO₂) cerebral blood flow (CBF) is elevated in order to maintain pH in the cerebral tissues; mean arterial pressure (MAP), minute ventilation (Vᴇ), and heart rate also increase. The shearing force caused by blood flowing through arteries also influences haemodynamics in the vasculature throughout the body, in a regionally varied manner. These PaCO₂, MAP, and shear stress-mediated responses are becoming relatively well understood, though the integration of such responses in both cerebral and peripheral vasculatures simultaneously has mostly been ignored. As hypercapnia causes both cerebral and systemic effects, which are inextricably connected, this thesis compared and contrasted hypercapnic-mediated responses between the cerebral and peripheral vasculatures, with recourse to the various influences of shear stress, MAP, and Vᴇ. Study one examined vascular responses to shear stress in cerebral and peripheral conduit arteries, comparing these against the hypercapnia-mediated response in the cerebral vasculature. The findings revealed that neither brachial artery shear-mediated vasodilation nor CBF reactivity to CO₂ were correlated with cerebral shear-mediated function. In Study two, via retrospective analyses, we assessed the within-test stability of CBF responses to CO₂ using dynamic end-tidal forcing, demonstrating that CBF responses to CO₂ do not fluctuate unless the CO₂ stimulus does. Study three investigated the influence of acute reductions in arterial oxygen (O₂) content on CBF responses to PaCO₂. Here, acute anemia elevated basal CBF which maintained cerebral O₂ delivery and elevated cerebral CO₂ washout. Study 4A assessed the peripheral vascular response to hypercapnia while accounting for the influences of shear stress and sympathetic nervous adrenergic activity (which controls MAP). We found that peripheral vascular responses to hypercapnia are suppressed by adrenergic innervation. Study 4B then…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/82526
note: Cerebral and peripheral vascular responses to hypercapnia by Jordan Mark John Ramone Carr MLitt, University of Aberdeen, 2017 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in The College of Graduate Studies (Kinesiology) THE UNIVERSITY OF BRITISH COLUMBIA (Okanagan) August 2022 © Jordan Mark John Ramone Carr, 2022 ii The following individuals certify that they have read, and recommend to the College of Graduate Studies for acceptance, a thesis/dissertation entitled: Cerebral and peripheral vascular responses to hypercapnia submitted by Jordan Mark John Ramone Carr in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Kinesiology Dr Phil Ainslie, School of Health and Exercise Sciences Supervisor Dr Chris McNeil, School of Health and Exercise Sciences Supervisory Committee Member Dr Greg DuManoir, School of Health and Exercise Sciences Supervisory Committee Member Dr Chris West, School of Kinesiology, UBC Vancouver University Examiner Dr James Duffin, University of Toronto External Examiner iii Abstract During hypercapnia (elevated partial pressure of arterial CO2; PaCO2) cerebral blood flow (CBF) is elevated in order to maintain pH in the cerebral tissues; mean arterial pressure (MAP), minute ventilation (V̇E), and heart rate also increase. The shearing force caused by blood flowing through arteries also influences haemodynamics in the vasculature throughout the body, in a regionally varied manner. These PaCO2, MAP, and shear stress-mediated responses are becoming relatively well understood, though the integration of such responses in both cerebral and peripheral vasculatures simultaneously has mostly been ignored. As hypercapnia causes both cerebral and systemic effects, which are inextricably connected, this thesis compared and contrasted hypercapnic-mediated responses between the cerebral and peripheral vasculatures, with recourse to the various influences of shear stress, MAP, a…
has type: Thesis/Dissertation
date issued: 2022-09
is shown at: 10.14288/1.0417552
language: eng
degree discipline: Kinesiology
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Ainslie, Philip N., 1974-
type: Text
identifier URI: http://hdl.handle.net/2429/82526