Vascular 4 _2024_Benmerzouga.pptx

Vascular 4- Pre-class PowerPoint Imaan Benmerzouga, Ph.D. March 15 2024 3:00-5:00 PM Master of Science in Foundational and Integrated Medical Sciences Program Spring 2024 Learning Objectives Vascular 4 1. Understand the regulation of blood pressure by the renin-angiotensinaldosterone system 2. Defin...

Vascular 4- Pre-class PowerPoint Imaan Benmerzouga, Ph.D. March 15 2024 3:00-5:00 PM Master of Science in Foundational and Integrated Medical Sciences Program Spring 2024 Learning Objectives Vascular 4 1. Understand the regulation of blood pressure by the renin-angiotensinaldosterone system 2. Define ADH (Vasopressin), ANP (Atrial Natriuretic Peptide) and BNP (Brain Natriuretic Peptide including their roles in the regulation of blood pressure 3. Discuss venous pressures and how vascular function curves are regulated 4. Discuss high capacitance in veins and its contribution to venous return 5. Explain the cardiac and vascular function curves Need to know concepts: 1- How does RAAS regulate blood pressure 2- Role of ADH, ANP and BNP is BP regulation 3- What is a vascular function curve vs. cardiac function curve 4- How do the curves interact to have one point of operation Natriuretic Peptides  Downstream effect: promote smooth muscle cell relaxation, diuresis and natriuresis (depending on target tissues)  Counter regulatory hormones and useful diagnostic markers Main physiological effect comes from the NP receptor type A, the predominant receptor on blood vessels Heart Failure Clinics, 2018-01-01, Volume 14, Issue 1, Pages 13-25, Copyright © 2017 Natriuretic Peptides: Atrial Natriuritic Pepetide (ANP) Natriuretic Peptides: Brain Natriuretic Peptide (BNP) Venous return (VR) and Cardiac Output (CO)? Pulmonar y Circulation VR = CO Right Ventricle Venous Return Left Ventricle Systemic Circulation Cardiac Output The cardiac and vascular function curves, what is the difference? Cardiac Function Curve Vascular function curve Review: Pressure gradient Blood flows from region of high pressure  low pressure Systemic venous system 64% Systemic Arterial system 13% Capillaries 7% Pulmonary circuit 9 Heart 7 rie s % of Total Blood volume Ca pil la P Arteries Structure Veins Right Atrium P What is Mean circulatory Pressure (MCP) or also called Mean systemic filling pressure (MSFP) Theoretical pressure that would exist if the heart pump is turned off and blood is allowed to distribute throughout vasculature until pressure is equal throughout When venous return or cardiac output = 0 Medical Physiology, Chapter 23, 533-555.e1 Changes in vascular function curve Panel A shows the effects of changes in cardiac output on right atrial pressure (PRA) and mean circulatory filling pressures (Pmc). Changes in blood volume (Vol) and venous compliance (Cv) cause parallel shifts in the curves and changing Pmc. Panel B shows how changes in systemic vascular resistance (SVR) alter the slope of the systemic function curves without changing Pmc. MSFP only changes with Change in Venous compliance or capacitance Change in blood volume Cardiovascular Physiology Concepts, 3e Right Atrial Pressure (RAP)  Pressure in the right atrium  Typically low fluctuating only several mmHg around a mean of 0 mmHg  RAP is slightly lower than central venous pressure (CVP)  Required for pressure gradient to drive venous return (VR), generally does not exceed 10 mmHg  Difference between CVP and RAP is the driving pressure for blood into the atrium ( P = CVP-RAP) Venous Return Right atrium Vena Cava 6 mmHg 0 mmHg ↑ in RAP will cause ↓ VR ↓ in RAP will cause ↑ in VR Key Concept  VR determines RAP  At the same time RAP determines VR VR RAP Matching of CO with VR VR= CO only at a single point (steady state) Medical Physiology, Chapter 23, 533-555.e1 Permeant Increase in blood volume (BV) Shifts the Match between CO and VR Medical Physiology, Chapter 23, 533-555.e1 Increase in Contractility Shifts the Match between CO and VR Medical Physiology, Chapter 23, 533-555.e1 Summary  The RAAS is the system for long-term regulation of blood pressure though its influence on the vasculature, the kidneys and the heart  Vascular function curve is the curve that shows the relationship between venous return and right atrial pressure (how much is coming into the heart)  Cardiac function curve is the curve that shows the relationship between cardiac output and right atrial pressure (how much is leaving the heart)  At steady state, venous return = cardiac output  MSFP is the theoretical pressure that would exist if the heart pump is turned off and pressure equilibrates throughout the vasculature  VR is determined by the pressure gradient between CVP and RAP Resources Book Chapter: Boron and Boulpaep, Medical Physiology 3e, Ch. 23 https://www-clinicalkey-com.ezproxylocal.library.nova.edu/#!/content/book/3-s2.0-B97 81455743773000239 YouTube Video The RRAS: https://www.youtube.com/watch?v=ibjodC7Ft7U Cardiac Output and Venous Return: https://www.youtube.com/watch?v=WLzinspDoh0&t=2s Lectorio videos in your syllabus