Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Dee Unglaub Silverthorn, Ph.D. H UMAN P HYSIOLOGY PowerPoint ® Lecture Slide Presentation by Dr. Howard D. Booth, Professor of Biology, Eastern Michigan University AN INTEGRATED APPROACH T H I R D E D I T I O N Chapter 15 Blood Flow and the Control of Blood Pressure

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings About this Chapter How various blood vessels are constructed and role in circulation Components of "blood pressure", role and measurement Product exchange at the capillary beds Lymph vessels, distribution and role in circulation How blood pressure and circulation are regulated Key components of cardiovascular disease

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Arteries: blood from heart Strong & Elastic Conduct blood to capillaries Sphincters Capillaries: exchange with cells Veins Return blood to heart Valves The Blood Vessels and the Cardiovascular System

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings The Blood Vessels and the Cardiovascular System Figure 15-1: Functional model of the cardiovascular system

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Endothelium Elastic tissues Rebounds Evens flow Smooth muscles Fibrous tissue Tough Resists stretch Make Up of Bllod Vessels: Arteries and Arterioles Figure 15-2: Blood vessels

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Bypass capillaries Large cells Speed flow Metarterioles Figure 15-3: Metarterioles

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Endothelium: one cell thick Continuous Fenestrated Basement membrane Make Up of Blood Vessels: Capillaries

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Make Up of Blood Vessels: Capillaries Figure 15-16: Types of capillaries

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Thinner walls Larger diameter Closer to skin Less muscle Less elastic Make Up of Blood Vessels: Veins and Venules (Contrasted to Arteries) Figure 15-3: Metarterioles

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Normal body maturation and growth Endometrium Endurance training Abnormal growth to service cancerous tissue Wound repair and consequences Failure to regrow in heart tissues after heart attack Failure to regrow in brain after stroke Angiogenesis: Growth of New Blood Vessels

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Pulsatile: surges in arteries Elastic rebound evens & maintains pressure Blood Pressure: Generated by Ventricular Contraction

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Blood Pressure: Generated by Ventricular Contraction Figure 15-4: Elastic recoil in the arteries

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Blood Pressure (BP): Measurements "Blood pressure" Systolic over diastolic About 120/80 mmHg Sphygmomanometer "Estimate of pressure" Korotkoff sounds

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Blood Pressure (BP): Measurements Figure 15-7: Measurement of arterial blood pressure

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Pulse pressure = Systolic–Diastolic Mean arterial pressure (MAP) = Diastolic + 1/3 pulse pressure More Blood Pressures: Pulse and Mean Arterial Pressures

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings More Blood Pressures: Pulse and Mean Arterial Pressures Figure 15-5: Pressure throughout the systemic circulation

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Factors Controlling MAP : The Driving Pressure for Blood Flow Blood volume Cardiac output Resistance Distribution

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Factors Controlling MAP : The Driving Pressure for Blood Flow Figure 15-10: Factors that influence mean arterial pressure

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Arteriole Resistance: Control of Local Blood Flow Figure 15-11: Hyperemia

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Arteriole Resistance: Control of Local Blood Flow Myogenic auto regulation Paracrines: Hyperemia Sympathetic nerves – CNS

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Responds to metabolic need Precapillary sphincters Local & CNS regulators Huge variations (example: skeletal m 20-85%) Distribution of Blood in the Body Organs

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Distribution of Blood in the Body Organs Figure 15-13: Distribution of blood in the body at rest

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Lowest Velocity Hydrostatic pressure drops Capillary Blood Flow: Greatest Total Cross Sectional Area Figure 15-17: The velocity of flow depends on the total cross- sectional area

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Capillary Exchange: Colloidal Osmotic Pressure is Constant Proteins stay in capillary Water, oxygen, glucose – move out CO 2, N wastes, water – move in Bulk flow out on arterial side, in on venous side

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Capillary Exchange: Colloidal Osmotic Pressure is Constant Figure 15-18a: Fluid exchange at the capillary

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Net filtration – net absorption = net out flow About 2 L/day collected by lymph vessels Net Out Flow Into ECF Figure 15-18b: Fluid exchange at the capillary

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings High on arterial side – bulk flow out Low on venous side – bulk flow in Fenestrations &/or leaky joints speed exchange Capillary Exchange: Hydrostatic Pressure Declines Figure 15-18a: Fluid exchange at the capillary

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Lymphatic System: Structure and Roles (overview) Lymphatic structures Capillaries with valves Lymph vessels Lymph nodes & organs Immune defense: lymphocytes Transport of fats Collects excess ECF Returns to plasma Edema

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Lymphatic System: Structure and Roles (overview) Figure 15-19: The lymphatic system

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Lymphatic System: Overview Consists of two semi-independent parts A meandering network of lymphatic vessels Lymphoid tissues and organs scattered throughout the body Returns interstitial fluid and leaked plasma proteins back to the blood Lymph – interstitial fluid once it has entered lymphatic vessels

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 20.2a

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Lymphatic System: Overview Figure 20.1a

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Lymphatic Vessels A one-way system in which lymph flows toward the heart Lymph vessels include: Microscopic, permeable, blind-ended capillaries Lymphatic collecting vessels Trunks and ducts

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Lymphatic Capillaries Similar to blood capillaries, with modifications Remarkably permeable Loosely joined endothelial minivalves Withstand interstitial pressure and remain open The minivalves function as one-way gates that: Allow interstitial fluid to enter lymph capillaries Do not allow lymph to escape from the capillaries

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Lymphatic Capillaries During inflammation, lymph capillaries can absorb: Cell debris Pathogens Cancer cells Cells in the lymph nodes: Cleanse and “examine” this debris Lacteals – specialized lymph capillaries present in intestinal mucosa Absorb digested fat and deliver chyle to the blood

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Lymphatic Trunks Lymph is delivered into one of two large trunks Right lymphatic duct – drains the right upper arm and the right side of the head and thorax Thoracic duct – arises from the cisterna chyli and drains the rest of the body

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Lymphatic Trunks Figure 20.2b

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Lymph Transport The lymphatic system lacks an organ that acts as a pump Vessels are low-pressure conduits Uses the same methods as veins to propel lymph Pulsations of nearby arteries Contractions of smooth muscle in the walls of the lymphatics

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Regulation of Blood Pressure and Heart Rate Medullary cardiac control center (Brainstem) Cardioacceleratory Center Cardioinhibitory Center Baroreceptor reflex Carotid Aortic Kidney: blood volume Hypothalamus & Cortex: stress, blushing, etc.

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Regulation of Blood Pressure Figure 15-22: The baroreceptor reflex: the response to increased blood pressure

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Risk Factors: Smoking Obesity Diabetes Genes Diseases: Hypertension Stroke "Heart Attack" Cardiovascular Diseases: #1 killer

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings LDL build up Plaque  Flow Rupture Clot Blocked flow Tissue death Mechanism of Atherosclerosis

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings We now understand that atherosclerosis is a chronic inflammation of arteries, which develops over decades in response to the biologic effects of risk factors. Atherogenesis begins as a qualitative change to intact endothelial cells; when subjected to oxidative, hemodynamic, or biochemical stimuli (from smoking, hypertension, or dyslipidemia) and inflammatory factors, they change their permeability to promote the entry and retention of blood-borne monocytes and cholesterol-containing LDL particles. Inflammation and biochemical modifications ensue, causing endothelial and smooth-muscle cells to proliferate, produce extracellular matrix molecules, and form a fibrous cap over the developing atheromatous plaque. Plaques lead to clinical symptoms by producing flow-limiting stenoses (causing stable angina) or by provoking thrombi that interrupt blood flow on either a temporary basis (causing unstable angina) or a permanent one (causing myocardial infarction). Physical disruption (rupture) of the plaque exposes procoagulant material within the core of the plaque to coagulation proteins and platelets, triggering clotting. How Atherosclerosis Develops

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Mechanism of Atherosclerosis Figure 15-24: The development of atherosclerotic plaques

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Mechanism of Atherosclerosis Figure 15-24: The development of atherosclerotic plaques

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Blood vessels, anatomy & role in circulation Measuring blood pressures, MAP & pulse pressure Role of resistance in BP and distribution of blood Autoregulation, baroreceptros, medullary cardiac control center and CNS regulation of blood pressure & distribution Summary

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Hydrostatic & colloidal osmotic pressures direct bulk flow in capillary exchange by diffusion, fenestrations & leaky joints Role of lymphatic system to return excess ECF to plasma Atherosclerosis common to several cardiovascular diseases Summary