Blood Vessels Structure and Function PDF

MEDI11-102 Week 2 Title Blood vessels: Structure and function Presenter Assistant Professor Joan Roehl In...

MEDI11-102 Week 2 Title Blood vessels: Structure and function Presenter Assistant Professor Joan Roehl In this session, you will learn about the composition of blood vessels (three tunics), the micro-anatomy/histology Why you should attend this session of different vessel types, and how their structure relates to their function. What you will need to do in preparation Refresh your knowledge about primary tissues from MEDI11-101 What you will need to bring N/A 12/09/2024 CRICOS Provider Code: 00017B TEQSA: PRV12072 1  ATTENDANCE Have you checked in? Please remember to check into the session via Osler! 12/09/2024 CRICOS Provider Code: 00017B TEQSA: PRV12072 2  Acknowledgement of Country Bond University acknowledges the Kombumerri people, the traditional Owners and Custodians of the land on which the University now stands. We pay respect to Elders past, present and emerging. Copyright Warning. This material has been reproduced and communicated to you by or on behalf of Bond University in accordance with section 113P of the Copyright Act 1968 (Act). The material in this communication may be subject to copyright under the Act. Any further reproduction or communication of this material by you may be the subject of copyright protection under the Act. 12/09/2024 CRICOS Provider Code: 00017B TEQSA: PRV12072 3  Blood vessels: Structure and function Assistant Professor Joan Roehl 12/09/2024 CRICOS Provider Code: 00017B TEQSA: PRV12072 4  Weekly Learning Outcomes Week 2, SS01  Describe the basic structure of blood vessels and relate this to their key function 12/09/2024 CRICOS Provider Code: 00017B TEQSA: PRV12072 5  Session Learning Outcomes During this session you will learn about  Overall structure/architecture of blood vessels (3 tunics/layers); heart (briefly)  Micro-anatomy of different vessel types, including lymphatic vessels: Structure and function 12/09/2024 CRICOS Provider Code: 00017B TEQSA: PRV12072 6 Introduction: An overview of the Circulatory System Lymphatic system Cardiovascular System Lymphatic vessels Heart (week 3) Lymph nodes & tissues Blood (week 1) (week 5) Blood vessels (week 2) Composition: Intima (endothelium) Media (smooth muscle) Adventitia (connective Inter-relationship between tissue) the two systems Types: Arteries Capillaries Veins Sobotta Atlas of Anatomy, Volume 1 CRICOS Provider Code: 00017B TEQSA: PRV12072 Paulsen, Friedrich 7 Published January 1, 2023. Pages 1-80. © 2023.  Blood vessels – Composition (tunics) Histologically, blood vessels consist of concentric layers or tunics of different tissue types. Tunica intima/interna (inner layer) Very thin lining of endothelium Tunica adventitia/externa (outer layer) (simple squamous epithelium) + Fibrous connective tissue (continuous with thin layer of supporting connective stromal connective tissue) tissue (loose CT below basement membrane) collagen + elastic fibres Note: Typically, only the nuclei are noticeable. Lumen Tunica media (middle layer) (often the thickest layer) Nerve tissue inconspicuous Smooth muscle (arranged circumferentially) - regulates smooth muscle and elastic fibres in varying - mediates pain sensation proportions CRICOS Provider Code: 00017B TEQSA: PRV12072 Image © Blue Histology 8 https://histology.siu.edu/crr/cvguide.htm CRICOS Provider Code: 00017B TEQSA: PRV12072 https://histology.medicine.umich.edu/res ources/cardiovascular-system Blood vessels - Types Blood vessels are categorised by function. The composition of the wall varies quantitatively HEART among these subcategories. Arteries (conduct blood away from the heart) Elastic (conducting) arteries  muscular (distributing) arteries  arterioles VEINS Capillaries (communicate between arteries and veins) ARTERIES Transport blood Continuous toward the heart Transport blood away from heart Fenestrated **microvasculature: site of exchange of Discontinuous gases, nutrients, fluids & metabolic waste** Veins (return blood to the heart) Venule  medium-sized vein  large vein VENULE ARTERIOLE Image courtesy of Dr Nicolene Lottering, CRICOS Provider Code: 00017B TEQSA: PRV12072 CAPILLARIES Bond University, 2023 10 https://mediaplayer.pearsoncmg.com/assets/sci-bio-fw-the-interrelationship-of-cross-sectional-area-of-blood- vessels-blood-flow-velocity-and-blood-pressure A AORTA Area of greatest velocity, volume and blood pressure, as it leaves the left ventricle of the heart E 3 major collateral E ELASTIC ARTERIES branches of aortic arch Arteries which “conduct” blood to A specific anatomical regions Major collateral or terminal vessels (that come off and include the aorta) E descends as Function to maintain constant abdominal aorta pressure gradient despite pumping action Pulmonary trunk Brachiocephalic Trunk M Subclavian a. Carotid a. Common iliac a. M MUSULAR ARTERIES ‘Distribute’ blood to muscles or organs Named after what they supply M Contain mostly smooth muscle in wall Under mostly sympathetic M regulation Renal arteries Brachial a. Radial a. Femoral a. Popliteal a. HEART RATE VARIABILITY : LINEAR AND NONLINEAR ANALYSIS WITH APPLICATIONS IN HUMAN PHYSIOLOGY - Scientific Figure on Campbell Biology, 12th edition ResearchGate. Available from: https://www.researchgate.net/figure/A- Published by Pearson CRICOS©Provider 2021 Code: 00017B TEQSA: PRV12072 schematic-overview-of-the-cardiovascular-system-with-the-heart-as- 11 driving-force-From_fig3_267403305 [accessed 17 Jan, 2024]  VEINS: Structural differences Low pressure system ~ 5-10 mmHg Largest portion of blood volume at rest (64%) located within systemic veins and venules  BLOOD RESERVOIR or CAPACITANCE VESSELS Venae Comitantes Median cubital vein thin folds in the tunica pressure 5mmHg blood returning through veins to the Distal body regions e.g. DEEP veins course with intima that form valve hands/feet, forearm/leg, cusps heart; push against GRAVITY the arteries During exercise or trauma contraction of skeletal muscle companion or SUPERFICIAL veins run Function: aid in venous sympathetic impulses cause  vein compressed, increases accompanying veins (X2) beneath the skin return by preventing venoconstriction of tunica media blood pressure  one way travel with single artery (subcutaneous space) - backflow of blood ↓ volume of blood in reservoirs and valve open Pulsations of the artery aid easy to visualise/access redirects to skeletal muscle/tissue with venous return CRICOS Provider Code: 00017B TEQSA: PRV12072 This slide is courtesy of Dr Nicolene Lottering, Bond University, 2023 CRICOS Provider Code: 00017B TEQSA: PRV12072 © Pearson Education, Inc. 13  Histology: Arteries vs. veins 12/09/2024 CRICOS Provider Code: 00017B TEQSA: PRV12072 14 © 2015 Pearson Education, Inc. 12/09/2024 CRICOS Provider Code: 00017B TEQSA: PRV12072 https://www.columbia.edu/itc/hs/medical/sbpm_histology_2009/lab/lab02_squamous.html 12/09/2024 CRICOS Provider Code: 00017B TEQSA: PRV12072 CRICOS Provider Code: 00017B TEQSA: PRV12072 © Pearson Education, Inc. 18  Elastic or conducting arteries (aorta, its larger branches) Tunica media dominated by elastic tissue – compliance, stretch, recoil – pressure reservoir Tunica media = elastic laminae, collagen + smooth muscle fibres Tunica adventitia = collagen (whitish; refractile), some elastic fibres Small blood vessels © 1999-2024, Rice University. Except where otherwise noted, textbooks on this site are licensed = vasa vasorum CRICOS Provider Code: 00017B TEQSA: PRV12072 19 under a Creative Commons Attribution 4.0 International License. CRICOS Provider Code: 00017B TEQSA: PRV12072 © Pearson Education, Inc. 20  Distributing or muscular arteries (e.g. bra chia l, ra dia l, fe m ora l, cor ona r y – m os t a r t e r ies) Tunica media dominated by smooth muscle – regulation IEM = internal elastic membrane or lamina (IEL) EEM = external elastic membrane or lamina (EEL) S = subendothelium | C = collagen | RBC = red blood cells TM = circumferentially arranged smooth muscle, collagen fibres, © 2015 Pearson Education, Inc. thickest of three tunics; generally thicker than veins of similar size TA = mostly collagen + diffuse external elastic lamina (EEL); CRICOS Provider Code: 00017B TEQSA: PRV12072 continuous with fascia of the organ in which the vessel is found 21 Distributing or muscular arteries (e.g. bra chia l, ra dia l, fe m ora l, cor ona r y – m os t a r t e r ies) Tunica media dominated by smooth muscle – regulation Nerve supply: ANS innervation 𝜶𝜶-receptors on arteries stimulated via epinephrine or norepinephrine ↑ stimulation causes vasoconstriction ↓ stimulation causes vasodilation Damage to vessel → vascular spasm (limits blood loss) © AMBOSS CRICOS Provider Code: 00017B TEQSA: PRV12072 22 CRICOS Provider Code: 00017B TEQSA: PRV12072 © Pearson Education, Inc. 23  Arterioles - im m edia t ely pr eceding a ca pilla r y bed Single-few layers of smooth muscle in tunica media, regulate blood flow to capillaries, provide resistance text CRICOS Provider Code: 00017B TEQSA: PRV12072 24 Source: Wheater's Functional Histology, Published January 1, 2023. Pages 144-158.e5. © 2023. Source: Netter's Essential Physiology, Published January 1, 2016. Pages 130-150. © 2016. CRICOS Provider Code: 00017B TEQSA: PRV12072 https://www.slideshare.net/slideshow/histology-of-blood-vessels/187047892#51 25  Comparison of the walls of an elastic artery, a muscular artery, and an arteriole is shown. In terms of scale, the diameter of an arteriole is measured in micrometers compared to millimeters for elastic and muscular arteries. © 1999-2024, Rice University. 12/09/2024 Except where CRICOS Provider otherwise Code: 00017B noted, TEQSA: textbooks on this site are licensed PRV12072 26 under a Creative Commons Attribution 4.0 International License. CRICOS Provider Code: 00017B TEQSA: PRV12072 © Pearson Education, Inc. 27  Histology Guide © Faculty of Biological Sciences, University of Leeds https://www.histology.leeds.ac.uk/circulatory/capillaries.php Capillaries - smallest (microscopic) vessels Communication between arteries and veins Diameter < 10 µm (RBC in single file) Thin, flattened endothelial cells form endothelium (E) (tend to be inconspicuous, ususually only see nuclei), supported by a basement membrane Wrapped at intervals around capillaries are pericytes (P) - cells with contractile properties that can regulate diameter/capillary blood flow Source: Wheater's Functional Histology, Published January 1, 2023. Pages 144-158.e5. © 2023. CRICOS Provider Code: 00017B TEQSA: PRV12072 28  Capillaries - smallest (microscopic) vessels Three types of capillaries © 1999-2024, Rice University. Except where CRICOS Provider otherwise Code: 00017B noted, TEQSA: textbooks on this site are licensed PRV12072 29 under a Creative Commons Attribution 4.0 International License. Capillaries - smallest (microscopic) vessels Three types of capillaries – continuous capillaries (common) Gases pass through endothelial cells by diffusion Small molecules pass through small gaps between neighbouring cell (except brain) = Intercellular clefts Large molecules by rapid vesicular transcytosis e.g. muscle, lungs, CNS (tight junctions), skin, fat Image © Blue Histology http://lecannabiculteur.free.fr/SITES/UNIV%20W.AUSTRALIA/mb140/Core CRICOS Provider Code: 00017B TEQSA: PRV12072 Pages/Vascular/Vascular.htm#CAPILLARIES 30 Capillaries - smallest (microscopic) vessels Three types of capillaries – fenestrated capillaries Endothelial plasma membrane with pores (fenestrations) More permeable than continuous capillaries; quick exchange of substances e.g. kidneys, intestines, gallbladder, endocrine glands https://histology.siu.edu/crr/RN002b.htm CRICOS Provider Code: 00017B TEQSA: PRV12072 31 Capillaries - smallest (microscopic) vessels Three types of capillaries – sinusoidal/discontinuous (rare) Very large fenestrations + incomplete basement membrane = leaky; exchange of large macromolecules and cells between blood and surrounding tissue More voluminous than capillaries Only in liver, bone marrow, spleen, adrenal medulla CRICOS Provider Code: 00017B TEQSA: PRV12072 A Novel Method of HCC Pathological Images Recognition based on Morphological Distribution of Liver Cell 32 Cords - Scientific Figure on ResearchGate. Available from: https://www.researchgate.net/figure/Schematic-of- liver-cell-cords fig1 308043510 [accessed 17 Jan, 2024]  Capillaries - smallest (microscopic) vessels Histology Guide © Faculty of Biological Sciences, University of Leeds 12/09/2024 CRICOS Provider Code: 00017B TEQSA: PRV12072 33 https://www.histology.leeds.ac.uk/circulatory/capillaries.php CRICOS Provider Code: 00017B TEQSA: PRV12072 © Pearson Education, Inc. 34 Venules Post-capillary venules: endothelium and pericytes Larger venules: endothelium + 1-2 layers of tunica media Easily distinguishable from arterioles by the size of the lumen relative to wall thickness Brian Bich © https://blogs.lsc.edu/brianbich/portfolio-item/m-arteriole-and-venule-400x-1/ CRICOS Provider Code: 00017B TEQSA: PRV12072 35 CRICOS Provider Code: 00017B TEQSA: PRV12072 © Pearson Education, Inc. 36 Veins Capacitance vessels, blood reservoir Tunica intima Image © Blue Histology forms valves (L = valve leaflet) https://histology.siu.edu/crr/cvguide.htm Tunica media less muscle and elastin than similar diameter artery Tunica adventitia Thickest layer: Collagen and some elastic fibres No visible elastic laminae Often flattened (collapsed) in C/S Larger lumen than arteries CRICOS Provider Code: 00017B TEQSA: PRV12072 37 CRICOS Provider Code: 00017B TEQSA: PRV12072 © Pearson Education, Inc. 38  Large vein (superior and inferior vena cava) Tunica adventitia: thickest layer with bundles of smooth muscle arranged longitudinally Tunica media: Collagen, some smooth muscle cells © 1999-2024, Rice University. Except where CRICOS Provider otherwise Code: 00017B noted, TEQSA: textbooks on this site are licensed PRV12072 39 under a Creative Commons Attribution 4.0 International License. CRICOS Provider Code: 00017B TEQSA: PRV12072 40 https://digitalhistology.org/organs-systems/cardiovascular/vessels/veins/veins-8a/ CRICOS Provider Code: 00017B TEQSA: PRV12072 © Pearson Education, Inc. 41 Peripheral arteries, veins and nerves Tend to travel and branch in parallel https://usmlepathslides.tumblr.com/image/23551886554 CRICOS Provider Code: 00017B TEQSA: PRV12072 42 Heart Three-layered wall Endocardium = tunica intima Myocardium = tunica media Epicardium = tunica adventitia Source: Sobotta Atlas of Anatomy, Volume 2 CRICOS Provider Code: 00017B TEQSA: PRV12072 Paulsen, Friedrich 43 Published January 1, 2023. Pages 1-112. © 2023. Lymphatic vessels Plasma leakage balanced by re- absorption via lymphatic vessels ‘Leakiness’ of capillaries determined by endothelial lining Lymphatic vessels return tissue fluid and leaked proteins to circulation Imbalance = oedema (inflammation, obstruction) CRICOS Provider Code: 00017B TEQSA: PRV12072 44 © Pearson Education, Inc. Lymphatic vessels Lymphatic vessels look like venules, but often have a pink precipitate, no RBCs and lots of WBC, plus you may see valves Very flattened endothelial cells; rudimentary or no basement membrane Histology (Lymphatic System) Lecture 10 - Scientific Figure on ResearchGate. Available from: CRICOS Provider Code: 00017B TEQSA: PRV12072 45 https://www.researchgate.net/figure/Figure-2-Lymphatic-vessels-with-valve_fig2_352056687 [accessed 17 Jan, 2024] CRICOS Provider Code: 00017B TEQSA: PRV12072 46 © Pearson Education, Inc. Histology Guide © Campbell Biology, 12th edition https://histologyguide.com/slidebox/09- CRICOS Provider Code: 00017B TEQSA: PRV12072 48 Published by Pearson © 2021 cardiovascular-system.html Terminology checklist  Endothelium (simple squamous epithelium); subendothelium  External elastic lamina/lamella; internal elastic lamina/lamella  Pericyte  Tunica adventitia; tunica media; tunica intima  Valve  Vasa vasorum (= blood vessel of blood vessel)  Conducting/elastic artery; distributing/muscular artery; arteriole  Capillary (continuous; fenestrated; sinusoidal)  Post-capillary venule; venule; vein (medium, large)  Sphincter  Lymphatic vessel CRICOS Provider Code: 00017B TEQSA: PRV12072 49  bond.edu.au Assistant Professor Joan Roehl Faculty of Health Sciences and Medicine Bond University, Gold Coast, Australia 12/09/2024 CRICOS Provider Code: 00017B TEQSA: PRV12072 50