DOCSLIB.ORG

Cardiovascular System: Vessels Miles of Vessels Per Human Body

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

Over 60,000 Cardiovascular System: Vessels miles of vessels per human body Cardiovascular System – Vessels Blood Vessel Anatomy: (branch / diverge / fork) Elastic Muscular Arterioles Arteries Arteries Vessel Types: Heart (nutrient 1) Arteries (away from heart) exchange) 2) Capillaries Capillaries 3) Veins (toward heart) Veins Venules (join / merge / converge) Cardiovascular System – Vessels Blood Vessel Anatomy: O2-rich; CO2-poor Pulmonary circuit (short, low pressure loop) O2-poor; CO2-rich (long, high pressure loop) Systemic circuit O2-poor; O2-rich; CO2-rich CO2-poor % / volume not fixed: Function: • Alteration of arteriole size 1) Circulate nutrients / waste • Alteration of cardiac output 2) Regulate blood pressure • Combination of two above Costanzo (Physiology, 4th ed.) – Figure 4.1 1 Cardiovascular System – Vessels Blood Vessel Anatomy: Only tunic present in capillaries Vessels composed of distinct tunics : 1) Tunica intima Tunica intima • Endothelium (simple squamous epithelium) • Connective tissue ( elastic fibers) 2) Tunica media • Smooth muscle / elastic fibers • Regulates pressure / circulation • Sympathetic innervation Lumen Vasa 3) Tunica externa vasorum • Loose collagen fibers • Nerves / lymph & blood vessels • Protects / anchors vessel Vasomotor stimulation = vasoconstriction Tunica media Vasomotor relaxation = vasodilation Tunica externa Cardiovascular System – Vessels Relative tissue makeup Blood Vessel Anatomy: Arteriosclerosis: Arteries: Hardening / stiffening of arteries Endothelium Elastic tissue Elastic Fibrous tissue Fibrous Major groups: muscleSmooth D = Diameter T = Thickness 1) Elastic Arteries (conducting arteries): D: 1.5 cm • Large, thick-walled (near heart) T: 1.0 mm • [elastic fibers] (pressure reservior) 2) Muscular Arteries (distributing arteries): • Deliver blood to organs D: 6.0 mm T: 1.0 mm • [smooth muscle] (vasoconstriction) 3) Arterioles: • Control blood into capillaries D: 37.0 m T: 6.0 m • Neural / hormonal / local controls Marieb & Hoehn (Human Anatomy and Physiology, 8th ed.) – Table 19.1 Cardiovascular System – Vessels Relative tissue makeup Blood Vessel Anatomy: Capillaries: Endothelium Elastic tissue Elastic Fibrous tissue Fibrous Smooth muscle Smooth 1) Capillaries: • Location of blood / tissue interface D: 9.0 m T: 1.0 m • Stabilized by pericytes (smooth muscle cells) Types of Capillaries: A) Continuous 2) Fenestrated 3) Sinusoidal: • Uninterrupted lining • Oval pores present • Holes / clefts present • Found throughout body • Located in high absorption / • Allow passage of large (most common type) filtration regions (e.g., kidney) molecules (e.g., liver) Marieb & Hoehn (Human Anatomy and Physiology, 8th ed.) – Table 19.1 / Figure 19.3 2 Cardiovascular System – Vessels Blood Vessel Anatomy: Capillaries: Capillaries do not function independently – Instead they form interweaving networks called capillary beds Vascular True capillaries Not all capillaries are perfused shunt with blood at all times… Terminal Postcapillary Precapillary sphincters arteriole venule • 10 - 100 capillaries / bed • Sphincters control blood flow a) Vascular shunt through capillary bed b) True capillaries Marieb & Hoehn (Human Anatomy and Physiology, 8th ed.) – Figure 19.4 Cardiovascular System – Vessels Relative tissue makeup Blood Vessel Anatomy: Leukocyte Veins: margination Endothelium Elastic tissue Elastic Fibrous tissue Fibrous Major groups: muscleSmooth 1) Venules: D: 20.0 m • Formed where capillaries unite T: 1.0 m • Extremely porous 2) Veins (capacitance vessels): D: 5.0 mm • Large lumen; “volume” sink T: 0.5 mm • Low pressure environment Venous sinuses: Specialized, flattened veins composed only of endothelium; supported by surrounding tissues Marieb & Hoehn (Human Anatomy and Physiology, 8th ed.) – Figures 19.3 / 19.5 3 Cardiovascular System – Vessels Vascular anastomoses: Blood Vessel Anatomy: Regions where vessels unite, forming interconnections Heart Heart Venous anastomoses are common; vein blockages collateral rarely lead to tissue death Arteriovenous channels anastomosis Arterial anastomoses provide alternative channels for blood to reach locations • Joints • Abdominal organs • Brain Retina, spleen, & kidney have Great saphenous limited collateral circulation vein harvest Marieb & Hoehn (Human Anatomy and Physiology, 8th ed.) – Figure 19.2 Cardiovascular System – Vessels Would you want Pathophysiology: Most common form to find this pipe of arteriosclerosis in your house? Atherosclerosis: Formation of atheromas (small, patchy thickenings) on wall of vessel; intrude into lumen 1) Endothelium injured 3) Fibrous plaque forms • Infection / hypertension • Collagen / elastin fibers deposited around dying or 2) Lipids accumulate / oxidize dead foam cells • LDLs collect on tunica intima 4) Plaque becomes unstable Foam cells: • Calcium collects in plaque Macrophages engorged • Vessel constricts; arterial wall with LDLs; form fatty streak frays / ulcerates (= thrombus) Link Outcome: Statins: • Myocardial infarctions Cholesterol-lowering drugs • Strokes • Aneurysms Angioplasty / Stent Bypass surgery Cardiovascular System – Vessels To stay alive, blood must Hemodynamics: be kept moving… Blood Flow: Volume of blood flowing past a point per given time (ml / min) The velocity of blood flow is not related to proximity of heart, but depends on the diameter and cross-sectional area of blood vessels v = Q / A v = Velocity (cm / sec) Q = Flow (mL / sec) A = Cross-sectional area (cm2) A = r2 Costanzo (Physiology, 4th ed.) – Figure 4.4 4 Cardiovascular System – Vessels To stay alive, blood must Hemodynamics: be kept moving… Blood Flow: Volume of blood flowing past a point per given time (ml / min) The velocity of blood flow is not related to proximity of heart, but depends on the diameter and cross-sectional area of blood vessels v = Q / A Blood velocity is highest in the aorta and lowest in the capillaries Capillaries Artery Vein Randall et al. (Eckert Animal Physiology, 5th ed.) – Figure 12.23 Cardiovascular System – Vessels v = Q / A A man has a cardiac output of 5.5 L / min. The diameter of his aorta is estimated to be 20 mm, and the total cross-sectional area of his systemic capillaries is estimated to be 2500 cm2. What is the velocity of blood flow in the aorta relative to the velocity of blood flow in the capillaries? cm3 (1 cm) A = r2 A = (3.14) (10 mm)2 A = 3.14 cm2 (5500 mL) 5.5 L / min 5500 cm3 / min vcapillaries = vaorta = 2500 cm2 3.14 cm2 800x difference vcapillaries = 2.2 cm / min vaorta = 1752 cm / min Cardiovascular System – Vessels To stay alive, blood must Hemodynamics: be kept moving… Blood flow through a blood vessel or a series of blood vessels is determined by blood pressure and peripheral resistance Blood Pressure: Force per unit area on wall of vessel (mm Hg) • The magnitude of blood flow is directly proportional to the size of the pressure difference between two ends of a vessel Blood Flow (Q) = Difference in blood pressure ( P) • The direction of blood flow is determined by the direction of the pressure gradient Always moves from high to low pressure 5 Cardiovascular System – Vessels To stay alive, blood must Hemodynamics: be kept moving… Heart generates initial pressure Vessel resistance generates pressure gradient Costanzo (Physiology, 4th ed.) – Figure 4.8 Cardiovascular System – Vessels To stay alive, blood must Hemodynamics: be kept moving… Blood flow through a blood vessel or a series of blood vessels is determined by blood pressure and peripheral resistance Peripheral Resistance: Amount of friction blood encounters passing through vessels (mm Hg / mL / min) • Blood flow is inversely proportional to resistance encountered in the system 1 Blood Flow (Q) = Peripheral resistance (R) The major mechanism for changing blood flow in the cardiovascular system is by changing the resistance of blood vessels, particularly the arterioles Cardiovascular System – Vessels To stay alive, blood must Hemodynamics: be kept moving… (difference in voltage) (current) Difference in blood pressure ( P) Blood Flow (Q) = Peripheral resistance (R) (electrical resistance) Analogous to Ohm’s Law (V = I x R OR I = V / R) Q = P / R A man has a renal blood flow of 500 mL / min. The renal atrial pressure R = P / Q is 100 mm Hg and the renal venous pressure is 10 mm Hg. 100 mm Hg – 10 mm Hg R = What is the vascular resistance of 500 mL / min the kidney for this man? R = 0.18 mm Hg / mL / min 6 Cardiovascular System – Vessels To stay alive, blood must Hemodynamics: be kept moving… The factors that determine the resistance of a blood vessel to blood flow are expressed by Poiseuille’s (pwä-zwēz) Law: Powerful relationship! R = Resistance 8Lη Slight diameter change R = η = Viscosity of blood equals r4 L = Length large resistance change r = Radius 1) Blood viscosity 2) Vessel Length 3) Vessel Diameter viscosity = resistance length = resistance diameter = resistance Cardiovascular System – Vessels To stay alive, blood must Hemodynamics: be kept moving… The total resistance associated with a set of blood vessels also depends on whether the vessels are arranged in series or in parallel A) Series resistance: Sequential arrangement (e.g., pathway within single organ) Arteriolar resistance is the greatest which equates to the area with the greatest decrease in pressure The total resistance is equal to the sum of the individual resistances Costanzo (Physiology, 4th ed.) – Figure 4.5 Cardiovascular System – Vessels To stay alive, blood must Hemodynamics: be kept moving… The total resistance associated with a set
Recommended publications
  • Chapter 20 *Lecture Powerpoint the Circulatory System: Blood Vessels and Circulation

    Chapter 20 *Lecture Powerpoint the Circulatory System: Blood Vessels and Circulation

    Chapter 20 *Lecture PowerPoint The Circulatory System: Blood Vessels and Circulation *See separate FlexArt PowerPoint slides for all figures and tables preinserted into PowerPoint without notes. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Introduction • The route taken by the blood after it leaves the heart was a point of much confusion for many centuries – Chinese emperor Huang Ti (2697–2597 BC) believed that blood flowed in a complete circuit around the body and back to the heart – Roman physician Galen (129–c. 199) thought blood flowed back and forth like air; the liver created blood out of nutrients and organs consumed it – English physician William Harvey (1578–1657) did experimentation on circulation in snakes; birth of experimental physiology – After microscope was invented, blood and capillaries were discovered by van Leeuwenhoek and Malpighi 20-2 General Anatomy of the Blood Vessels • Expected Learning Outcomes – Describe the structure of a blood vessel. – Describe the different types of arteries, capillaries, and veins. – Trace the general route usually taken by the blood from the heart and back again. – Describe some variations on this route. 20-3 General Anatomy of the Blood Vessels Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Capillaries Artery: Tunica interna Tunica media Tunica externa Nerve Vein Figure 20.1a (a) 1 mm © The McGraw-Hill Companies, Inc./Dennis Strete, photographer • Arteries carry blood away from heart • Veins
  • The Circulatory System

    The Circulatory System

    TheThe CirculatoryCirculatory SystemSystem Xue Hui DepartmentDepartment ofof HistologyHistology && EmbryologyEmbryology TheThe CirculatoryCirculatory SystemSystem Cardiovascular system (blood vascular system) Heart Artery Capillary Vein Lymphatic vascular system Lymphatic capillary Lymphatic vessel Lymphatic duct II GeneralGeneral structurestructure ofof thethe bloodblood vesselsvessels Tunica intima Tunica media Tunica adventitia Drawing of a medium-sized muscular artery, showing its layers. II GeneralGeneral structurestructure ofof thethe bloodblood vesselsvessels IIII ArteryArtery Large artery Medium-sized artery Small artery Arteriole II Artery LargeLarge arteryartery Structure Tunica intima Tunica media 40-70 layers of elastic lamina Smooth muscle cells, collagenous fibers Tunica adventitia Function Carry the blood from the heart to the middle arteries Tunica Tunica intima intima Tunica Tunica media media Tunica Tunica adventitia adventitia Transverse sections showing part of a large elastic artery showing a well developed tunica media containing several elastic laminas. II Artery MediumMedium--sizedsized arteryartery Structure Tunica intima: clear internal elastic membrane Tunica media: 10-40 layers of smooth muscle cells Tunica adventitia: external elastic membrane Function Regulate the distribution of the blood to various parts of the body Tunica Internal intima elastic membrane Tunica media External elastic membrane Tunica adventitia II Artery SmallSmall arteryartery Structure characteristic Diameter:0.3-1mm Tunica intima: clear
  • Infliximab, a TNF-Α Inhibitor, Reduces 24-H Ambulatory

    Infliximab, a TNF-Α Inhibitor, Reduces 24-H Ambulatory

    Journal of Human Hypertension (2014) 28, 165–169 & 2014 Macmillan Publishers Limited All rights reserved 0950-9240/14 www.nature.com/jhh ORIGINAL ARTICLE Infliximab, a TNF-a inhibitor, reduces 24-h ambulatory blood pressure in rheumatoid arthritis patients S Yoshida1, T Takeuchi1, T Kotani1, N Yamamoto1, K Hata1, K Nagai1, T Shoda1,STakai2, S Makino1 and T Hanafusa1 Tumour necrosis factor-alpha (TNF-a) is an important mediator in the pathogenesis of rheumatoid arthritis (RA) and hypertension. TNF-a inhibitors improve clinical symptoms and inhibit joint destruction in RA, but their effect on blood pressure (BP) has not been fully investigated. We measured 24-h BP using an ambulatory BP monitor in 16 RA patients treated with a TNF-a inhibitor, infliximab, to investigate its influence on BP and its association with the regulatory factors of BP and renin-angiotensin-aldosterone and sympathetic nervous systems. Infliximab significantly reduced the 24-h systolic BP (SBP) from 127.4±21.8 to 120.1±23.4 mm Hg (Po0.0001). Particularly, morning BP (0600–0800 h) decreased from 129.7±19.7 to 116.9±13.4 mm Hg (Po0.0001), and daytime BP decreased from 131.8±15.1 to 122.5±13.7 mm Hg (Po0.0001). Infliximab significantly reduced the plasma level of norepinephrine and plasma renin activity (PRA) (from 347.5±180.7 to 283.0±181.8 pg ml À 1 and 2.6±2.7 to 2.1±2.9 ng ml À 1 h À 1, respectively) but did not significantly reduce the plasma levels of dopamine and epinephrine.
  • Threatening External Iliac Vein Injury During Total Hip Arthroplasty

    Threatening External Iliac Vein Injury During Total Hip Arthroplasty

    경희의학 : 제 27 권 제 1 호 □ 증 례 □ J Kyung Hee Univ Med Cent : Vol. 27, No. 1, 2011 Threatening External Iliac Vein Injury during Total Hip Arthroplasty Kang Woo Lee, M.D., Jo Young Hyun, M.D., Jae Woo Yi, M.D., Ph.D. Department of Anesthesiology and Pain Medicine, School of Medicine, Kyung Hee University, Seoul, Korea INTRODUCTION nal iliac vein during total hip replacement, which resulted in hemorrhagic shock. Since its inception in the 1960’s, total hip arthro- plasty (THA) has grown in volume and complexity. CASE REPORT Total hip arthroplasty has revolutionized the treatment of end-stage hip arthritis and is felt to be among the A 63-year-old female patient (150 cm, 59 kg) was most cost effective of all medical interventions diagnosed as secondary osteoarthritis of left hip joint. available.(1) The complications associated with THA She was scheduled to undergo total hip replacement. have been increased as a result of increasing life The patient’s previous medical history entailed ten expectancy and widened indications for THA. But the years of hypertension, which was well-controlled with complications related to total hip arthroplasty are not oral anti-hypertensive drugs. Routine monitors such as common. Especially vascular injuries are very rare but electrocardiogram, pulse oxymeter, non-invasive blood can cause limb loss or become life threatening. A pressure were used. Induction of anesthesia was achieved thorough understanding of the possible complications with propofol 120 mg, rocuronium 50 mg intravenously. following total hip arthroplasty aids in optimizing Anesthesia was maintained with sevoflurane. After loss patient outcomes The occurrence of the complication of all four twitches from the train-of-four obtained by related to THA has not been emphasized enough in ulnar nerve stimulation, endotracheal intubation was anesthesia literature and has been overlooked in the performed.
  • Radionuclear Measurement of Peripheral Hemodynamics In

    Radionuclear Measurement of Peripheral Hemodynamics In

    RadionuclearMeasurementof Peripheral Hemodynamics in Selection of Vasodilators for Treatment of Heart Failure Yasuhiro Todo, Mitsumasa Ohyanagi, Ryu Fujisue, and Tadaaki Iwasaki Hyogo College ofMedicine, Nishinomiya, Japan Inorder to select the optimal vasodilator for the treatment of patients with congestive heart failure (CHF), the acute effects of three vasodilators (isosorbide dinitrate (ISDN) 5 mg, nifedipine 10 mg, and prazosin 1 mg) on peripheral capacitance and resistance vessels (CV and RV)were evaluated by a newly devised radionuclear technique (Study 1).Thirty-six @ patients with chronic CHF were dividedinto Group A (ejectionfraction (EF) 35%, n = 20, mean EF: 47.2 ±6.5%) and B (EF < 35%, n = 16, mean EF: 24.8 ±7.1%). ISDNproduced the strongest CVdilatation(25% in both groups). Nifedipinereduced RVtone in Groups A and B (14% and 27%, respectively),and CVtone in Group A (6%). Prazosin had the most prominent effects on both vessels in Group B. From these results, it appeared: (a) ISDN is indicated for the cases with increased CV tone, (b) nifedipine is suitable for those with @ increased RV tone, (C)in cases of increased tone in both vessels, nifedipine (when EF 35%) or prazosin (when EF < 35%) is optimal.To evaluate the validityof this assignment, 49 subjects with CHF were divided into Group 1 (n = 16, increased CV tone), Group 2 (n = 17, increased RV tone), and Group 3 (n = 16, increased CV and RV tone) in Study 2. In Group 1, the changes of all indexes were not significantly different between the subjects treated with optimal drug based on the assignment (subgroup P) and those with a non-optimaldrug (subgroup N)after 2 wk of therapy.
  • NROSCI/BIOSC 1070 and MSNBIO 2070 September 27, 2017

    NROSCI/BIOSC 1070 and MSNBIO 2070 September 27, 2017

    NROSCI/BIOSC 1070 and MSNBIO 2070 September 27, 2017 Cardiovascular 6 Special Circulations Coronary Muscle The coronary arteries branch directly from the aorta, and provide the perfusion of the heart. Although blood actually is pumped through the heart, only ~ 100 µm of the inner endocardial surface can obtain significant amounts of nutrition directly from the blood supply in the cardiac chambers. Blood flow through the coronary capillaries during systole and diastole is different than in most other tissues of the body. The blood flow to the ventricles falls during systole, and increases during diastole. During ventricular contrac- tion, blood flow through the capillaries is obstructed by compression of the vessels. Thus, blood flow increases during diastole when the muscle around the vessels relaxes. Autoregulatory mechanisms are paramount in adjusting the blood flow through the heart. Another major influence on dilation of the coronary arteries is epinephrine released from the adrenal gland. Cerebral Circulation The cerebral circulation is almost completely insensitive to neural and hormonal influences that produce vasoconstriction elsewhere in the body. By far the predominant factor that controls blood flow through the cerebral circulation is paracrine release. In particular, carbon dioxide has a strong vasodilation effect on the cerebral vessels. Skeletal Muscle Circulation Control of blood flow to skeletal muscle is in many respects similar to that in the heart. Paracrine fac- tors have strong influences, and vasodilation is induced by the release of epinephrine from the adrenal gland. A major difference between the two circulations is that skeletal muscle arterioles are richly in- nervated by sympathetic vasoconstrictor fibers, and are major resistance vessels to contribute to total peripheral resistance.
  • Anatomy Review: Blood Vessel Structure & Function

    Anatomy Review: Blood Vessel Structure & Function

    Anatomy Review: Blood Vessel Structure & Function Graphics are used with permission of: Pearson Education Inc., publishing as Benjamin Cummings (http://www.aw-bc.com) Page 1. Introduction • The blood vessels of the body form a closed delivery system that begins and ends at the heart. Page 2. Goals • To describe the general structure of blood vessel walls. • To compare and contrast the types of blood vessels. • To relate the blood pressure in the various parts of the vascular system to differences in blood vessel structure. Page 3. General Structure of Blood Vessel Walls • All blood vessels, except the very smallest, have three distinct layers or tunics. The tunics surround the central blood-containing space - the lumen. 1. Tunica Intima (Tunica Interna) - The innermost tunic. It is in intimate contact with the blood in the lumen. It includes the endothelium that lines the lumen of all vessels, forming a smooth, friction reducing lining. 2. Tunica Media - The middle layer. Consists mostly of circularly-arranged smooth muscle cells and sheets of elastin. The muscle cells contract and relax, whereas the elastin allows vessels to stretch and recoil. 3. Tunica Adventitia (Tunica Externa) - The outermost layer. Composed of loosely woven collagen fibers that protect the blood vessel and anchor it to surrounding structures. Page 4. Comparison of Arteries, Capillaries, and Veins • Let's compare and contrast the three types of blood vessels: arteries, capillaries, and veins. • Label the artery, capillary and vein. Also label the layers of each. • Arteries are vessels that transport blood away from the heart. Because they are exposed to the highest pressures of any vessels, they have the thickest tunica media.
  • Blood Vessels: Part A

    Blood Vessels: Part A

    Chapter 19 The Cardiovascular System: Blood Vessels: Part A Blood Vessels • Delivery system of dynamic structures that begins and ends at heart – Arteries: carry blood away from heart; oxygenated except for pulmonary circulation and umbilical vessels of fetus – Capillaries: contact tissue cells; directly serve cellular needs – Veins: carry blood toward heart Structure of Blood Vessel Walls • Lumen – Central blood-containing space • Three wall layers in arteries and veins – Tunica intima, tunica media, and tunica externa • Capillaries – Endothelium with sparse basal lamina Tunics • Tunica intima – Endothelium lines lumen of all vessels • Continuous with endocardium • Slick surface reduces friction – Subendothelial layer in vessels larger than 1 mm; connective tissue basement membrane Tunics • Tunica media – Smooth muscle and sheets of elastin – Sympathetic vasomotor nerve fibers control vasoconstriction and vasodilation of vessels • Influence blood flow and blood pressure Tunics • Tunica externa (tunica adventitia) – Collagen fibers protect and reinforce; anchor to surrounding structures – Contains nerve fibers, lymphatic vessels – Vasa vasorum of larger vessels nourishes external layer Blood Vessels • Vessels vary in length, diameter, wall thickness, tissue makeup • See figure 19.2 for interaction with lymphatic vessels Arterial System: Elastic Arteries • Large thick-walled arteries with elastin in all three tunics • Aorta and its major branches • Large lumen offers low resistance • Inactive in vasoconstriction • Act as pressure reservoirs—expand
  • 24. the Endothelial Glycocalyx (C Alphonsus)

    24. the Endothelial Glycocalyx (C Alphonsus)

    Part I Anaesthesia Refresher Course – 2018 24 University of Cape Town The Endothelial Glycocalyx Dr Christella Alphonsus Dept of Anaesthesia & Perioperative Medicine University of Cape Town Overview The glycocalyx is a complex gel layer that coats all healthy vascular endothelium. This layer exists in dynamic interaction between flowing blood and the endothelial cell wall. It plays a pivotal role in vascular protection, modulation and haemostasis. Components The endothelial glycocalyx is essentially made up of glycoproteins or proteoglycans but there is great diversity in structure and function within these two groups. Proteoglycans have a protein core to which are attached negatively charged glycosaminoglycan (GAG) side chains. There are different types of proteoglycans and they vary according to: the core protein size, the number of GAG side chains and whether they are bound or not bound to the cell membrane. Syndecans and glypicans are first bound to the cell membrane and the GAG side chains are attached later. Other proteoglycans (perlecans, versicans, decorins, biglycans, mimecans) are first bound to GAGs and then secreted by the endothelial cells. There are five types of GAG side chains: heparan sulphate makes up 50–90%, with the remainder composed of hyaluronic acid and chondroiton, dermatan and keratin sulphates. Hyaluronic acid is the only GAG not usually bound to a core protein and forms viscous solutions with water. Glycoproteins act as adhesion molecules and contribute to the coagulation, fibrinolytic and haemostatic systems. These include E and P selectin which are expressed after stimulation by histamine, thrombin, interleukin-1 and tumour necrosis factora (TNF-α). Ligands for leucocyte and platelet adhesion ICAM-1, ICAM-2, VCAM-1, PECAM-1 are also expressed within the glycocalyx.
  • Vessels and Circulation

    Vessels and Circulation

    CARDIOVASCULAR SYSTEM OUTLINE 23.1 Anatomy of Blood Vessels 684 23.1a Blood Vessel Tunics 684 23.1b Arteries 685 23.1c Capillaries 688 23 23.1d Veins 689 23.2 Blood Pressure 691 23.3 Systemic Circulation 692 Vessels and 23.3a General Arterial Flow Out of the Heart 693 23.3b General Venous Return to the Heart 693 23.3c Blood Flow Through the Head and Neck 693 23.3d Blood Flow Through the Thoracic and Abdominal Walls 697 23.3e Blood Flow Through the Thoracic Organs 700 Circulation 23.3f Blood Flow Through the Gastrointestinal Tract 701 23.3g Blood Flow Through the Posterior Abdominal Organs, Pelvis, and Perineum 705 23.3h Blood Flow Through the Upper Limb 705 23.3i Blood Flow Through the Lower Limb 709 23.4 Pulmonary Circulation 712 23.5 Review of Heart, Systemic, and Pulmonary Circulation 714 23.6 Aging and the Cardiovascular System 715 23.7 Blood Vessel Development 716 23.7a Artery Development 716 23.7b Vein Development 717 23.7c Comparison of Fetal and Postnatal Circulation 718 MODULE 9: CARDIOVASCULAR SYSTEM mck78097_ch23_683-723.indd 683 2/14/11 4:31 PM 684 Chapter Twenty-Three Vessels and Circulation lood vessels are analogous to highways—they are an efficient larger as they merge and come closer to the heart. The site where B mode of transport for oxygen, carbon dioxide, nutrients, hor- two or more arteries (or two or more veins) converge to supply the mones, and waste products to and from body tissues. The heart is same body region is called an anastomosis (ă-nas ′tō -mō′ sis; pl., the mechanical pump that propels the blood through the vessels.
  • Relationship Between Vasodilatation and Cerebral Blood Flow Increase in Impaired Hemodynamics: a PET Study with the Acetazolamide Test in Cerebrovascular Disease

    Relationship Between Vasodilatation and Cerebral Blood Flow Increase in Impaired Hemodynamics: a PET Study with the Acetazolamide Test in Cerebrovascular Disease

    CLINICAL INVESTIGATIONS Relationship Between Vasodilatation and Cerebral Blood Flow Increase in Impaired Hemodynamics: A PET Study with the Acetazolamide Test in Cerebrovascular Disease Hidehiko Okazawa, MD, PhD1,2; Hiroshi Yamauchi, MD, PhD1; Hiroshi Toyoda, MD, PhD1,2; Kanji Sugimoto, MS1; Yasuhisa Fujibayashi, PhD2; and Yoshiharu Yonekura, MD, PhD2 1PET Unit, Research Institute, Shiga Medical Center, Moriyama, Japan; and 2Biomedical Imaging Research Center, Fukui Medical University, Fukui, Japan Key Words: acetazolamide; cerebrovascular disease; cerebral The changes in cerebral blood flow (CBF) and arterial-to- blood volume; vasodilatory capacity; cerebral perfusion pressure capillary blood volume (V0) induced by acetazolamide (ACZ) are expected to be parallel each other in the normal circula- J Nucl Med 2003; 44:1875–1883 tion; however, it has not been proven that the same changes in those parameters are observed in patients with cerebro- vascular disease. To investigate the relationship between changes in CBF, vasodilatory capacity, and other hemody- namic parameters, the ACZ test was performed after an The ability of autoregulation to maintain the cerebral 15O-gas PET study. Methods: Twenty-two patients with uni- blood flow (CBF), which resides in the cerebral circulation lateral major cerebral arterial occlusive disease underwent despite transient changes in systemic mean arterial blood 15 PET scans using the H2 O bolus method with the ACZ test pressure, has been shown to occur via the mechanism of 15 after the O-gas steady-state method. CBF and V0 for each arteriolar vasodilatation in the cerebral circulation (1). The subject were calculated using the 3-weighted integral vasodilatory change in the cerebral arteries is assumed for method as well as the nonlinear least-squares fitting method.
  • Blood Vessels

    Blood Vessels

    BLOOD VESSELS Blood vessels are how blood travels through the body. Whole blood is a fluid made up of red blood cells (erythrocytes), white blood cells (leukocytes), platelets (thrombocytes), and plasma. It supplies the body with oxygen. SUPERIOR AORTA (AORTIC ARCH) VEINS & VENA CAVA ARTERIES There are two basic types of blood vessels: veins and arteries. Veins carry blood back to the heart and arteries carry blood from the heart out to the rest of the body. Factoid! The smallest blood vessel is five micrometers wide. To put into perspective how small that is, a strand of hair is 17 micrometers wide! 2 BASIC (ARTERY) BLOOD VESSEL TUNICA EXTERNA TUNICA MEDIA (ELASTIC MEMBRANE) STRUCTURE TUNICA MEDIA (SMOOTH MUSCLE) Blood vessels have walls composed of TUNICA INTIMA three layers. (SUBENDOTHELIAL LAYER) The tunica externa is the outermost layer, primarily composed of stretchy collagen fibers. It also contains nerves. The tunica media is the middle layer. It contains smooth muscle and elastic fiber. TUNICA INTIMA (ELASTIC The tunica intima is the innermost layer. MEMBRANE) It contains endothelial cells, which TUNICA INTIMA manage substances passing in and out (ENDOTHELIUM) of the bloodstream. 3 VEINS Blood carries CO2 and waste into venules (super tiny veins). The venules empty into larger veins and these eventually empty into the heart. The walls of veins are not as thick as those of arteries. Some veins have flaps of tissue called valves in order to prevent backflow. Factoid! Valves are found mainly in veins of the limbs where gravity and blood pressure VALVE combine to make venous return more 4 difficult.