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Larry M. Frolich, Ph.D.,Human Anatomy
CARDIO-VASCULAR SYSTEM
• Principles• Structures• Two circuits
– Pulmonary– Systemic
• Fetal Circulation• Heart Details• Other details
Larry M. Frolich, Ph.D.,Human Anatomy
What Does C-V System do?
• Circulate blood throughout entire body for– Transport of oxygen to cells– Transport of CO2 away from cells– Transport of nutrients (glucose) to cells– Movement of immune system components
(cells, antibodies)– Transport of endocrine gland secretions
Larry M. Frolich, Ph.D.,Human Anatomy
How does it do it?
• Heart is pump• Arteries and veins are main tubes (plumbing)
– Arteries Away from Heart– Veins to Heart
• Diffusion happens in capillaries (oxygen, CO2, glucose diffuse in or out of blood)
Larry M. Frolich, Ph.D.,Human Anatomy
• Heart/Great Vessels--1 Route
• Smaller aa. vv.--many routes (collateral circulation)
• Capillaries—network where diffusion occurs
Overall Organization of System
Larry M. Frolich, Ph.D.,Human Anatomy
Collateral Circulation
Larry M. Frolich, Ph.D.,Human Anatomy
Walls of Arteries and Veins
• Tunica externa– Outermost layer– CT w/elastin and collagen– Strengthens, Anchors
• Tunica media– Middle layer– Circular Smooth Muscle– Vaso-constriction/dilation
• Tunica intima– Innermost layer– Endothelium– Minimize friction
• Lumen pg 546
Larry M. Frolich, Ph.D.,Human Anatomy
Artery/Vein differencesArteries (aa.) Veins (vv.)
Direction of flow
Blood Away from Heart
Blood to Heart
Pressure Higher Lower
Walls THICKER: Tunica media thicker than tunica externa
THINNER: Tunica externa thicker than tunica media
Lumen Smaller Larger
Valves No valves Valves (see next)
Larry M. Frolich, Ph.D.,Human Anatomy
Larry M. Frolich, Ph.D.,Human Anatomy
Capillaries• Microscopic--one
cell layer thick• Network • Bathed in
extracellular matrix of areolar tissue
• Entire goal of C-V system is to get blood into capillaries where diffusion takes place
Larry M. Frolich, Ph.D.,Human Anatomy
Two circulatory paths
Pulmonary
Systemic
Larry M. Frolich, Ph.D.,Human Anatomy
GREAT VESSELS•Aorta•IVC, SVC•Pulmonary Trunk•Pulmonary Veins
Larry M. Frolich, Ph.D.,Human Anatomy
Heart Chambers and Valves
Larry M. Frolich, Ph.D.,Human Anatomy
Right Heart Chambers: Pulmonary Circuit
• Right Atrium (forms most of posterior of heart)– Receives O2-poor blood from body via IVC, SVC, Coronary sinus
– Ventral wall = rough Pectinate muscle– Fossa Ovalis- on interatrial septum, remnant of Foramen Ovale
• Right Ventricle– Receives O2-poor blood from right atrium through tricuspid valve
– Pumps blood to lungs via Pulmonary Semilunar Valve in pulmonary trunk
– Trabeculae Carnae along ventral surface
– Papillary Muscle-cone-shaped muscle to which chordae tendinae are anchored
– Moderator Band-muscular band connecting anterior papillary muscle to interventricular septum
Larry M. Frolich, Ph.D.,Human Anatomy
Left Heart Chambers: Systemic Circuit
• Left Atrium– Receives O2-rich blood from 4 Pulmonary Veins
– Pectinate Muscles line only auricle
• Left Ventricle (forms apex of heart)– Receives blood from Left Atrium via bicuspid valve
– Pumps blood into aorta via Aortic Semilunar Valve to body
– Same structures as Rt Ventricle: Trabeculae carnae, Papillary muscles, Chordae tendinae
– No Moderator Band
Larry M. Frolich, Ph.D.,Human Anatomy
Heart Valves: Lub*-Dub**• *Tricuspid Valve: Right AV valve
– 3 Cusps (flaps) made of endocardium and CT– Cusps anchored in Rt. Ventricle by Chordae Tendinae– Chordae Tendinae prevent inversion of cusps into atrium– Flow of blood pushes cusps open– When ventricle in diastole (relaxed), cusps hang limp in ventricle– Ventricular contraction increases pressure and forces cusps closed
• *Bicuspid (Mitral) Valve: Left AV valve– 2 cusps anchored in Lft. Ventricle by chordae tendinae– Functions same as Rt. AV valve
• **Semilunar valves: prevents backflow in large arteries– Pulmonary Semilunar Valve: Rt Ventricle and Pulmonary Trunk– Aortic Semilunar Valve: Left Ventricle and Aorta– 3 cusps: blood rushes past they’re flattened, as it settles they’re pushed
down (valve closed)
Larry M. Frolich, Ph.D.,Human Anatomy
Another View
Larry M. Frolich, Ph.D.,Human Anatomy
Location of Heart in Thorax
pg 523
Larry M. Frolich, Ph.D.,Human Anatomy
Location of Heart in Chest
• Oblique Position• Apex = Left of Midline (5th ICS), Anterior to rest of heart• Base (posterior surface) sits on vertebral column
• Superior Right = 3rd Costal Cartilage, 1” right midsternum
• Superior Left = 2nd Costal Cartilage, 1” left midsternum
• Inferior Right = 6th Costal Cartilage, 1” right midsternum• Inferior Left = 5th Intercostal Space at Midclavicular line
Larry M. Frolich, Ph.D.,Human Anatomy
Heart Wall
• Epicardium (most superficial)– Visceral pleura
• Myocardium (middle layer)– Cardiac muscle– Contracts
• Endocardium (inner)– Endothelium on CT– Lines the heart – Creates the valves
pg 524
How does heart muscle get blood supply?
Larry M. Frolich, Ph.D.,Human Anatomy
Blood supply to heart wall
• Rt and Lft Coronary Arteries– Branch from Ascending Aorta– Have multiple branches along heart– Sit in Coronary Sulcus– Coronary Heart Disease
• Cardiac Veins– Coronary Sinus (largest)– Many branches feed into sinus– Sit in Coronary Sulcus
Larry M. Frolich, Ph.D.,Human Anatomy
Heart Innervation• Heart receives visceral
motor innervation– Sympathetic (speeds up)– Parasympathetic (slows
down) p. 534
Larry M. Frolich, Ph.D.,Human Anatomy
Fetal Circulation•No circulation to lungs
•Foramen ovale•Ductus arteriosum
•Circulation must go to placenta•Umbilical aa., vv.
Larry M. Frolich, Ph.D.,Human Anatomy
Adult remnants of fetal circulation
Adult Fetus
Fossa ovale Foramen ovale
Ligamentum arteriosum Ductus arteriosus
Medial umbilical ligaments Umbilical aa.(within fetus)
Round ligament (ligamentum teres) of liver
Umbilical v.(within fetus)
Ligamentum venosum Ductus venosus
Medial umbilical ligament Umbilical cord (leaving fetus)
Larry M. Frolich, Ph.D.,Human Anatomy
Hepatic Portal System
Larry M. Frolich, Ph.D.,Human Anatomy
Lymphatic System…The Players:
• Lymph- clear fluid from loose areolar CT around capillaries
• Lymphatic capillaries (near blood capillaries) • Lymph collecting vessels (small, 3 tunicas, valves)• Lymph nodes (sit along collecting vessels)-clean
lymph of pathogens, they are NOT glands• Lymphatic trunks (convergence large collecting
vessels)– Lumbar, intestinal, bronchomediastinal, subclavian, jugular
• Lymphatic ducts empty into veins of neck
Larry M. Frolich, Ph.D.,Human Anatomy
Lymphatic System--Function
• Function: to collect excess tissue fluid collecting at arteriole end and return leaked blood proteins to blood (maintain osmotic pressure needed to take up water into bloodstream)
• Lymph moved through vessels– Pulse of nearby arteries– Contraction of surrounding skeletal muscle– Regular movement of body (wiggling legs)– Muscle in Tunica Media
• Lacteals-lymphatic capillaries w/unique function– In mucosa of small intestine, receive digested fat from
intestine– Fatty lymph becomes milky = Chyle– Chyle goes to bloodstream