6 applo VASCULAR SYSTEM aK r i 5 ardio-vascula system is sometimes called the bl. d x . jood-vaser the circulatory system. The cardiovascular syst “ood-vascular or a essels] The system is fespons system consists of the eal the tissues of the body. Th, through the tse y: The heart acts plod ¢ for this erroulenor Blood which is ben fon 7 aa the py the arteries, is brought back by the Veins. emis fissue® E HEART TH (Greek- Cardia Latin-Cor) jntroduction The heart is a vital organ of the body receiving deoxygented blood on ight side and giving out oxygenated blood from the left side. It is ible for the circulation of the 1 a conical and hollow muscular organ. Location It lies in the middle mediastinum obliquely behind the body of the temum and adjoining parts of the costal cartilages, so that 1/3 oft les es tp ihe right and 2/3 to the left. _pimensions - 12 mx 9 cm. s and 250 g in females. ever, to function as a pump, its wall needs to osed of 3 layers, outer layer. It is actually the visceral es the heart function as a pump. It is made up of endothelium ——ee — si Cardio Vascular system it and felt in this region ¢; External features BION called the Base Pex 1. Apex Human heart has an apex whi and to the left. It is tal space 3 1/2 In the nw ich is directed ted posteriorly and forms surface of the heart. Itisformeq the es left atrium and by a small Part of 4 It shows the chenings of rf downwards, forwards interci situated in the | th! inches lateral to the midsternal line. Tht living subject the pulsations may be seen Pulmonary artery Superior vena cava = l Right pulmonary arteries eft PL nary arteries Left atrium Left pul . Right atrium Cee veins Right coronary artery Right pulmonary veins . Cirui accep Conus arteriosus branch ery Left anterior descendin Right anterior ventricular artery Left ventricle i artery Right marginal artery Right ventricle Inferior vena cava Fig. Heart- anterior view Right coronary artery (in coronary sulcus) Posterior interventricular artery (in posterior interventricular sulcus) Middle cardiac vein Right ventricle Fig. Heart-posterior viewie lar groove oF coronary ov nd ventricles are separated “ee the atriovent other by the atrioventricular e gverlapped anteriorly by the and the pulmonary trunk . gel af is ve atrial roove - The two atria are "4 from each other by the interatrial pe is also overlapped anteriorly by ing aorta. and the pulmonary trunk. ater groove -The_two_ 4 of icles 2 separated from each other by es rorventicula groove which may be, tie i anterior down ji Poster! present 7 interventricular groove-It runs ‘ior interventricular groove - It is infer of the heart. Borders The heart has 4 borders, a) Upper porder - It is oblique and formed by the left atrium. — b) Right porder - It is vertical and formed 5 ——— by the right atrium. ¢) Left porder - It is olique and formed by x — the left ventricle. d) Inferior porder - It is horizontal and formed by the right ventricle. Surfaces a) Anterior surface (Sterno costal surface) It is formed mainly by the right atrium an the right ventricle. Most of the sternocostal surface is covered by lungs’ except the area at the cardiac notch of the left lung which js uncovered. This area 1s called the area of superficial cardiac dullness. bp) Inferior surface - (Diaphragmatic surface) Te iad BBD Cardio Vascular system Itis fo rme i 0 te ee aeatceand the righ psi on the central tendon of the a 2) n. t is traversed by the poste! . rventricular groove s —| c) Left surface e- ° ventricle It is formed by the left Chambers T ; ; eer ec - four chambers namely i entricle, left atrium and left ventricle. The two atria are separated from each other by interatrial septum. The two ventricles are separated rom each other by interventricular septum. The upper part of each atrium has an aj endage called the auricle. The heart js obliquely placed So the right atrium and the right ventricle lie anterior to the left atrium and the left ventricle respectively. im Introduction It is the right uppeT chamber receiving deoxygenated blood from the whole body and pumps it to the right ventricle through tricuspid opening. The right atrium forms the right border, sternocostal_ surface and small part of base oF he heart. Shape It is vertically elongated between openi of the superior vena cava above and of the inferior vena cava below. Exterior of the right atrium ing It shows following features, Right auricle - The projected part of the upper end of the right atrium is called the right auricle. It overlaps the root of the nd partly the infundibulum ascending aorta al Ball of the right ventricle. NS” W]eortic arch | f syste Cardio Vase ula ma) ugamentum artriosun | Left pulmonary artery Pulmonary trunk Left pulmonary veins wight Left atrium aight ul Aortic semilunar valve ist right auricle Left atrioventricular valve Interatrial septum Pulmonary semilunar valve ight avium | ac ae ca Trabeculae carneae veel ve interventricular septum, Left ventricle ight atrio Chordae tendinede papillary muscle Right ventricle Inferior vena cave Descending aorta fig. Interior of the heart the crista terminalis running fory, downwards to the atrioventricular atds gives comb like appearance. ac = It is a shallow vertical nt border of the right perior vena cava ava below. The , Posterior part or Sinus_venan cum. | b, Sulcus terminalis groove along the rigl atrium. It passes from the su fice, I, above to the inferior vena ¢ upper part of the sulcus terminalis contains smooth walled. Thi : mooth walled. This part shows foloyi. node which acts as the openings of the tributaries, us following the sinuatrial (S.A.) pacemaker of the heart. a i c Right atrioventricular groove It separates SD superior vous eara the upper end the right atrium from the right ventricle. ii) Inferior vena cava at the lower It lodges the right coronary artery and the Sad small cardiac vein. iii) Coronary sinus betw een th of the inferior vena cava and in te Interior of the right atrium coe — The inti of the right atria chia ED au cordis minimae - These are the small veins present in the wall of all the fo. Abeer Nur into 3 parts, aan oa They open into the right atrium b) Posterior part or Sim , i lus Vel ' ‘narum, ¢c, Spetal wall - It shows following structure s, 6) Septal wall a. Anteri , i) Fossa ovalis - Iti m oe Pectinate part is also Fat ovalis - It isa shallow depression fie he ariumprope isu ower part Iti the remnant of series of trar : ridges called musculi ecinata muscular muscu pectinati arising from. ~ |M |Tubercle ight pulmonary artery | Anulus in jor pulmonary vei superio" iat monary vein _ pp inferior PUl igh Fossa ovalis valve of IVC valve of coronary sinus remnant of septum secondum, «») Remains of foramen ovale - It is a small Ps yalvular opening present occasionally. sltlike va'vu” ‘The foramen ovale normally get occluded afer birth, but sometomes may persist. jy) AV. Node - At the base of the septal wall there is another pace maker of the heart called Atrio-ventricular (A.V.) node. CT Wray Introduction It is a triangular chamber of the heart receiving deoxygenated blood from the right atrium and pumping it to the lungs through pulmonary trunk. It has two surfaces: anterior and inferior. Iris Interior of the right ventricle Amuscular ridge called the supraventricular Crest or infundibulo-ventricular crest located between the tricuspid and pulmonary orifices divides the tight ventricle into 2 parts, 4) Outflowing part or infundibulum- It Inferior vena cava BE Pee stem Cardio Vascular $Y : superior vena cava Ascending aorta Pulmonary trunk Crista terminalis Musculi pectinati Tricuspid orifice Fig. Interior of right atrium is smooth and gives rise to the pulmonary trunk. | b) Inflowing part-It is rough due to presence of muscular’ ridges called trabeculae carneae. The inflowing part shows following structures, i) Trabeculae carneae -These are muscular ridges. They are of three types, + Ridges - Fixed elevations. * Bridges - Fixed at two ends and free in the centre. + Pillars or papillary muscles - There are three papillary muscles : anterior, posterior and septal, One end of the papillary muscle is attached to the ventricular wall and the other end is connected to the cusps of the tricuspid valve by chordae tendineae. The atrioventricular valves are kept competent by the active contraction of papillary muscles, so that during ventricular systole the valve remain tightly closed preventing blood going to the atrium.slar system Interior of the left atrium Cardio Vascu 5 of te . = The cusp ¢ : ii) Chordae mon a to the apice it shows following features, . ¢ are connected p , ie tricuspid sae cl a structure ; Musculi pectinati - These ate af the papillary etendinae oe are the Mi ae tendinac. Chordae eee ridges present only in the auricle n Use salled chore cusp; § ore they {c ‘a a ers even of free margin of cusp. ir atrium where they form network ar} of ys that they limit the amount Ss. py, Fossa hunata ~The Septal wall, ¢ the csp towards the ca ° junata which corresponds to the ¢ OWS foe iii) Moderator band - (Septomarginal of the right atrium. 1088 gy. . ding ae c i ular ridge exten F ' ; trabecula)- It is @ muse to the base of c. Opening of tributaries ~ The from the ventricular septum to ; i A efi a vapillary muse Itcontains the shows opening of four pulm tity ea ao along with few venae cordi: Onary Vej 4 right branch of A.V. bundle. e cordis minim; “its 2, The interior of the right ventricle shows ft Ventricle atrioventricular Ot Introduction two orifices a) Right X id by the tricuspid tricuspid orifice guarde' ‘ rricuspid orifice 8 It is an oxygenated chamber of 4 valve b) Pulmonary orifice guarded by the 7 he pulmonary valve. receiving oxygenated blood from th hea e ium thi i ba e le 4. The wal ofthe right ventricle is thinner than atrium throug the mitral valve ang le Ee it to the aorta through the aortic yal, lumps ve, that of the left ventricle . Exterior of the left ventricle 4. The cavity of the right ventricle is cresentic a. _ Ithas 3 surfaces : anterior, inferior and | in section. left En b. _ It forms the apex of the heart, : Introduction ¢. _ Italso forms the left border, left surg: Itis the left, upper, chamber of the heart. It of the sternocostal surface and a a Huber, diaphragmatic surface. of the receives oxyganeted blood from the lungs through four pulmonary veins and pumps Interior of the left ventricl le it to the left ventricles through bicuspid iineser of left ior of left ventricle show: Ss 2 or mitral opening which is guarded by the pe i U th bicuspid and mitral valve. a. Upper smooth part or Aortic vestib} j ible. It ae po oufowing part of the left ventricle tri smooth walled and nonm ooth wal luscular, it a, Itis quadrangular in shape. dre hap becomes continuous with” the ascend b. The posterior wall of the left atrium shi pore ti ; Tp aoe ugh aortic : ae . The anterior wall i i si is formed by the intera The left auricle proj f Projects terior “| ‘he infundibulum of th a 0 Ove E aa \e right with right surface facing 234 ta rface facing backwards.It has 3 - S mUSCUlAL And mon, Abranous part. The muscular part has the thick are the Yentricle a the right venricular ¢. ity, a part is postero-superi ness OF ges into ranous The human heart has tWo pairs |, Atrioventricular Valves, 2, Semilunar valves, Atrioventicular valve The opening... through which communicate with i atrioventricular orifices. They are gu: avalve called the atrioventriculay val are two in number : right and left, ») Right atrioventricular OF tricuspia valve {as the name implies, this valve is made up of three cusps and can admit the tip of three fingers. The three cusp are anterior, posterior and septal. » L oft atrioventricular or bicuspid valve oy Mitral valve - It is made up of two cusps -q large anterior and a small posterior cusp. The mitral cusps are smaller and thicker than those of tricuspid valve. are the arded by ve. They Structure Both atrioventricular valves are made up of, i) Fibrous ring - Cusps are attached to this ng. ii) cusp - Each cusp consists of a double fold of endocardium within which there is sme fibrous tissue. Each cusp is more or les triangular in shape. Base is attached lo the ring of fibrous tissue around the ioventricular orifice whereas the apex ‘al margins of the cusp give attachment *chordae tendinae. Each cusp has smooth BR Finre atrial surface and rough v Cardio Vascular system ntricular surfa iii) Chordae tendinae - These are delicat tendinous strands which connect the fr margins and ventricular surfaces of th cusps to the apices of the papillary mus They prevent eversion of free margins and limit the amount of ballooning of the cusp towards the cavity of the atrium iv) Papillary muscles - Th: ioventricular valves are kept competent by Contraction of the papillary muscles during Ventricular systole. active Importance The fi rst heart sound (Lub) is produced by closu re of atrioventricular valve. Function To maintain unidirectional flow of the blood oF to prevent backflow of the blood. The valves are closed during v by Apposition of atrial Margin, entricular systole surfaces near the Semilunar valves As the name implies, the shape of the cusp is Semilunar, The semilunar valves include the aortic and the pulmonary valve. Both valves have same structure, Structure i) Cusp - Each valve has three semilunar cusps. As the fibrous ring is absent, the Cusps are directly attached to the vessel wall. Each cusp is made up of a double fold of endocardium with some fibrous tissue enclosed in it. The cusps form small pockets with their mouths directed away from the ventricular cavity. ii) Nodule- The free margin of the cusp contains a central fibrous nodule (instead of chordae tendinae and papillary muscle). Ball:sot p, cresentic Cardio Vascular system iii) Lunule = Itis thin smooth ain part which extends from each S| margin of s 5 we f the cusp. They of the nodule to the base 0 contain very little connective tissue cusps, the vessel's d to form the aortic pulmonary sinuses. The coronary arteries ‘arise from the anterior and the left posterior iv) Opposite the are slightly dilate aortic sinuses. Importance Closure of the semilunar valves produces the second heart sound (Dup). Function Tomaintain unidirectional flow of blood or to prevent backflow of the blood. These valves are closed during ventricular diastole when each cusp bulges towards the ventricular cavity. Clinical aspect 1. _ Stenosis of valves -Fusion of the cusps leads to narrowing of the orifice called stenosis. e.g. mitral stenosis, aortic stenosis etc. 2. Incompetence or regurgitation - Dilatation of the orifice of the valve or stiffening of the cusps leads to imperfect closure of the valve producing backflow of the blood. This is called as incompetence or regurgitation. e.g. mitral incompetence or mitral regurgitation & aortic incompetence or aortic regurgitation. ere ng system of the Heart Introduction The normal heart contracts rhythm a rate of about 70 to 90 beats The thythmic process of contr tts occurrence in the vari slightly altered intervals the conducting i Sinotrial Node (SAN) Right Atrium Atrioventricular Node (AVN) Right Ventricle Right Bundle Branch (RBB) Fig. Conducting system of hear myocardium of the heart is ec en 7 initiation & conduction of the card alize, f lac Components mul The sinoatrial node, the atriovent the atrioventricular bundle, the by; bundle and the Purkinje fibres conducting system. Its fibres ar other myocardial fibres, Ticular ode ‘aNches g th, Constitute he © thinner tha Sino atrial node or S, A, Node known as the pace maker of th is horse-shoe shaped mass of cardiac muscle cells situated ; part of the sulcus terminalis, Th, Tise to spontaneous electrical the rate of 70/min which sprea the atrial musculature of both it to contract. “Its akg © heart, SPECialiseg n the upper € Node gives impulses at d throughout Sides causing Atrio ventricular Node or A.V. node- [tis Situated in the lower and dorsal part of the ti atrial Septum. Itis also capable of generating ppiises at a tate of about 60/min. Some impulses generated in the S.A. node bundle or Bundle of His - e A.V. node, crosses the AV. along the posteroinferioof the membranous part of the of sular septum. It is the only muscular ont een the atris yer ction between the atrial and Ventricular nc of “i or cuature fl aches of the atrioventricular bundle- al . jr ihe upper border of the muscular part Al ‘ ventricular septum, the Ay, bundle : jdes into right and left branches, a Right branch of AY. bundle- It passes jown the right side of the interventricular ‘et A large part enters the moderator vol to reach the anterior wall of the right ventricle where it divides into Purkinje fibres. ii Left branch of AN, bundle ~ It passes gown of the left side of interventricular septum and is distributed to the left ventricle after dividing into Purkinje fibres. purkinje fibres - They are also called as conduction myofibres. These fibres form a dense network deep to endocardium called Purkinje plexus. The entire musculature of poth ventricles are ramified by the Purkinje network. They are specialized for conduction Pie Cardiac arrhythmia « The A.V. bundle may system Cardio Vascular sy fail to transmit the impulse properly. In su h Case, alteration in the rhythmic contraction Of the ventricles occurs. This results in arrhythmia. Sometimes, complete block May occur resulting into total dissociation in the contractions between the atria and the Ventricles. Partial or complete block may also Occur in one of the bundle branches causing bundle branch blocks. The commonest cause for such blocks is atherosclerotic narrowing of the coronary arteries reducing blood supply to some part of the conducting system. Artificial pace maker can be fixed in patients with heart block. The pace maker has a pulse Generator that produces electrical impulses at a predetermined rate. ET ac Crh (Coronary circulation) The heart is supplied by two coronary arteries which are the branches of the ascending aorta, pot contraction. a. Right coronary artery. Importance b. Left coronary artery. Coronary distribution Right coronary artery Left coronary artery | Right atrium, * Most of the left atrium. 2 Part of the left atrium. * Most of the left ventricle. 3. Most of right ventricle except a small part onthe right of anterior interventricular groove. * Small part of right ventricle to the right of anterior interventricular groove. 4 Posterior 1/3 of interventricular septum. * Anterior 2/3 of interventricular septum. -A-node, A.V. node, A.V, bundle and some tof left bundle branch. * Some part of A.V. bundle, right and left bundle branches. : a aCardio Vascular system = Left coroner sperior “~y 2nd and 3rd parte of right coronary ‘artery branch Posterior and anterior interventricular branches Fig. Scheme to show coronary arteries = Right conus artery To sinoatrial node To part of left atrium To right atrium, To posterior one-third of interventricular septum To anterior wall of right ventricle To diaphragmatic surface of left ventricle Right marginal branch Te diaphragmatic surface of ant vente riaht ventricle Distribution of right coronary artery To left atrium Circumflex Occasional branch to sinoatrial node branch Left conus artery Left marginal artery To left atrium Diagonal Occasional artery continuation as Fig. Distribution of left coronary artery4 jiarities es a yital organ. : eter of COrol i fhe diameter of coronary artery js small eis tremendous anastomosis between rhe at o arteries ww ay are direct branches of. ascending arota, a the heart is the first organ of the ote " e which receives oxygenated blood, jor i c ue supply exactly half of the eat ; inc ronary arteries branch Tepeatedly ; epicardial surface of myocardium my then the final branches emege and = de perpendicular to subendocardial region. gubendocardial part of the heart suffers many times from hypoxia, therefore to compensate this, subendocardial part of the heart has dense capillary network. 10 === Ls Cardio vascular system Fast developement ofcollateral circulation. Existance of autoregulation “Normal coronary blood flow- 225 ml/min ue aS me Coronary sinus- The veins of the heart Predominantly drain into the coronary Sinus. It is the largest vein of the heart which is located in the left posterior Coronary sulcus. It is about 3 cm long. It Opens into the posterior wall of the right atrium. Following are the tributaries of the coronary sinus, 1. Great cardiac vein. 2. Middle cardiac vein 3. Small cardiac vein. 4. Posterior vein of the left ventricle. 5. Oblique vein of the left atrium. 6. Right marginal vein. ‘Oblique vein of left atrium Coronary sinus Great cardiac vein Left marginal vein | Small Right Middle ‘aiiac vein marginal vein cardiac vein Fe Scheme to show veins of the heart- anterior VieW ‘Oblique ——— vein of left atrium. Left marginal vein Coronary sinus Great cardiac vein Posterior vein of left vent le Right ‘Small Middle marginal vein cardiac vein cardiac vein Fig. Scheme to show veins of the heart- posterior view —Ea————— bn set scl teamed Cardio Vascular system 7. Anterior cardiac veins. 8, Venae cordis minimac (Thebesia s and yenae cordis tly into the right butaries drain into in veins ) Anterior cardiac vern minimae open direc! atrium, Rest of the tri the coronary sinus. Lymphatics of the Heart 1, Brachiocephalic lymph nodes. 2. Tracheobronchial lymph nodes. Nerve Supply of The Heart Sympathetic - Tyly T, segments of the spinal cord. These are cardioacceleratory means on stimulation they increase the heart rate and also dilate the coronary arteries. Parasympathetic - cardioinhibitory means on they slow down the heart rate. Boththesymphathetic-parasymphathetic from the superficial and deep of which Vagus. These are stimulation nerve cardiac plexuses, the branches runs along the coronary arteries to reach the myometrium . OTe eee emcee 1. Myocardial infarction due to complete blockage of a coronary artery. It is the common cause of sudden death. Angina pectoris -It is a ch by a temporary defic supply to the myoca due to spasm of the c pain can radiate arm, into the neck ai 8. 10. il. 12. arrest - This ter, m be complete i beating of the heart “OPPag 0 Coronary angiography - y, ofthe coronary vessels and th 'SUalisay by injecting contrast dye int et bran E i a0 them,“ chocardiography (E.C.G sonic cardiography - This Ut records the position and meet of the heart by echoes ob ultrasonic waves sent in it Med from Tachycardia - Increased heart Tat a te, Bradycardia - Decreased heart r. " ‘ate, Arrhythmia - Irregular heart rate, Palpitation - Consciousness of heartbeat. OF Ones Congestive cardiac failure (Cc Right sided heart failure due to po ei diastolic pressure in the i ‘ i ricles is called C.C.F. characterised = increased venous pressure, oedema 9, feet and breathlessness on exersion. 1 Cor pulmonale - Right sided hear failure due to lung disease. Inflammation of the heart can involve — more than one layer of the heart. Pericarditis is the inflammation of the is the inflammation of the is the inflammation of theRICARDIUM 8 jbroserous sac covering the heart IU |. roots of the great vessels. (aorta, , trunk, four pulmonary veins enae cavae) acatio” i — } is Jocated in the middle mediastinum It 4 the body of the sternum and the ehin' . a to 6” costal cartilages. components Fibrous pericardium- It is a conical sac made up of fibrous tissue. It is the outer layer. It continues above with the external layer (tunica adventitia) of great vessels. Below it is fused with the central rendon of the diaphragm. Anteriorly, it is attached to the posterior surface of the sternum by weak superior and inferior stemopericardial ligaments. Following are the functions of the pericardium, Functions - a) Helps to maintain general position of the heart. b) Itprevents over distension of the heart. 2, Serous pericardium -It is a thin, inner layer of serous membrane lined by mesothelium. It is made up of 2 layers, a) Perietal pericardium - It is an outer layer, It is fused with the fibrous pericardium. 5) Visceral pericardium (Epicardium)- Itis an inner layer. It is fused with the eet except along the cardiac grooves here it is separated from the heart by AB ix blood vessels Cardio Vascular sy stem The two layers are continuous with each other at the roots of the great ve Pericardial cavity There is a potential space between the parietal pericardium and the pericardium called the pericardial cavity It contains the pericardial fluid which acts as a lubricant to reduce friction between the beating heart and the outer layer of sac. About 50 ml of pericardial fluid is present in the pericardial cavity under normal circumstances. visceral Contents of the pericardium 1. Heart with cardiac vessels and nerves 2. Ascending aorta. 3. Pulmonary trunk. 4. Lower half of superior vena cava. 5. Terminal part of the inferior vena cava. 6. Terminal parts of the pulmonary veins. Pericardial sinuses Due to folding and bending of the heart tube, two potential spaces come to exist in the pericardial cavity called the pericardial sinuses. a) Transverse sinus - It is a horizontal gap between the arterial and venous ends of the heart tube. It is bounded Anteriorly, by the ascending aorta and pulmonary trunk. Posteriorly, by the superior vena cava and left atrium. On each side, it opens into the general cavity. |RST, “ Cardio Vascular system ores Serous eee arletal pericardium =] ‘Visceral pericardium Pericardial fluid Fibrous a Pericardium Fig. Pericardium b) Visceral pericardium ( is supplied by branches of | trunk and vagus nerves (para Anteriorly, by the left atrium. component). The visceral pe Posteriorly, by the parietal pericardium, not sensitive to pain. On each side, it opens into the rest of the Py TRRy] ead Le ity. pericardial cavity. 1. Pericarditis - Inflammation of the Blood supply - Branches of pericardium. It may be acute or chronic b) Oblique sinus - It is a narrow gap Picard behind the heart. It is bounded, lum) SYMpathetg Sympathetic Ticardium jc a) Internal thoracic artery. 2. b) Musculo phrenic arteries. c) Descending thoracic aorta. Pericardial effusion - Pericardial fluid is secreted in excess due to inflammation and get collected into the pericardial : ; cavity resulting into pericardial effusion, Venous drainage a) Pericardio phrenic veins (Tributaries of internal thoracic veins). Pericardio centesis - It is a process of pericardial fluid by passing € fluid can be drained by 5 or 6" intercostal I to apexbeat or in angle phoid process and left b) Tributaries of azygos venous system. Nerve supply a) Fibrous pericardium and pericardium are supplied by the | nerve. They are pain sensitive. a th the needle directed ; and to the left soa pleura or the lunp VESSELS i agscls are the channels through a js distributed to the body essels make up two closed hie’ the Y 3 s that begin and end at the ise of tube sit! gat pea : lmonary vessels - It transports ) qh from the right ventricle to the lungs we ko the left atrium. d and he gystemic vessels - It carries blood » eet ventricle to the tissues in all fro afibe body and then returns the blood gps oF te P eight ton so” ' : on their structure and function, blood sod Pe a are classified into, ve j Arteries 2, Veins 4, Capillaries slood from the heart is distributed to various sof the body by: arteries. Main and larger sreries branch into smaller arteries which iatum branch into still smaller arterioles. Arterioles supply blood thatiis rich in oxygen tp capillaries. Capillaries form capillary ted. From the capillaries, blood drains into yenules, Venules collect into smaller veins which inturn collect into larger veins. The venous blood of the upper parts of the body collect into the superior vena cava and the venous blood of the lower parts of the body collect into the inferior vena cava. both the venae cavae reach the heart. Depending upon. their properties, arteries ate classified into 3 types, ENF Cardio Vascular syste™ Large elastic arteries (Conducting arteries) They have many sheets of elastic fibres in their walls, So, they can expand when blood flows into them. They are close to the he art and receive blood under high pressure from the heart. e.g. The aorta and branches of the aorta, Medium muscular arteries (Distributins arteries)-They have more smooth muscle fibres in their walls. e.g. The brachial artery, radial artery, femoral artery. Small arteries -They have thick muscular walls and narrow lumen. Anastomosis Branches of an artery communicate with each other and branches of adjacent arteries. These communications are called anastomosis. Collateral circulation Ifa main artery is blocked gradually, blood flow increases in the anastomoses (Singular : anastomosis) and forms an alternate route called the collateral circulation. The blood supply to structures distal to the blockage is restored with collateral circulation. If blockage or occlusion is sudden, collaterals are insuficient. End arteries Arteries which do not anastomose with adjacent arteries are called end arteries or true terminal arteries. If such an artery is occluded, the structures supplied by it deprived of blood supply. e.g. Retina is supplied by end arteries. Veins also have 3 types. They have same properties. ‘a. Venules-Drain capillary beds and unite with Bill ««sett Cardio Vascular system form small veins. These m slightly larger lexus other venules to f eins unite to for small v 0 asually form t veins which v he venous p! 5 venous plexus and ries. They have directional blood The cephalic veins, femoral b. Medium Veins - Drain accompany medium art valves which permits unt flow towards the heart. ¢8: vein, basilic vein, saphenous vein etc. have number of bundles Large veins -They hi ' i in their of longitudinal smooth muscles 1 walls.e.g. Superior vena cava. Venae comitantes Deep arteries are usually accompanied by not a single vein but by a pair of veins called as venae comitantes. The two venae comitantes communicate with each other by means of cross channels. Because of this arrangement, a counter-current heating system is established. The blood returning from various parts of the body in the veins is cooler and the blood flowing in the arteries is warmer. The close proximity of venae comitantes and the cross channels to the artery allows the cooler blood to be warmed as it returns to the heart. The venae comitantes, along with the artery are usually enclosed in a vascular sheath, which is not very yielding. When blood flows through the artery in such a system, the artery expands and compresses the veins, The veins, though expandable due to the Testriction posed by the sheath are stretched and flattened. This aids in pushing the blood up the veins, facilitating venous return, Capillaries These are the smallest and most nun of blood vessels forming n between the arterioles a “I Structure of Blood Vessels Y(t gy) b. form a network called the gq, Exchange of material between M4" p, in the capillaries and the extracey® bio takes place in the capillary beg ii nt of the total blood volume ig jn, th Sbou 3 capillaries at any given time, e 8 Stem The capillary distribution Varies metabolic activity of body tissues, With the a) Tissues such as skeletal musc|e i kidney have extensive capillary ae ang they are metabolically active ang i us abudant supply of oxygen and Dutien an b) Other tissues such as connecity have less abundant supply of ea tissue. 7 fp ‘atieg, c) The epidermis of the skin, the |, cornea of the eye have complete capillary network. ens an, lack of The walls of an artery and vein. Consist layers, ae Tunica intima (Tunica interna). |t jg the inner most layer. It is made up of sim i squamous epithelium surrounded a i connective tissue basement membrane te elastic fibres. Tunica media - It is the middle layer. It is usually the thickest layer. It has circularly placed smooth muscles and elastin fibres Contraction of these smooth miles causes narrowing of the lumen called vasoconstriction & relaxation increases the Size of the lumen called vasodilatation, so a to regulate blood flow and blood pressure ‘Tunica adventitia) It is vhich attaches the vessel e. It is made up of ing amount ofe of blood vessels wo. struct walls of the veins are thinner than The arteries and the lumina are larger. spose = adventitia is thicker than the The eae and elastin is much less. In runic ™ the tunica intima folds on itself to witiotreaay valves. These valves ensure i ectional flow of blood towards the ui peat BR Fixe: Vasa vasorum Cardio Vascular system In the tunica adventitia of large v there are small vessels which supply the Outer portion of the vessel wall called as vasa vasorum. The inner portion of vessel walls of large vessels and comple vessel walls of smaller vessels derive their nourishment from the luminal blood itself Vasa vasorum may be branches of the same Parent vessel or adjacent vessels: Structure of capillary The wall of a capillary has a single layer of endothelium surrounded by a basal lamina The cells of endothelium are connected to each other by tight junctions. The gaps in between such junctions are called intercellular clefts and serve as passage from and to the blood in the capillary. ARTERIAL SYSTEM i The Trunk gop I Arteries of Puce Pan hs The pulmonary trunk arises from the right ventricle. The junction between the two is guarded by the pulmonary valve. The trunk ‘uns upwards and backwards and ends by dividing into the right and left pulmonary arteries. Bifurcation of the pulmonary trunk lies below the arch of the aorta. 1, Right pulmonary artery ltarises from the upper end of the pulmonary unk. It has a long intrapericardial course 4s compared to the left pulmonary artery. Then it runs to the right to reach the hilum of the right lung. It ends by dividing into ‘Wo main branches, ) Upper branch- It is smaller and supplies — iF Fig. Pulmonary trunk the upper lobe of the right lung. ii) Lower branch - It is larger and supplies the lower lobe. Each of these branches subdivid es to accompany the segmental branches of the corresponding bronchi and hence reach the bronchopulmonary segments. Bill »:Cardio Vase ular system 2. Left pulmonary artery the upper end of the pulmonary Jy the hilum Trartees from trunk and funs to the of the left hung. It end hes that arc dist ang equally Jeff to reac js by dividing ributed to the two into two main brane Jobes of the left I The heart distributes blood to the entire hody through an elaborate arterial tree. The ‘main stem’ of this tree 1S called the aorta. It ¢ left ventricle and the junction between them 1s guarded by the aortic valve. It is the largest artery 1n the body. At its gin, it is about 3 cm in diameter. arises from th ori Parts - For description purpose the aot divided into, a) Ascending aorta, rta is b) Arch of aorta, c) Descending aorta s further divisible into the Descending aorta I the abdominal aorta. descending thoracic aorta &ll Ascending aorta It is about 5 cm in length and 3 cm in diameter, It is enclosed in the pericardium. It arises from the left ventricle. Just above the aortic valve, the wall of the ascending aorta is marked by three dilatations called the aortic sinuses : one anterior and two (ri ight and lefi) posterior. The anterior aortic sinus gives origin to the right coro artery and left posterior wai sinus oa origin to the left coronary artery. The right posterior aortic sinus is noncoronary sinu It becomes continuous with the arch o at the level of sternal angle, da Branches Right coronary artery, Left coronary artery Arch of aorta It is the continuation of the age It is located in the superior *Nding 4, behind the lower half of the init the sternum. It begins at the leva ta . angle, arches over the root of a fe Step ung The diameter of arch of aorts its origin and 2 cm near its ra ies At the level of lower border stn T,, it continues as descending ‘ Vetter, junction with the descending ple At it ee called the aortic ae Stal seen which is immediately followed 2 is by 4 dilatation. Branches Brachiocephalic trunk- further divig i) Right common carotid artery. ed int ii) Right subclavian artery, Left common carotid artery. Left subclavian artery. Occasionally, a small arte S Ty supplyi thyroid gland called the Rea hy 4 ima may arise from the arch of aorta. and aorta el f are! a . continuation of arch of aorta, It is ra ‘ ye into two parts, isi! acic aorta. , Thor apdom aorta. 5 poracie aorta continuation of the arch of aorta. It nis : sie posterior mediastinum. It begins jes - jower border of vertebra T, and ds i front of the thoracic vertebrae all passing from the left side towards median plane. At the level of lower of vertebra T,,, it passes through the fice of the diaphragm to enter the here it becomes continuous with inal d th porder gortle orl pdomen W Fe abdominal aorta. pranches 1, Nine pairs > Subcostal artery on each side. 3, Two left bronchial arteries(upper &lower) 4, Oesophageal branches. 5, Pericardial branches. of posterior intercostal arteries. BN Five Abdominal aorta Cardio Vascular system It is a continuation of the thoracic art It begins in the midline at the aortic open'n# of the diaphragm opposite vertebra Tl descends in front of the lumbar vertebrae It terminates in front of vertebra L, by dividing into two terminal branches called the common iliac arteries. Branches Ventral- 1. Coeliac trunk. 2. Superior mesenteric artery. 3. Inferior mesenteric artery Lateral- 4, Right and left inferior phrenic. 5. Right and left middle suprarenal 6. Right and left renal arteries. 7. Right and left gonadal arteries. Dorsal - 8. Four pairs of lumbar arteries. 9. Anunpaired median sacral artery. Terminal-10. Right common iliac artery. 11. Left common iliac artery. 1. Coronary arteries 6, Mediastinal branches. 7, Superior phrenic arteries. "BRANCHES FROM [ARCH OF AORTA, Pesce Unpaired branches. ‘arising from the ventral aspect: Coeliac trunk: Paired branches arising from the lateral aspect: Inferior phrenic artery es Middle suprarenal artery mesenteric artery Renal artery Paired branches arising {rom the front: ‘Teatieular or ovarian artery Paired branches arising from the posterior aspect! ‘Lumbar arteries (usually four pais) Paired terminal branches: - Fig, Abdominal aorta and its branches | Fig. Thoracic aorta and its branches|| The coronary arteries supply blood to the Cardio Vascular system heart. They arise from the ascending aorta. Both arteries runs in coronary sulcus. a) Right coronary artery- It is smaller than left coronary artery. It arises from the anterior aortic sinus, It ends by anastomosing with the left coronary artery Branches Large branches - i) Marginal ii) Posterior interventricular, Small branches - i) Nodal in 60 % cases ii) Right atrial iii) Infundibular iv) Terminal. b) Left coronary artery It is larger than the right coronary artery. It arises from the left posterior aortic sinus. It ends by anastomosing with the right coronary artery. Branches Large branches - i) Anterior interventricular ii) A branch to the diaphragmatic surface of the left ventricle. Small branches - i) Left atrial ii) Pulmonary iii) Terminal. 2. Brachiocephalic trunk Thisis the first branch of the arch of the aorta. Its origin lies more or less in the median plane, in front of the trachea. From here, it runs upwards and backwards and then winds around the trachea to reach the right side of the trachea, It ends behind the right sternoclavicular joint by dividing into the tight common carotid and right subclavian arteries. Branches a, Right common carotid artery. . Right subclavian artery. TT | Common carotid & Subela, Vii [Note : described in the neyy tt Broy Coeliac trunk » tieg It is the artery of the foregut the front of the abdominal agi the aortic opening of the level ofthe dise between vergh 2 L,. The coeliac trunk is only cee ang inch long. It supplies al] cera hal a foregut that lie in the abdomen like OF the a) The lower end of the Oesoy stomach and upper part of the to the opening of the common the liver c) the spleen 4) the gy the pancreas. s re Dy a J diaphra 4 belo, Us, duoden the e im. bile duet.” Teale part op Branches It ends by dividing into 3 terminal branches 1. Left gastric artery. 7 2. Hepatic artery. 3. Splenic artery. a) Left gastric artery The left gastric artery is the smallest of the three branches of the coeliac trunk, Ttruns upwards and to the left behind the lesser sac to reach the cardiac end of the stomach, Then it enters the lesser omentum and nun. downwards along the lesser curvature, |, ends by anastomosingoe pageal branches at the cardiac oes" gomach ii) numerous gastric ne along the lesser curvature of the artery er nr forwards and to the nind the lesser sae to reach the upper duodenum. Here, it enters the pdt ent reaching porta hepatis. It set ve, by dividing into right and left nal ‘ic pranches- ranches” gastroduodenal artery. , Right gastric artery. : upraduodenal artery. il in) cystic artery. ) Right and left hepatic branches, y) Rig! g splenic artery ris the largest branch of the coeliac trunk. It uns horizontally to the left along the upper jorder of the pancreas behind the lesser sac. itreaches the hilum of the spleen where it {vides into 5-7 splenic branches. Branches - i) Numerous pancreatic branches. ii) 5-7 Short gastric arteries. ili) Left gastroepiploic artery. iv) Splenic branches which enter the hilum af the spleen. . Superior mesenteric artery ltisthe artery of the midgut. It arises at the level of vertebra L, behind the body of the Pancreas, Iem below the coeliac trunk. It “plies all the derivatives of the midgut I ea) lower part of the duodenum below the Cardio Vascular system Fig. Superior mesenteric artery Opening of the common bile duct b) jejunum c) ileum d) appendix e) caecum f) ascending colon g) right 2/3 of transverse colon h) lower half of the head of the pancreas It terminates in the right iliac fossa by anastomosing with a branch of the ileocolic artery, Branches - It gives off five sets of branches 1. Inferior pancreatico duodenal 2. Jejunal and ileal 3. Right colic 4. Teo colic 5. Middle colic a) Inferior pancreatico duodenal artery It is the first branch of the superior mesenteric artery. It divides into anterior and posterior branches which run in the pancreaticoduodenal groove, supply the head of the pancreas and the duodenum. It ends by anastomosing with the superior pancreaticoduodenal artery. b) Jejunal and ileal branches TT we aest A120 1S number and arise These are abou » of the superior mesenteric % Inferior mesenteric _— eee x between the two layers of a owns the gut The branches ach other to form a series hich numerous straight arise to supply the gut eystem Cardio Vasculat §Y artery respectively Its the artery of the hindgut, fg, | Atigg, the front of the abdominal aorta be - part of the duodenum at the level of / e the termina Verte L, above the termination of the q ¥ eh aorta. It supplies all the derivatives Minal 8 fie the mesentery t of ‘ anastomose with ms of arches from w arteries (vasa recta) ¢) Right colic artery hindgut like a) left 1/3 of the fis the ing 81 It arises from the right side of the superior colon b) descending colon ¢) sigmoid . " ee nteric artery at about its middle. It d) rectum e) upper part of the anaj een reser y passes to the right to reach the ascending Branches - . colon. It terminates by dividing into descending and ascending branches which 1 Left colic artery (superior left Colic art anastomose with the ileocolic and middle 2.Sigmoid arteries(inferior leftcolic an ety) .. Tes colic arteries ee ae are 3,Superior rectal arteries. 8) supplies the upper 2/3 of the ascending i ; colon and the right flexure of the colon. a) Left colic artery (superior left colic artery 4) Heo colic artery Itis the first branch of the inferior Mesenter 5 de of the 1 artery. It runs upwards and to the Teh os It ates from the right ‘ eo oe ew : divides into an ascending and a ane of the superior mesenteric artery. renee Varcendineskean. @ downwards and divides into superior and : branch enters the inferior branches. The superior branch anastomoses with the right colic artery and the inferior branch. anastomoses with the termination of the superior mesenteric artery. The inferior branch of ileocolic artery gives out following branches i) an ascending (colic) branch to the ascending colon ii) anterior and posterior caecal branches to the caecum iii) an appendicular branch iy) the ileal branch to the terminal portion of the ileum. ©) Middle colic artery It arises from the right side of the superior Mesenteric artery just below the pancreas, It runs downwards and forwards in the | transverse mesocolon, It divides into a right | ; ranch which with the Tight colic artery acolon and anastomose with the eatery: THe descending branch coll’ th the highest sigmoid artery, ose “a arteries (inferior left colic arteries) ye a > to 3 number. They pass of * oad to the left to reach the wt “7100 and anastomose with each oid © mn the lower part of the marginal (0 107" per most branch anastomoses g branch of the left colic ly descending colon and Fal a gescendiny ih ey supe wf moid colon. ¢ sie superior rectal artery Q 3 ‘infer 5 j continuation of the inferior mesenteric us se peyond the root of the sigmoid a lon. It descends in the sigmoid on to reach the rectum. Opposite or it divides into right and left bra 8; > : a n descends one on each side ranches whic! rectum. phrenic arteries (right and left) They arise from the abdominal aorta just spove the coeliac trunk. Each artery runs d laterally on the corresponding ons of the diaphragm, medial to the suprarenal gland. Each artery gives off 2 to 3 superior suprarenal arteries and is then distributed to the diaphragm. 4, Middle suprarenal arteries (right and left) ofthe «Inferior upwards an These small arteries arise at the level of the superior mesentericartery. Each passes laterally & slightly upwards over the corresponding cnis of the diapharagm close to the coeliac ganglion. The right artery passes behind the inferior vena cava and the left artery runs with the splenic artery above the pancreas. 4, | Renal arteries (right and left) Tt e . i a hese are large arteries which arise from 10. Gonadal arteries (Testicular or ovarian art BRI Fixee:- the abdominal aorta just below th of origin of the superior mesenteric artery: They pass laterally to reach the hilus of the corresponding kidney. Each artery gives off the inferior suprarenal and ureteral branches and is then distributed to the kidney. Cardio Vascular system e level ery) These are small arteries that arise from the front of the abdominal aorta a little below the origin of the renal arteries. Each artery runs downwards and slightly laterally on the psoas major. a) Testicular artery at the deep the inguinal the testis, it It joins the spermatic cord inguinal ring and traverses canal. At the upper pole of breaks up into branches which supply the testis and the epididymis. b) Ovarian artery Inferior phrenic artery External iliac artery Inguinal canal Wha) Fig. Lateral branches of abdominal aorta (a-superior, b-middle, c-inferior)«80 ac vessels ry ligament Cardio Vascular system mal ilia at the the suspenso' rs the broad ligament ach the 1t crosses the exter pelvic brim to enter ofthe ovary. Itthus ente yw the uterine tube to re and runs belo’ J ovary through the mesovarium. The artery gives @ branch which continues medially ith the uterine artery and to anastomose W supplies twigs t0 the uterine tube and to the pelvic part of the ureter. 11. Lumbar arteries Four pairs of lumbar arteries the abdominal aorta opposite the bodies of upper four lumbar vertebrae. They pass laterally deep to the psoas major and quadratus lumborum muscle. They end in small branches between the transversus abdominis and internal oblique muscles. arise from Each artery gives off dorsal branch which arises at the root of the transverse process. The dorsal branch gives offa spinal branch to the vertebral canal and then runs backwards to supply the muscles and skin of the back. 12. Median sacral artery Itarises from the back of the abdominal aorta Right crus of diaphragm, Fig. Posterior branches, ofal » ihn just above the bifurcation of th runs downwards to end in front “th It supplies the rectum and ap, ; the iliolumbar and lateral sac, aon, a f the Co ang AStOM Og. Vx : = Tal arterie. "th Common iliac arteries (right ay 1 id These are the terminal bran, i) abdominal aorta arising in fae L,. On each side it passes down, ra laterally and ends in front of tee S ang joint by dividing into the SaCroiliag { Of verte ® a) External iliac artery. b) Internal iliac artery, a) External iliac artery It is larger of the two terminal bra the common iliac artery. It nd of of sacroiliac joint and then pa SiN front the midinguinal point a deep tg continuous with the femoral —. b) Internal iliac artery : It supplies almost all pelvic Viscey in front of sacroiliac joint and : upper border of greater sciatic not h, it divides into anterior and Poster a Ps branches of the anterior Ea. 7 vision are given in the following be | a. Tt starts TUNS to the Internal iac arteryBEI ie Cardio Vascular systerr Branches of Posterior division Superior gluteal j . ranches of Anterior division Hm periot V esical Inferior gluteal Obturator Internal pudendal Ascending aorta Brachiocephalic trunk Arch of aorta Left common carotid Left subclavian Descending thoracic aorta Descending abdominal aorta Left Common iliac Right Common iliac Right Right Left Left teal iliac Internal iliac External iliac Internal iliac } i i Left Ante: Posterior ‘Anterior — Posterior nterior ste! Femoral artery division _ division Right ter 2 division emoral artery division0 | Cardio Vasculat system Group He Arteries of Head and Neck The main Blood supply to the structures af the fond and neck region is ftom the common carotid and subclavian artertes. 1. Common carotid arteries (right and left) ‘The tight common carotid artery 18 @ branch of the brachiocephalic trunk and the left common carotid artery is a direct branch of arch of aorta, Common caratid artery passes upwards in the carotid sheath along with the internal jugular vein and vagus nerve. Branches At the level of the upper border of the thyroid cartilage the artery ends by dividing into, a) External corotid artery b) Internal carotid artery — External carotid artery — intemal carotid artery Left common carotid artery Ascending cervical artery Thyroid gland — Inferior thyroid artery Vertebral artery — Fig. Common carotid arteries Carotid sinus The termination of the common carotid artery or the beginning of the internal carotid artery show a slight, fusiform dilatation called the carotid sinus. In this region the tunica media is thin but the tunica adventitia is relatively thick and receives a rich innervation fom the Function - It acts as a baroreceptor and. glossopharyngeal and sympathetic nerves, | controls the blood pressur Carotid body It is a small, oval, teddigh.+ vascular structure situated |. bifurcation of the commen ateitia It receives a rich nerve from the glossopharyn; from the vagus and sympathos, t @ Function - It acts as a chemore, Os CEPA» responds to chang in the oxy.” carbon-di-oxide content of the bj i" ; ood a) External carotid artery It is one of the terminal branch : €8 common carotid artery. f the It begin: c neck at the upper border of "ty * the cartilage opposite the interven between vertebrae C, and C,. Itis the dise artery supplying the structures in the 4 and face. It terminates behind the a the mandible by dividing ino maxilig superficial temporal artery, TY and Branches - It gives off 8 branches, Anterior - 1. Superior thyroid artery. 2. Lingual artery, 3. Facial artery, Posterior - 4. Occipital artery.s, Po psterior auricular artery, , Ascending pharynges Pg geal artery i 9, Max ary artery, ) al’ an 8. superficial temporal arte carotid artery e e two terminal bran ‘ ches os -af0 vid ate Itbegins at e 4 i 5 the upper ng the yroid cartilage oppo : ral disc between Wit c, ends inside the cranial cavity by e brain. It is the principal es , and the eye. It also rales we nt ose of description, it is divided into 4 sm ca "cen ical patt - This part lies in the neck. This part lies within the 4 petrous part - tr ous temporal bone. 3, cavemous part - This part lies within the cavernous sinus. 4, ated part - This part lies jn relation to the base of the brain. pranches Cervical Pp? ches arise from this ut its init || part shows carotid sinus. ic branches b) Prerygoid bral Cavernous P a) Cav' ous nches to the jgemil anglion b) ‘Superior and inferior ypophysee! ranches. Cerebral part- a) Ophthalmic artery: b) Anterior cerebral artery: ¢) Midd! dle cerebral artery: Mt bones and meninges. For the 2 Si i subclavian artery (right and left) NY: — Ca ~ rio \ Vascular sorte he rab al artery Not eho ti unicating ; artery Braces 0 wns conv geminal gangion Carotcatymparic branches to middle ear ea caro airy ig. Scheme to show internal mp carotid artery & its b ‘osterior cor a mmunicating artery nterior choroidial artery Ttisth BE eecyanens 8 Theright :. es artery is @ branch of the brachio »phalic artery and the left subclavian artery isa direct branch of the arch of aorta. It also supplies a considerable part of the neck and olan Tt passes Ove" behind the clav i to enter the UPPeT part of the axilla. At the cuit border of the ye rib scalenus anterior and divides it i Branches The subclavia! i vertebral artery: n artery gives © 2, Internal thoracic arte £3 branches: ee Thyrocervie® a) Inferior arc artery: b) suprascapulat® artery: c) Supe! erficial cervical arter ries °2 branches 4, costo gives off 2 rior intel ercosta a) Supe pall rv! vical trunk-¢! tal artery