CARDIOVASCULAR SYSTEM Khaleel Alyahya, PhD, MEd King Saud University Schl f Medicine @khaleelya
OBJECTIVES At the end f the lecture, students shuld be able t: Identify the cmpnents f the cardivascular system. Describe the Heart in regard t (psitin, chambers and valves). Describe the Bld vessels (Arteries, Veins and Capillaries). Describe the Prtal System. Describe the Functinal and Anatmical end arteries. Describe the Arterivenus Anastmsis.
CONTENT Pump: HEART Netwrk f Tubes: BLOOD VESSELS
FUNCTIONS It is a transprtatin system which uses the bld as the transprt vehicle. It carries xygen, nutrients, cell wastes, hrmnes and many ther substances vital fr bdy hmestasis. It prvides frces t mve the bld arund the bdy by the beating Heart.
THE HEART It is a hllw, cne shaped muscular pump that keeps circulatin ging n. It is the size f hand s fist f the same persn. It has: Apex Base Surfaces: Diaphragmatic & Sterncstal Brders: Right, Left, Inferir.
LOCATION OF THE HEART It is lcated in the thracic cavity in a place knwn as the Middle Mediastinum between the tw pleural sacs. Enclsed by a duble sac f serus membrane (Pericardium). 2/3 f the heart lies t the left f median plane. The uter wall f the heart is made up f three layers: Epicardium. Mycardium (muscle f the heart). Endcardium.
CHAMBERS OF THE HEART ATRIA: They are tw (Right & Left). Superir in psitin. They are the receiving chambers. They have thin walls. The upper part f each atrium is the Auricle. The Right Atrium receives the venus bld cming t the heart. Left Atrium receives arterial bld cming frm the lungs.
CHAMBERS OF THE HEART VENTRICLES: The inferir chambers. They are tw (right & left). They have thick walls. They are the discharging chambers (actual pumps). Their cntractin prpels bld ut f the heart int the circulatin.
VALVES OF THE HEART The heart has FOUR VALVES: Tw Atri-Ventricular valves. One Artic Semilunar valve. One Pulmnary Semilunar valve.
VALVES OF THE HEART Atriventricular Valves: Valves between atria & ventricles. They allw the bld t flw in ne directin frm the atria t the ventricles. Right AVV (Tricuspid). Left AVV (Bicuspid).
VALVES OF THE HEART Semilunar Valves (Artic & Pulmnary): Between the right and left ventricles and the great arteries leaving the heart. Artic Semilunar Valve Pulmnary Semilunar Valve They allw the flw f bld frm the ventricles t these arteries.
BLOOD VESSELS Arteries: Thick walls. D nt have valves. The smallest arteries are arteriles. Veins: Thin walls. Many f them pssess valves. The smallest veins are venules. Capillaries Cnnect arteriles and venules. Help t enable the exchange f water, xygen and ther nutrients between bld and the tissues.
ARTERIES They transprt bld frm the heart and distribute it t the varius tissues f the bdy thrugh their branches. Carry xygenated bld away frm the heart. Tw Exceptins: The pulmnary arteries. Carries dexygenated bld frm the heart t the lungs. The umbilical arteries. Supplies dexygenated bld frm the fetus t the placenta in the umbilical crd.
ANASTOMOSIS It is the cnnectin f tw structures. It is the jining f terminal branches f the arteries.
END ARTERIES It is the artery that is the nly supply f xygenated bld t a prtin f tissue. Arteries which d nt anastmse with their neighbrs are called end arteries. Examples: Splenic artery. Renal artery.
They transprt bld back t the heart. The smaller veins (Tributries) unite t frm larger veins which cmmnly jin with ne anther t frm Venus Plexuses. Carry dexygenated bld tward the heart. Tw Exceptins: the pulmnary veins. receive xygenated bld frm the lungs and drain int the left atrium f the heart. the umbilical veins. VEINS carry xygenated bld frm the placenta t the grwing fetus.
DEEP VEINS (VENAE COMITANTES) Tw veins that accmpany medium sized deep arteries Vena cmitans is Latin fr accmpanying vein. They are fund in clse t arteries s that the pulsatins f the artery aid venus return. Venae cmitantes are usually fund with smaller arteries, especially thse in the limbs. Larger arteries d nt have venae cmitantes. They usually have a single, similarly sized vein.
CAPILLARIES Micrscpic vessels in the frm f a netwrk. They cnnect the Arteriles t the Venules. They help t enable the exchange f water, xygen and many. ther nutrients between bld and the tissues.
ARTERIOVENOUS ANASTOMOSIS Direct cnnectins between the arteries and veins withut the interventin f capillaries. Fund in tips f the fingers and tes.
PORTAL CIRCULATION SYSTEM Prtal Venus System ccurs when a capillary bed pls int anther capillary bed thrugh veins, withut first ging thrugh the heart. Veins leaving the gastrintestinal tract d nt g direct t the heart. They pass t the Prtal Vein. This vein enters the liver and breaks up again int veins f diminishing size which ultimately jin capillary like vessels (Sinusids).
SUMMARY The cardivascular system is a transprting system. It is cmpsed f the heart and bld vessels. The heart is cne shaped, cvered by pericardium and cmpsed f fur chambers. The bld vessels are the arteries, veins and capillaries. Arteries transprt the bld frm the heart. The terminal branches f the arteries can anastmse with each ther freely r be anatmic r functinal end arteries. Veins transprt bld back t the heart. Capillaries cnnect the arteries t the veins. The prtal system is cmpsed f tw sets f capillaries. The veins frm the GIT g first t the liver thrugh the prtal vein.
Review Questin # 1 Which ne f the fllwing is NOT true? 1. Right atria receive bld frm the bdy. 2. The valve between right atrium and right ventricle called Bicuspid. 3. Left ventricle discharging bld t the bdy. 4. Right ventricle receives bld frm right atrium. 5. Valves allw bld t mve ne way nly.
Review Questin # 2 Which statement f the fllwing is TRUE? 1. Arteries transprt bld frm the heart t the bdy. 2. Arterivanus anastmsis fund in tips f the fingers and tes. 3. Capillaries cnnect the Arteriles t the Venules. 4. Anastmsis is the jining f terminal branches f the arteries. 5. Veins leaving the gastrintestinal tract d nt g direct t the heart.
Questins!