Anatomy and Physiology The cardiovascular system


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Anatomy and Physiology The cardiovascular system

  1. 1. The Cardiovascular SystemMr. HunterAnatomy and Physiology
  2. 2. Anatomy and Physiology05/06/2013• Objectives• SWBAT• Understand the function and the importance of theCardiovascular System• Analyze the structure of the heart• Examine circulation function and dynamics• Bell Ringer: What is the function of a vasomotor mechanism?
  3. 3. The Cardiovascular System• The system that supplies our body’stransportation needs is thecardiovascular system.• Provides the replenishment ofoxygen water and nutrients to cells• Provides a means of removal ofwaste products from cells.• Circulation of the blood is critical tomaintaining homeostasis.
  4. 4. The Heart• The heart is located between thelungs in the lower portion of themediastinum.• 2/3 of the mass of the heart islocated on the left of the thoraciccavity and 1/3 is located on the right.• The heart is a triangular shapedorgan, shaped and sized roughly likea closed fist.• The apex which is the blunt pointed, lower edge of the heart lies on thediaphragm pointing toward the left.• The apical heart beat is locatedbetween the 5th and 6th rib along themidline of the left clavicle.
  5. 5. The Heart• The heart is positioned in thethoracic cavity between the sternumin front and the bodies of thethoracic vertebrae behind.• Due to its location, the heart can becompressed or squeezed by theapplication of pressure to the lowerbody of the sternum using the heelof the hand.• CPR allows the temporarymaintaining of blood flow in theevent of cardiac arrest.
  6. 6. The Heart• The heart is a hollow organ. Apartition divides it into right and leftsides.• The heart contains four cavities, orhollow chambers.• The two upper chambers are calledatria. The two lower chambers arecalled ventricles.• The atria are smaller than theventricles and their walls a lessmuscular. They are often called thereceiving chambers.• Blood exits from the ventricles intoarteries – pulmonary and aorta. Theventricles are referred to asdischarging chambers.
  7. 7. The Heart• The wall of each heart chamber is composedof cardiac muscle tissue called myocardium.• The septum between the atrial chambers iscalled the interatrial septum.• The septum between the ventricles is calledthe interventricular septum.• Each heart chamber is lined by a thin layer ofsmooth muscle endocardium.• Inflammation of this layer is calledendocarditis.• The covering of the heart is called thepericardium. It consists of a parietal andvisceral layer with lubricating fluid in between.• The inner layer = visceral pericardium(epicardium) Fits like the skin of an apple.• The outer layer = parietal pericardium.• Fits around the heart like a loose fitting sack.• Pericarditis = inflamed pericardium
  8. 8. Review 04/15/2013Anatomy and PhysiologyChapter 121. What is the name of the system that provides our body with itstransportation needs?2. Why is adequate circulation critical to the body?3. Where is the heart located?4. In which cavity and on which side is the greatest amount of mass fromthe heart located?5. What portion of the heart lies on the diaphragm and points towards theleft?6. Where would a doctor or nurse place a stethoscope to listen to yourapical heart beat?7. What bony structures lie anterior and posterior to the heart?8. What are the names of the chambers of the heart?9. Describe myocardium, endocardium and pericardium.
  9. 9. Heart Action• The heart serves as a muscularpumping device for distributingblood to all parts of the body.• Pulmonary circulation and Systemic.• Contraction of the heart is calledsystole.• Relaxation of the heart is calleddiastole.• When the heart beats, the atriacontract first (atrial systole), forcingblood into the ventricles.• Once filled, the two ventriclescontract (ventricular systole) andforce blood out of the heart.
  10. 10. Heart Valves• The two valves that separate the atrialchambers above from the ventricularchambers below are called theatrioventricular valves (AV).• The right AV valve is called the tricupsidvalve. It consists of three leaf-like valvecomponents.• The left AV valve is called the bicupsid ormitral valve. It consists of two leaf-like valvecomponents.• Both AV valves prevent the backflow ofblood into the atria when the ventriclescontract.• Stringlike structures called chordaetendineae attach the AV valves to the wallsof the ventricles via papillary musclesextending from the floor of the ventrricles.
  11. 11. Heart Valves• The semilunar valves (SL) valves are locatedbetween the two ventricular chambers andthe arteries that carry blood away from theheart when systole occurs.• The ventricles contract at the same time likethe atria. The two SL valves open and closeat the same time.• The pulmonary SL valve is located at thebeginning of the pulmonary artery andopens to allow blood to enter pulmonarycirculation. The valve closes to preventsbackflow of blood into the right ventricle.• The aortic SL valve is located at thebeginning of the aorta. The valve opens toallow blood to enter systemic circulation. Itcloses to prevent backflow of blood fromthe aorta into the ventricles.
  12. 12. Heart Sounds• Two distinct sounds can be heard onthe anterior chest wall.• They are described as the lub dupsounds.• The first lub sound is the result ofthe abrupt closure of the AV valvesas the ventricles contract.• The closure of the AV valves duringventricular systole prevents bloodbackflow into the atrial chambers.• The second sound , dup is theclosing of both the SL valves duringventricular diastole.
  13. 13. ReviewAnatomy and Physiology04/16/20131. What are the two circulatory paths that the heart pumps blood to?2. What is the contraction of the heart called?3. What is the relaxation of the heart called?4. What is the name of the AV valve that separates the right atrium fromthe right ventricle?5. What is the name of the valve that separates the left atrium from the leftventricle?6. How many leaf like components does the right AV valve have incomparison to the left AV valve?7. What are the names of the valves located between the ventricles and thearteries that carry blood away from the heart?8. What function do chordae tendineae have?9. What are papillary muscles?10. If you only heard the lub sound on the anterior chest wall, whatstructures may be defective within the heart?
  14. 14. Blood Flow Through TheHeart• The heart acts as two separatepumps.• The right side of the heart pumpsblood into the pulmonary system.• The left side of the heart pumpsblood into the systemic circulation.• Blood enters the right atriumthrough two large veins called thevena cava. The superior and theInferior vena cava provides the rightatrium with blood.• Venous blood lacks oxygen.Therefore, veins normally transportdeoxygenated blood and arteries willtransport oxygenated blood.
  15. 15. Blood Flow Through TheHeart• The blood leaving the right ventricleis deoxygenated. However it entersthe pulmonary circulation via thepulmonary arteries.• It is returned as oxygenated blood tothe right atrium via four pulmonaryveins.• The blood returning to the leftatrium crosses the mitral valve andenters the ventricle during atrialcontraction.• When the ventricles contract the leftAV valve closes and the blood ispushed into the aortic SL valve – intosystemic circulation.
  16. 16. Blood Flow Of The Heart• The heart mustperform a greatamount of work bypumping through thepulmonary andsystemic systems.•It requires a constantsupply of oxygen andnutrients via thecoronary circulation toperform this task.
  17. 17. Blood Flow Of The Heart• Blood flows into the heart via the right andleft coronary arteries. The location of theopenings to these arteries are behind theaortic valve. The openings are called ostia• When the aortic valve closes afterventricular systole, blood can flow in aretrograde manner into the coronaryarteries.• In both coronary thrombosis and coronaryembolism, a blood clot blocks a certainregion of artery and blood cannot supplythat region of myocardial tissue with oxygenand nutrients. The cells will become injuredand die resulting in a myocardial infarction(MI).• Angina Pectoris is used to describe the chestpain resulting from a lack of oxygen to themyocardium.
  18. 18. ReviewAnatomy and Physiology04/17/20131. How many separate pumps does the heart act as?2. Where does the right side of the heart pump blood into?3. Where does the left side of the heart pump blood into?4. What are the names of the two large veins which empty deoxygenatedblood from the superior and inferior portions of the body into the rightatrium?5. Explain why oxygenated blood is not found in the pulmonary arteries butit is found in the pulmonary veins.6. What is the name of the circulation that provides oxygen and nutrients tomyocardial tissue?7. Where are the openings of the right and left coronary arteries found?8. What are these openings called?9. How and when does blood flow into the right and left coronary artery?
  19. 19. Cardiac Cycle• The normal beating of the heart isregular and in a specific rhythm.• Each complete heartbeat is called acardiac cycle and includes systoleand diastole (contraction andrelaxation).• Each cycle takes about 0.8 secondsto complete if the heart is beating ata rate of 72 beats per minute.• Stoke Volume (SV) = the volume ofblood ejected from the ventriclesduring each beat.• Cardiac Output (CO) = the volumeof blood pumped by one ventricleper minute. CO = HR x SV• Normal CO = 5 L/min
  20. 20. Some Normal Values• Stroke Volume (SV) = 60 – 130 ml• Heart rate (HR) = 60 – 100 bpm• Cardiac Output (CO) = 4 – 8 L/min• Systolic Pressure = 100 – 140 mmHg• Diastolic Pressure = 60 – 90 mmHg• Ejection Fraction (EF) = 50 – 70%* ( percentage of blood ejected from LV) *
  21. 21. Conduction System of theHeart• Cardiac muscle cells have an intrinsicproperty of contracting on theirown.• The rate of contraction is controlledby the autonomic nervous system.• The heart has its own conductionsystem for coordinating contractionsduring the cardiac cycle.• Intercalated disks are connectionsthat electrically join cardiac musclefibers into a single unit that allowsfor impulse conduction through theentire wall of a heart chamber.
  22. 22. Conduction System of theHeart• The structures that make of theconduction system of the heart are:• Sinoartrial node or pacemaker.• Atrioventricular Node (AV node)• AV bundle, or bundle of His• Purkinje fibers• Impulse conduction starts in the SAnode.• It spreads in all directions throughthe atria. This causes atrial fibers tocontract.• The pulse will then travel to the AVnode and to the AV bundle / bundleof His and to the Purkinje fibers tocause ventricular contraction.
  23. 23. Conduction System of theHeart• Normally, therefore a ventricularbeat will follow an atrial beat.• Myocardial infarctions, endocarditisand other heart disorders can causethe heart’s conduction system tomalfunction.• Heart block occurs when impulsescannot reach the ventricles. Theventricles will therefore contract at amuch slower rate than normal.• This condition may be treated by theimplantation of an artificialpacemaker that will increase the rateof ventricular contractions tonormal.
  24. 24. Conduction System of theHeart• Small electrical currents aregenerated by the conduction systemof the heart.• These currents can travel throughsurrounding tissues to the surface ofthe body and be transformed intovisible tracings by anelectrocardiogram – EKG or ECG• The EKG is a graphical record of theheart’s activity.
  25. 25. Electrocardiogram Waves• The P wave –atrialdepolarization (contraction)•QRS complex – Ventriculardepolarization and atrialrepolarization (relaxation)•T wave – Ventricularrepolarization
  26. 26. Anatomy and PhysiologyReview 04/25/20131. What is the term for each complete heartbeat?2. How long does it take for a cardiac cycle to complete if the heart rate is72 beats per minute?3. Define stroke volume and cardiac output.4. What is the formula for finding cardiac output?5. The rate of cardiac muscle tissue is controlled by what system within thebody?6. What are the functions of intercalated disks?7. List the structures that make up the conduction system of the heart.8. Outline the path of electrical impulses through the heart including whatchambers are involved.9. Name two cardiac abnormalities that can cause the conduction system tomalfunction.10. What is heartblock and how can it be treated?11. What is an EKG and describe three common waves or deflections.
  27. 27. Electrocardiogram• P wave – Atrialdepolarization, spreads fromthe RA to the LA.Normal value = 80ms• PR Segment – Impulse doesnot produce contraction, it istraveling toward ventricles.Normal = 50 to 120 ms.• PR Interval – The time ittakes for the impulse to travelfrom the SA node to the AVnode where it then enters theventricles. The normal value is120-200 ms.
  28. 28. Electrocardiogram• QRS Complex – Rapiddepolarization of right and leftventricles. Normal Ranges = 80 to120 ms.•Shorter QRS values are found inchildren and in rapid states ofheart beat – tachycardia.•Prolonged values = hyperkalemiaor bundle branch block.•J Point – Point at which QRS endsand ST segments begins.•ST segment = ventricles aredepolarized. Normal = 80 to 120ms above = MI•T wave = 160 ms ventricles relax.•U = IV septum repolarization
  29. 29. Electrocardiogram• ST interval – Measuredfrom J point to end of Twave. Normal = 320 ms.•Represents slow phase ofventricular repolarization.•QT interval – Measuredfrom beginning of QRS toend of T. Normal = up to420 ms in heart rates of 60bpm.•Prolonged QT = vetriculartachyarthmias and suddendeath.
  30. 30. Blood Vessels• Arterial blood is pumpedthrough a series of largedistribution vessels-arteries.• The largest artery in thebody is the aorta.•Arteries progressivelybecome smaller as theymove away from the heartbecoming arterioles.• Arterioles control theflow of blood intomicroscopic exchangevessels called capillaries.
  31. 31. Blood Vessels• Blood enters viacapillary sphincter smoothmuscle cells. Within thecapillary beds, theexchange of nutrients andgases occur between bloodand the tissue fluid aroundthe cells.• The blood is drained fromthe capillary bed and thenenters vessels calledvenules whichprogressively becomelarger to form veins.• The two largest veins theSVC and the IVC returnblood to the RA.
  32. 32. Structure of Vessels• Arteries, veins and capillariesdiffer in structure.•Three layers are found in arteriesand veins.•The outermost layer = tunicaexterna or adventitia. It is made ofconnective tissue fibers toreinforce the walls under pressure.• The tunica media is the smoothmuscle middle layer. It is muchthicker in arteries than in veinsand contains a thin layer of elastictissue. This layer is under controlof the ANS and maintains BP andblood distribution.
  33. 33. Structure of Vessels• The tunica intima linesthe arteries and veins. It isa single layer of squamousepithelial cells calledendothelium that lines theinner surface of the entirecardiovascular system.• The veins have one-wayvalves not present inarteries. These valvesprevent backflow of blood.
  34. 34. Anatomy and PhysiologyReview 04/26/20131. Describe the P wave, the PR segment and the PR interval.2. Where would you expect to find shorter QRS values?3. What conditions would reflect prolonged QRS values?4. ST segment elevated values are an indication of what type of cardiacevent?5. What do U wave deflections indicate?6. What could be the cause of a prolonged QT interval?7. What is the name of the largest artery in the body?8. As arteries become smaller, what type of vessels do they become?9. When blood leaves the capillary bed, what vessel does it travel through?10. Name and describe the three structural layers of arteries and veins.11. What structure is found in veins but not found in arteries?
  35. 35. Hepatic PortalCirculation• Hepatic portal circulation refers tothe route of blood flow through theliver.• Veins from the stomach, intestines,gallbladder and spleen do not pourblood directly into the Inferior VenaCava (IVC) as do the veins from otherabdominal organs.• Blood is funneled to the liver by thehepatic portal vein.• Blood passes through the liverbefore it reenters regular venousreturn to the heart.• Blood exits the liver via hepatic veinswhich drain into the IVC.
  36. 36. Hepatic Portal Circulation• The diverted blood in this circulatorypath is sent through a secondcapillary bed in the liver.• Liver cells can remove highconcentrations of glucose andconvert it to glycogen.• Liver cells can also remove anddetoxify various poisonoussubstances that may be in the blood.• This system is another example ofhelping the body maintainhomeostasis.
  37. 37. Fetal Circulation• Circulation in the body before birthdiffers from circulation after birthbecause the fetus must obtainoxygen and nutrients only frommaternal blood.• Fetal blood must be carried to theplacenta and returned to the body ofthe fetus.• This is accomplished by three vesselsthat compose the umbilical cord.• Two umbilical arteries• One umbilical vein• The umbilical artery carries oxygenpoor blood.• The umbilical vein carries oxygenrich blood.
  38. 38. Fetal Circulation• The ductus venosus is a continuationof the umbilical vein.• It serves as a shunt allowing theblood to bypass the immature liverand empty directly into the IVC.• The foramen ovale shunts bloodfrom the RA to the LA, bypassing theimmature lungs.• The ductus arteriosus connects theaorta and the pulmonary artery. Theblood will bypass the lungs throughthis route.
  39. 39. Anatomy and Physiology Review04/30/20131. What does hepatic portal circulation refer to?2. Veins from which organs do not pour directly into the IVC?3. What vein funnels blood into the liver?4. What are two functions that this system can provide forblood traveling through its capillary bed?5. Name the three vessels that carry blood to the placenta andreturn it to fetus.6. What is the function of the foramen ovale?
  40. 40. Bell Ringer 04/30/2013Label and Describe each wave of the EKG trace below
  41. 41. Blood Pressure• The pressure or push of blood asit flows through thecardiovascular system.• It is the highest in the arteriesand the lowest in the veins.• The blood pressure gradient isthe difference between twoblood pressures.• The BP for systemic circulation isthe difference of the mean BP inthe aorta and the pressure at thetermination of the vena cava.
  42. 42. Blood Pressure• The mean BP in the aorta is100 mmHg and within thetermination of the venacava it is 0 mmHg.• The systemic BP gradient is100 - 0 = 100 mmHg.• The BP gradient isresponsible for keeping theblood flowing.• When a BP gradient is notpresent, blood does notcirculate.
  43. 43. Blood Pressure• Hypertension HTN – highblood pressure can causethe rupture of one or moreblood vessels.• If BP is too low -hypotension, then vitalorgans will not be perfused.Circulation would sooncease.• Massive hemorrhage cankill in this way.
  44. 44. Factors that Influence Blood Pressure• Blood Volume• Strength of Contraction• Heart Rate• Thickness of BloodBlood Volume – The largerthe volume of blood in thearteries, the greater thepressure that is exerted ontheir walls.• The lower the volume, thelower the blood pressure.
  45. 45. Factors that Influence Blood Pressure• Hemorrhage is apronounced loss of blood,this decrease in volumecauses a decrease in BP.• Diuretics-drugs thatpromote water loss byincreasing urine output.• These drugs are often usedto treat HTN by decreasingblood volume.
  46. 46. Factors that InfluenceBlood Pressure• The volume of blood in the arteriesis determined by how much blood ispumped into them by the heart.• It is also determined by how muchblood is being drained from them viathe arterioles.• The diameter of the arterioles playsan important role in determininghow much blood is drained from thearteries.• Heart Contractions – Strength andrate of the heartbeat affect CO andtherefore BP.• The stronger the contraction, themore blood is pumped into thearteries.
  47. 47. Anatomy and PhysiologyReview 05/01/20131. What can blood pressure be defined as?2. Where is blood pressure normally the highest and the lowest?3. What is a blood pressure gradient?4. How is the systemic blood pressure gradient determined?5. What is the blood pressure gradient responsible for?6. What is the difference between hypertension and hypotension?7. What affects can hypertension and hypotension have on the circulatorysystem?8. Name three factors that can influence blood pressure.9. How does the volume of blood in the arteries increase or decrease bloodpressure?10. What type of drugs are commonly used to treat hypertension and howdo they work?
  48. 48. Factors that influenceBlood Pressure• A decrease in the heart’s output willdecrease the volume of blood in thearteries. The decrease in arterialblood volume decreases bloodpressure.• A stronger heartbeat increases bloodpressure, and a weaker beatdecreases it.• Heart Rate - The rate of theheartbeat also may affect arterialblood pressure.• When the heart beats faster, moreblood enters the aorta, andtherefore the arterial blood pressureshould increase if the SV does notdecrease.
  49. 49. Factors that influenceBlood Pressure• When a change in heart rateproduces a change in blood pressurethere must also be a change instroke volume.• Blood viscosity - If blood becomesless viscous than normal, bloodpressure will decrease.• If a person suffers a hemorrhage,fluid moves into the blood from theinterstitial fluid. This dilutes theblood and decreases blood pressure.• Polycythemia is a condition in whichthe number of red blood cellsincrease to compensate for lowoxygen levels. This can cause anincrease in viscosity.
  50. 50. Factors That InfluenceBlood Pressure• Peripheral Resistance describes anyforce that acts against the flow ofblood in a blood vessel.• Tension of muscles within the wallsof blood vessels can affect PR.• When blood vessel walls are relaxedresistance is low.• When blood vessel muscles arecontracted resistance is high.• Vasomotor mechanism- adjustmentof muscle tension in vessel walls tocontrol blood pressure and bloodflow.• CVP – Central Venous Pressureshould be 0 mmHg. If not, bloodflow into RA is slowed.
  51. 51. Anatomy and Physiology Review05/06/20131. What affect does a strong heartbeat have on blood pressure?2. How does stroke volume affect heart rate and blood pressure?3. What is the relationship between blood viscosity and blood pressure?4. What is polycythemia?5. What can peripheral resistance be defined as?6. When blood vessel walls are contracted, what happens to PR?7. What is a vasomotor mechanism?8. What is normal CVP?9. If the CVP is above normal, what could the problem possibly be?
  52. 52. Factors of CVPMechanisms that keepVenous Blood Moving IntoThe Cardiovascular Circuit1.Continuous beating of theheart which pumps bloodthrough the CV system2. Adequate pressure in thearteries to push blood toAnd through the veins3. Semilunar valves in the veinsthat ensure continued bloodflow in one direction4. Contraction of skeletalmuscles which squeeze veinsTo produce a pumpingaction of blood.5. Changing pressure in theChest cavity duringbreathing can produce aPumping action in theveins of the thorax.
  53. 53. Pulse Pressure• Pulse results from an arteryexpanding and thenrecoiling.• To feel a pulse , you mustplace the fingertips over anartery that lies near thesurface of the body andover a bone or other firmbase.• A pulse can provideinformation about the rate,strength and rhythm of aheartbeat.
  54. 54. Pulse Pressure• Pulse results from an arteryexpanding and thenrecoiling.• To feel a pulse , you mustplace the fingertips over anartery that lies near thesurface of the body andover a bone or other firmbase.• A pulse can provideinformation about the rate,strength and rhythm of aheartbeat.
  55. 55. Pulse Pressure• Three pulse points arelocated on each side of thehead and neck:1. superficial temporal arteryin front of the ear2. The common carotid arteryin the neck along the edgeof the sternocleidomastoidmuscle3. The facial artery at thelower margin of themandible below the mouth
  56. 56. Pulse Pressure• Pulse points are located atthree points in the upperlimb.1. Axilla over the axillaryartery2. Brachial artery at the bendof the elbow3. Radial artery at the wristMost frequentlymonitored pulse.
  57. 57. Pulse Pressure• Pulse points are locatedon three locations in thelower extremities.1. Femoral artery2. Popliteal artery – behindand proximal to the knee3. Dorsalis pedis artery – onthe front surface of thefoot just below the bendof the ankle joint.
  58. 58. Anatomy and PhysiologyReview 05/09/20131. Name three mechanisms that keep venous blood movingback through the CV circuit into the RA.2. What causes a pulse?3. To feel a pulse, what must you do?4. What information can a pulse provide?5. Name three pulse points located on each side of the headand neck.6. Name three pulse points of the upper limb.7. Name the three pulse points of the lower extremities.8. Where is the popliteal artery located?