Cardiovascular system

1. Cardiovascular SystemCardiovascular System
G2G2
MUHAMMAD DARWESHMUHAMMAD DARWESH
NUMAIR AHMEDNUMAIR AHMED
MEHRU NISAMEHRU NISA
SABA ABID,SHAZIA TARIQSABA ABID,SHAZIA TARIQ

2. The Blood VesselsThe Blood Vessels
 TheThe cardiovascular systemcardiovascular system has threehas three
types of blood vessels:types of blood vessels:
 ArteriesArteries (and(and arteriolesarterioles) – carry blood) – carry blood
away from the heartaway from the heart
 CapillariesCapillaries – where nutrient and gas– where nutrient and gas
exchange occurexchange occur
 VeinsVeins (and(and venulesvenules) – carry blood toward) – carry blood toward
the heart.the heart.

3. The ArteriesThe Arteries
 ArteriesArteries and arterioles take bloodand arterioles take blood
away from the heart.away from the heart.
 The largest artery is theThe largest artery is the aortaaorta..
 The middle layer of an artery wallThe middle layer of an artery wall
consists ofconsists of smooth musclesmooth muscle that canthat can
constrict to regulate blood flow andconstrict to regulate blood flow and
blood pressure.blood pressure.
 ArteriolesArterioles can constrict or dilate,can constrict or dilate,
changing blood pressure.changing blood pressure.

4. The VeinsThe Veins
 VenulesVenules drain blood from capillaries,drain blood from capillaries,
then join to formthen join to form veinsveins that take bloodthat take blood
to the heart.to the heart.
 Veins have much less smooth muscleVeins have much less smooth muscle
and connective tissue than arteries.and connective tissue than arteries.
 Veins often haveVeins often have valvesvalves that preventthat prevent
the backward flow of blood whenthe backward flow of blood when
closed.closed.
 Veins carry about 70% of the body’sVeins carry about 70% of the body’s
blood and act as ablood and act as a reservoirreservoir duringduring
hemorrhagehemorrhage..

5. The CapillariesThe Capillaries
 CapillariesCapillaries have walls only one cell thick tohave walls only one cell thick to
allow exchange of gases and nutrientsallow exchange of gases and nutrients
with tissue fluid.with tissue fluid.
 Capillary beds are present in all regions ofCapillary beds are present in all regions of
the body but not all capillary beds arethe body but not all capillary beds are
open at the same time.open at the same time.
 Contraction of aContraction of a sphinctersphincter musclemuscle closescloses
off a bed and blood can flow through anoff a bed and blood can flow through an
arteriovenous shuntarteriovenous shunt that bypasses thethat bypasses the
capillary bed.capillary bed.

6. Blood vesselsBlood vessels

7. Anatomy of a capillary bedAnatomy of a capillary bed

8.  TheThe heartheart is a cone-shaped, muscularis a cone-shaped, muscular
organ located between the lungsorgan located between the lungs
behind the sternum.behind the sternum.
 The heart muscle forms theThe heart muscle forms the
myocardiummyocardium, with tightly interconnect, with tightly interconnect
cells ofcells of cardiac musclecardiac muscle tissue.tissue.
 TheThe pericardiumpericardium is the outeris the outer
membranous sac with lubricating fluid.membranous sac with lubricating fluid.
The HeartThe Heart

9.  The heart has four chambers: two upper,The heart has four chambers: two upper,
thin-walledthin-walled atriaatria, and two lower, thick-, and two lower, thick-
walledwalled ventriclesventricles..
 TheThe septumseptum is a wall dividing the rightis a wall dividing the right
and left sides.and left sides.
 Atrioventricular valvesAtrioventricular valves occur between theoccur between the
atria and ventricles – theatria and ventricles – the tricuspidtricuspid valvevalve
on the right and theon the right and the bicuspid valvebicuspid valve on theon the
left; both valves are reenforced byleft; both valves are reenforced by
chordae tendinaechordae tendinae attached to muscularattached to muscular
projections within the ventricles.projections within the ventricles.

10. External heart anatomyExternal heart anatomy

11. Coronary artery circulationCoronary artery circulation

12. Passage of Blood ThroughPassage of Blood Through
the Heartthe Heart
 Blood follows this sequence through theBlood follows this sequence through the
heart: superior and inferior vena cavaheart: superior and inferior vena cava →→
right atriumright atrium → tricuspid valve →→ tricuspid valve → rightright
ventricleventricle → pulmonary semilunar valve →→ pulmonary semilunar valve →
pulmonary trunk and arteries to the lungspulmonary trunk and arteries to the lungs →→
pulmonary veins leaving the lungspulmonary veins leaving the lungs →→ leftleft
atriumatrium → bicuspid valve →→ bicuspid valve → left ventricleleft ventricle →→
aortic semilunar valve →aortic semilunar valve → aortaaorta → to the→ to the
bodybody..

13. Internal view of the heartInternal view of the heart

14.  The pumping of the heart sends out bloodThe pumping of the heart sends out blood
under pressure to the arteries.under pressure to the arteries.
 Blood pressureBlood pressure is greatest in the aorta; theis greatest in the aorta; the
wall of the left ventricle is thicker than thatwall of the left ventricle is thicker than that
of the right ventricle and pumps blood toof the right ventricle and pumps blood to
the entire body.the entire body.
 Blood pressure then decreases as theBlood pressure then decreases as the
cross-sectional area of arteries and thencross-sectional area of arteries and then
arterioles increases.arterioles increases.

15. Path of blood through thePath of blood through the
heartheart

16. The HeartbeatThe Heartbeat
 Each heartbeat is called aEach heartbeat is called a cardiac cyclecardiac cycle..
 When the heart beats, the two atriaWhen the heart beats, the two atria
contract together, then the two ventriclescontract together, then the two ventricles
contract; then the whole heart relaxes.contract; then the whole heart relaxes.
 SystoleSystole is the contraction of heartis the contraction of heart
chambers;chambers; diastolediastole is their relaxation.is their relaxation.
 TheThe heart soundsheart sounds, lub-dup, are due to, lub-dup, are due to
the closing of the atrioventricular valves,the closing of the atrioventricular valves,
followed by the closing of the semilunarfollowed by the closing of the semilunar
valves.valves.

17. Intrinsic Control of HeartbeatIntrinsic Control of Heartbeat
 TheThe SASA ((sinoatrialsinoatrial)) nodenode, or, or pacemakerpacemaker,,
initiates the heartbeat and causes the atriainitiates the heartbeat and causes the atria
to contract on average every 0.85to contract on average every 0.85
seconds.seconds.
 TheThe AVAV ((atrioventricularatrioventricular)) nodenode conveysconveys
the stimulus and initiates contraction of thethe stimulus and initiates contraction of the
ventricles.ventricles.
 The signal for the ventricles to contractThe signal for the ventricles to contract
travels from the AV node through thetravels from the AV node through the
atrioventricular bundleatrioventricular bundle to the smallerto the smaller
Purkinje fibersPurkinje fibers..

18. Conduction system of theConduction system of the
heartheart

19. Extrinsic Control of HeartbeatExtrinsic Control of Heartbeat
 AA cardiac control centercardiac control center in the medullain the medulla
oblongata speeds up or slows down theoblongata speeds up or slows down the
heart rate by way of the autonomicheart rate by way of the autonomic
nervous system branches:nervous system branches:
parasympathetic systemparasympathetic system (slows heart(slows heart
rate) and therate) and the sympathetic systemsympathetic system
(increases heart rate).(increases heart rate).
 HormonesHormones epinephrineepinephrine andand
norepinephrinenorepinephrine from the adrenalfrom the adrenal
medulla also stimulate faster heart rate.medulla also stimulate faster heart rate.

20. The ElectrocardiogramThe Electrocardiogram
 AnAn electrocardiogramelectrocardiogram ((ECGECG) is a) is a
recording of the electrical changesrecording of the electrical changes
that occur in the myocardium during athat occur in the myocardium during a
cardiac cycle.cardiac cycle.
 Atrial depolarizationAtrial depolarization creates thecreates the PP
wavewave,, ventricle depolarizationventricle depolarization createscreates
thethe QRS waveQRS wave, and, and repolarizationrepolarization ofof
the ventricles produces thethe ventricles produces the T waveT wave..

21. ElectrocardiogramElectrocardiogram

22. The Vascular PathwaysThe Vascular Pathways
 The cardiovascular system includesThe cardiovascular system includes
two circuits:two circuits:
1)1) Pulmonary circuitPulmonary circuit which circulateswhich circulates
blood through the lungs, andblood through the lungs, and
2)2) Systemic circuitSystemic circuit which circulateswhich circulates
blood to the rest of the body.blood to the rest of the body.
3)3) Both circuits are vital toBoth circuits are vital to
homeostasis.homeostasis.

23. Cardiovascular systemCardiovascular system
diagramdiagram

24. The Pulmonary CircuitThe Pulmonary Circuit
 TheThe pulmonary circuitpulmonary circuit begins with thebegins with the
pulmonary trunkpulmonary trunk from the right ventriclefrom the right ventricle
which branches into twowhich branches into two pulmonarypulmonary
arteriesarteries that take oxygen-poor blood tothat take oxygen-poor blood to
the lungs.the lungs.
 In the lungs, oxygen diffuses into theIn the lungs, oxygen diffuses into the
blood, and carbon dioxide diffuses outblood, and carbon dioxide diffuses out
of the blood to be expelled by the lungs.of the blood to be expelled by the lungs.
 FourFour pulmonary veinspulmonary veins return oxygen-return oxygen-
rich blood to the left atrium.rich blood to the left atrium.

25. The Systemic CircuitThe Systemic Circuit
 TheThe systemic circuitsystemic circuit starts with the aortastarts with the aorta
carrying Ocarrying O22-rich blood from the left-rich blood from the left
ventricle.ventricle.
 The aorta branches with an artery goingThe aorta branches with an artery going
to each specific organ.to each specific organ.
 Generally, an artery divides intoGenerally, an artery divides into
arterioles and capillaries which thenarterioles and capillaries which then
lead to venules.lead to venules.

26.  The vein that takes blood to the vena cavaThe vein that takes blood to the vena cava
often has the same name as the arteryoften has the same name as the artery
that delivered blood to the organ.that delivered blood to the organ.
 In the adult systemic circuit, arteries carryIn the adult systemic circuit, arteries carry
blood that is relatively high in oxygen andblood that is relatively high in oxygen and
relatively low in carbon dioxide, and veinsrelatively low in carbon dioxide, and veins
carry blood that is relatively low in oxygencarry blood that is relatively low in oxygen
and relatively high in carbon dioxide.and relatively high in carbon dioxide.
 This is the reverse of the pulmonaryThis is the reverse of the pulmonary
circuit.circuit.

27. Major arteries and veins ofMajor arteries and veins of
the systemic circuitthe systemic circuit

28.  TheThe coronary arteriescoronary arteries serve the heartserve the heart
muscle itself; they are the first branch offmuscle itself; they are the first branch off
the aorta.the aorta.
 Since the coronary arteries are so small,Since the coronary arteries are so small,
they are easily clogged, leading to heartthey are easily clogged, leading to heart
disease.disease.
 TheThe hepatic portal systemhepatic portal system carries bloodcarries blood
rich in nutrients from digestion in therich in nutrients from digestion in the
small intestine to the liver, the organ thatsmall intestine to the liver, the organ that
monitors the composition of the bloodmonitors the composition of the blood..

29. Cardiovascular DisordersCardiovascular Disorders
 Cardiovascular diseaseCardiovascular disease ((CVDCVD) is the) is the
leading cause of death in Westernleading cause of death in Western
countries.countries.
 Modern research efforts have improvedModern research efforts have improved
diagnosis, treatment, and prevention.diagnosis, treatment, and prevention.
 Major cardiovascular disorders includeMajor cardiovascular disorders include
atherosclerosis, stroke, heart attack,atherosclerosis, stroke, heart attack,
aneurysm, and hypertension.aneurysm, and hypertension.

30. AtherosclerosisAtherosclerosis
 AtherosclerosisAtherosclerosis is due to a build-up ofis due to a build-up of
fatty material (fatty material (plaqueplaque), mainly), mainly
cholesterol, under the inner lining ofcholesterol, under the inner lining of
arteries.arteries.
 The plaque can cause aThe plaque can cause a thrombusthrombus (blood(blood
clot) to form.clot) to form.
 The thrombus can dislodge as anThe thrombus can dislodge as an
embolusembolus and lead toand lead to thromboembolismthromboembolism..

31. Stroke, Heart Attack, andStroke, Heart Attack, and
AneurysmAneurysm
 AA cerebrovascular accidentcerebrovascular accident, or, or strokestroke,,
results when an embolus lodges in aresults when an embolus lodges in a
cerebral blood vessel or a cerebral bloodcerebral blood vessel or a cerebral blood
vessel bursts; a portion of the brain diesvessel bursts; a portion of the brain dies
due to lack of oxygen.due to lack of oxygen.
 AA myocardial infarctionmyocardial infarction, or, or heart attackheart attack,,
occurs when a portion of heart muscleoccurs when a portion of heart muscle
dies due to lack of oxygen.dies due to lack of oxygen.

32.  Partial blockage of a coronary arteryPartial blockage of a coronary artery
causescauses angina pectorisangina pectoris, or chest pain., or chest pain.
 AnAn aneurysmaneurysm is a ballooning of a bloodis a ballooning of a blood
vessel, usually in the abdominal aorta orvessel, usually in the abdominal aorta or
arteries leading to the brain.arteries leading to the brain.
 Death results if the aneurysm is in a largeDeath results if the aneurysm is in a large
vessel and the vessel bursts.vessel and the vessel bursts.
 Atherosclerosis and hypertension weakenAtherosclerosis and hypertension weaken
blood vessels over time, increasing theblood vessels over time, increasing the
risk of aneurysm.risk of aneurysm.

33. Coronary BypassCoronary Bypass
OperationsOperations
 AA coronary bypass operationcoronary bypass operation involvesinvolves
removing a segment of another bloodremoving a segment of another blood
vessel and replacing a cloggedvessel and replacing a clogged
coronary artery.coronary artery.
 It may be possible to replace thisIt may be possible to replace this
surgery withsurgery with gene therapygene therapy thatthat
stimulates new blood vessels to growstimulates new blood vessels to grow
where the heart needs more blood flow.where the heart needs more blood flow.

34. Coronary bypass operationCoronary bypass operation

35. Clearing Clogged ArteriesClearing Clogged Arteries
 AngioplastyAngioplasty uses a long tube threadeduses a long tube threaded
through an arm or leg vessel to thethrough an arm or leg vessel to the
point where the coronary artery ispoint where the coronary artery is
blocked; inflating the tube forces theblocked; inflating the tube forces the
vessel open.vessel open.
 Small metalSmall metal stentsstents are expanded insideare expanded inside
the artery to keep it open.the artery to keep it open.
 Stents are coated withStents are coated with heparinheparin toto
prevent blood clotting and withprevent blood clotting and with
chemicals to prevent arterial closing.chemicals to prevent arterial closing.

36. AngioplastyAngioplasty

37. Dissolving Blood ClotsDissolving Blood Clots
 Medical treatments for dissolving bloodMedical treatments for dissolving blood
clots include use ofclots include use of t-PAt-PA ((tissuetissue
plasminogen activatorplasminogen activator) that converts) that converts
plasminogen into plasmin, an enzyme thatplasminogen into plasmin, an enzyme that
dissolves blood clots, but can cause braindissolves blood clots, but can cause brain
bleeding.bleeding.
 AspirinAspirin reduces the stickiness of plateletsreduces the stickiness of platelets
and reduces clot formation and lowers theand reduces clot formation and lowers the
risk of heart attack.risk of heart attack.

38. Heart Transplants andHeart Transplants and
Artificial HeartsArtificial Hearts
 Heart transplantsHeart transplants are routinelyare routinely
performed but immunosuppressive drugsperformed but immunosuppressive drugs
must be taken thereafter.must be taken thereafter.
 There is a shortage of human organThere is a shortage of human organ
donors.donors.
 Work is currently underway to improveWork is currently underway to improve
self-containedself-contained artificial heartsartificial hearts, and, and
muscle cell transplants may someday bemuscle cell transplants may someday be
usefuluseful..

39. HypertensionHypertension
 About 20% of Americans suffer fromAbout 20% of Americans suffer from
hypertensionhypertension ((high blood pressurehigh blood pressure).).
 Hypertension is present when systolicHypertension is present when systolic
pressure is 140 or greater or diastolicpressure is 140 or greater or diastolic
pressure is 100 or greater; diastolic pressurepressure is 100 or greater; diastolic pressure
is emphasized when medical treatment isis emphasized when medical treatment is
considered.considered.
 A genetic predisposition for hypertensionA genetic predisposition for hypertension
occurs in those who have a gene that codesoccurs in those who have a gene that codes
forfor angiotensinogenangiotensinogen, a powerful, a powerful
vasoconstrictor.vasoconstrictor.