Circulation and Cardiovascular System

2
Circulatory SystemsCirculatory Systems
OutlineOutline
Transport in InvertebratesTransport in Invertebrates
Open versus Closed Circulatory SystemsOpen versus Closed Circulatory Systems
Transport in VertebratesTransport in Vertebrates
Transport in HumansTransport in Humans
HeartbeatHeartbeat
Vascular PathwaysVascular Pathways
Blood PressureBlood Pressure
Cardiovascular DisordersCardiovascular Disorders
BloodBlood
ComponentsComponents
ClottingClotting

3
Small aquatic animals with no circulatorySmall aquatic animals with no circulatory
systemsystem
May rely on external water inMay rely on external water in
gastrovascular cavity to service cellsgastrovascular cavity to service cells
Roundworms and otherRoundworms and other
pseudocoelomatespseudocoelomates
Use a fluid-filled body cavity as a meansUse a fluid-filled body cavity as a means
of transporting substancesof transporting substances
Fluid-filled cavity can also act as aFluid-filled cavity can also act as a
hydrostatic skeletonhydrostatic skeleton
Animals that have a rigid skeletonAnimals that have a rigid skeleton
May still rely on body fluids for theMay still rely on body fluids for the
purpose of locomotionpurpose of locomotion
Bivalves pump hemolymph into the footBivalves pump hemolymph into the foot

4Aquatic Organisms
Without a Circulatory
System

5
Open vs. ClosedOpen vs. Closed
Invertebrate CirculationInvertebrate Circulation
Two types of circulatory fluids:Two types of circulatory fluids:
 Blood - contained within blood vesselsBlood - contained within blood vessels
 Hemolymph - flows into hemocoelHemolymph - flows into hemocoel
Open Circulatory SystemOpen Circulatory System
 Heart pumps hemolymph via vesselsHeart pumps hemolymph via vessels
 Vessels empty into tissue spacesVessels empty into tissue spaces
Closed Circulatory SystemClosed Circulatory System
 Heart pumps blood to capillariesHeart pumps blood to capillaries
 Gases and materials diffuse to and from nearbyGases and materials diffuse to and from nearby
cellscells
 Vessels return blood to heart without itVessels return blood to heart without it

6Open vs. Closed Circulatory
Systems

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Transport in the VertebratesTransport in the Vertebrates
All vertebrates have a closed cardiovascularAll vertebrates have a closed cardiovascular
systemsystem
Vertebrate heart:Vertebrate heart:
 Atrial chamber(s) of heart receive blood fromAtrial chamber(s) of heart receive blood from
general circulationgeneral circulation
 Ventricle chamber(s) of heart pump blood outVentricle chamber(s) of heart pump blood out
through blood vesselsthrough blood vessels
Vertebrate vessels:Vertebrate vessels:
 Arteries - Carry blood away from heartArteries - Carry blood away from heart
 Arterioles – Lead to capillariesArterioles – Lead to capillaries
 Capillaries - Exchange materials with tissueCapillaries - Exchange materials with tissue
fluidfluid
 Venules - Lead to veinsVenules - Lead to veins

8Transport in Birds and
Mammals

9Comparison of Circulatory
Circuits
in Vertebrates

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Comparison of Circulatory PathwaysComparison of Circulatory Pathways
Fish - Blood flows in single loopFish - Blood flows in single loop
Single atrium and single ventricleSingle atrium and single ventricle
Amphibians - Blood flows in double loopAmphibians - Blood flows in double loop
Two atria with single ventricleTwo atria with single ventricle
Other vertebrates - Blood flows in aOther vertebrates - Blood flows in a
double loopdouble loop
Heart divided by septum into separateHeart divided by septum into separate
sidessides

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Human HeartHuman Heart
Fist-sizedFist-sized
Cone-shapedCone-shaped
Very muscular organ (special cardiacVery muscular organ (special cardiac
fibers)fibers)
Lies within a fluid-filled sac (theLies within a fluid-filled sac (the
pericardium)pericardium)

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Human Heart:Human Heart:
Gross AnatomyGross Anatomy
Septum separates heart into left & rightSeptum separates heart into left & right
halveshalves
Each half has two chambersEach half has two chambers
Upper two chambers are the atriaUpper two chambers are the atria
Thin-walledThin-walled
Receive blood from circulationReceive blood from circulation
Lower two chambers are the ventriclesLower two chambers are the ventricles
Thick-walledThick-walled
Pump blood away from heartPump blood away from heart

15
Human Heart:Human Heart:
ValvesValves
Valves open and close to control bloodValves open and close to control blood
flow through heartflow through heart
Atrioventricular valvesAtrioventricular valves
TricuspidTricuspid
BicuspidBicuspid
Semilunar valvesSemilunar valves
PulmonaryPulmonary
AorticAortic

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Blood returning to heart from systemic circuitBlood returning to heart from systemic circuit
 Enters right atriumEnters right atrium
 Right atrium pumps through tricuspid valve toRight atrium pumps through tricuspid valve to
right ventricleright ventricle
 Right ventricle pumps blood through pulmonaryRight ventricle pumps blood through pulmonary
valve to the pulmonary circuitvalve to the pulmonary circuit
Blood returning to heart from pulmonary circuitBlood returning to heart from pulmonary circuit
 Enters left atriumEnters left atrium
 Left atrium pumps through mitral valve to leftLeft atrium pumps through mitral valve to left
ventricleventricle
 Left ventricle pumps blood through aortic valveLeft ventricle pumps blood through aortic valve
to the systemic circuitto the systemic circuit
Oxygen-poor blood never mixes with oxygen-Oxygen-poor blood never mixes with oxygen-
rich blood (in humans)rich blood (in humans)

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HeartbeatHeartbeat
Systole - Contraction of heart chambersSystole - Contraction of heart chambers
Diastole - Relaxation of heart chambersDiastole - Relaxation of heart chambers
Pulse - Two-part pumping action that takesPulse - Two-part pumping action that takes
about a secondabout a second
 Blood collects in atria, the atria contractBlood collects in atria, the atria contract
Pushes blood through tricuspid and mitral valvesPushes blood through tricuspid and mitral valves
into the resting lower ventriclesinto the resting lower ventricles
This phase (the longer of the two) is called theThis phase (the longer of the two) is called the
diastolediastole
 Second part begins when ventricles fillSecond part begins when ventricles fill
Ventricles contractVentricles contract
This is called systoleThis is called systole
 After blood moves into the pulmonary artery andAfter blood moves into the pulmonary artery and
aorta, the ventricles relaxaorta, the ventricles relax

18Conduction System of the
Heart

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HeartbeatHeartbeatRhythmic contraction due to cardiacRhythmic contraction due to cardiac
conduction systemconduction system
Sinoatrial node (SA) keeps the heartbeatSinoatrial node (SA) keeps the heartbeat
regularregular
Atrioventricular node (AV) signalsAtrioventricular node (AV) signals
ventricles to contract - Purkinje Fibersventricles to contract - Purkinje Fibers
Electrocardiogram (ECG)Electrocardiogram (ECG)
A recording of electrical changes thatA recording of electrical changes that
occurring in myocardium during cardiacoccurring in myocardium during cardiac
cyclecycle
When SA node triggers an impulse, theWhen SA node triggers an impulse, the

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Vascular PathwaysVascular Pathways
Human cardiovascular system includesHuman cardiovascular system includes
two major circular pathways:two major circular pathways:
Pulmonary CircuitPulmonary Circuit
Takes oxygen-poor blood to the lungs andTakes oxygen-poor blood to the lungs and
returns oxygen-rich blood to the heartreturns oxygen-rich blood to the heart
Systemic CircuitSystemic Circuit
Takes blood throughout the body from theTakes blood throughout the body from the
aorta to the vena cavaaorta to the vena cava

23Cross Section of a Valve in
a Vein

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Blood PressureBlood Pressure
The beat of the heart supplies pressureThe beat of the heart supplies pressure
that keeps blood moving in the arteriesthat keeps blood moving in the arteries
Systolic Pressure results from bloodSystolic Pressure results from blood
forced into the arteries during ventricularforced into the arteries during ventricular
systolesystole
Diastolic Pressure is the pressure in theDiastolic Pressure is the pressure in the
arteries during during ventricular diastolearteries during during ventricular diastole
Skeletal muscle contraction pushes bloodSkeletal muscle contraction pushes blood
in the veins toward the heartin the veins toward the heart
Blood pressureBlood pressure
Normally measured with aNormally measured with a
sphygmomanometer on the brachial arterysphygmomanometer on the brachial artery
Expressed in the form: Systolic “over”Expressed in the form: Systolic “over”

25
Hypertension - High blood pressureHypertension - High blood pressure
Atherosclerosis - Accumulation of fattyAtherosclerosis - Accumulation of fatty
materials in inner linings of arteriesmaterials in inner linings of arteries
Stroke - Cranial arteriole bursts or isStroke - Cranial arteriole bursts or is
blocked by an embolusblocked by an embolus
Heart attack – (Myocardial infarction)Heart attack – (Myocardial infarction)
Coronary artery becomes partiallyCoronary artery becomes partially
blockedblocked
Angina pectoris – Painful squeezingAngina pectoris – Painful squeezing
sensation from myocardial oxygensensation from myocardial oxygen

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Blood:Blood:
Homeostasis FunctionsHomeostasis Functions
Transports substances to and fromTransports substances to and from
capillaries for exchange with tissue fluidcapillaries for exchange with tissue fluid
Guards against pathogen invasionGuards against pathogen invasion
Regulates body temperatureRegulates body temperature
Buffers body pHBuffers body pH
Maintain osmotic pressureMaintain osmotic pressure
Clots prevent blood/fluid lossClots prevent blood/fluid loss

27
Red Blood CellsRed Blood Cells
Small, biconcave disksSmall, biconcave disks
Lack a nucleus and contain hemoglobinLack a nucleus and contain hemoglobin
Hemoglobin containsHemoglobin contains
Four globin protein chainsFour globin protein chains
Each associated with an iron-containingEach associated with an iron-containing
hemeheme
Manufactured continuously in bone marrowManufactured continuously in bone marrow
of skull, ribs, vertebrae, and ends of longof skull, ribs, vertebrae, and ends of long
bonesbones

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White Blood CellsWhite Blood Cells
Most types larger than red blood cellsMost types larger than red blood cells
Contain a nucleus and lack hemoglobinContain a nucleus and lack hemoglobin
Important in inflammatory responseImportant in inflammatory response
Neutrophils enter tissue fluid andNeutrophils enter tissue fluid and
phagocytize foreign materialphagocytize foreign material
Lymphocytes (T Cells) attack infectedLymphocytes (T Cells) attack infected
cellscells
Antigens cause body to produceAntigens cause body to produce
antibodiesantibodies

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PlateletsPlatelets
PlateletsPlatelets
Result from fragmentation ofResult from fragmentation of
megakaryocytesmegakaryocytes
Involved in coagulationInvolved in coagulation
Blood clot consists of:Blood clot consists of:
PlateletsPlatelets
Red blood cellsRed blood cells
All entangled within fibrin threadsAll entangled within fibrin threads

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Capillary ExchangeCapillary Exchange
Capillaries very narrow – Tiny RBCs mustCapillaries very narrow – Tiny RBCs must
go through single filego through single file
Wall of capillaries very thin to facilitateWall of capillaries very thin to facilitate
diffusion of nutrients, gasses and wastesdiffusion of nutrients, gasses and wastes
Oxygen and nutrients exit a capillary nearOxygen and nutrients exit a capillary near
the arterial endthe arterial end
Carbon dioxide and waste moleculesCarbon dioxide and waste molecules
enter a capillary near the venous endenter a capillary near the venous end

35
ReviewReview
Open versus Closed Circulatory SystemsOpen versus Closed Circulatory Systems
Transport in VertebratesTransport in Vertebrates
HeartbeatHeartbeat
Vascular PathwaysVascular Pathways
Blood PressureBlood Pressure
BloodBlood
ComponentsComponents
ClottingClotting

Circulatory System
Ending Slide Chapter 34

Circulation and Cardiovascular System

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