Circulatory Systems 2Outline Transport in Vertebrates Transport in Humans Heartbeat Vascular...

2Circulatory SysCirculatory Systemstems

OutlineOutline

Transport in VertebratesTransport in VertebratesTransport in Transport in HumansHumans

HeartbeatHeartbeatVascular PathwaysVascular PathwaysBlood PressureBlood Pressure

BloodBloodComponentsComponentsClottingClottingTransport in Transport in InvertebratesInvertebratesOpen versus Closed Circulatory Open versus Closed Circulatory SystemsSystems

3Circulatory SysCirculatory SystemstemsTransport in HumansTransport in Humans

Human HeartHuman Heart

Cone-shaped Cone-shaped

Size of a fist-14cm long and 9cm wideSize of a fist-14cm long and 9cm wide

Inner surface is lined with Inner surface is lined with endocardiumendocardium

Thick muscular organ (special cardiac Thick muscular organ (special cardiac fibers)-fibers)-myocardiummyocardium

Lies within the Lies within the pericardiumpericardium, a thick , a thick membranous sac that secretes a lubricating membranous sac that secretes a lubricating liquid.liquid.


Thoracic cavityThoracic cavity


Heart-lies behind the sternum and Heart-lies behind the sternum and between lungs.between lungs.


External Heart AnatomyExternal Heart Anatomy


Vascular PathwaysVascular Pathways

Human cardiovascular system includes Human cardiovascular system includes two major circular pathways:two major circular pathways:

Pulmonary CircuitPulmonary Circuit

Takes oxygen-poor blood to the lungs Takes oxygen-poor blood to the lungs and returns oxygen-rich blood to the and returns oxygen-rich blood to the heartheart

Systemic CircuitSystemic Circuit

Takes blood throughout the body from Takes blood throughout the body from the aorta to the vena cavathe aorta to the vena cava


Path of BloodPath of Blood

9Circulatory SysCirculatory SystemstemsHuman Heart:Human Heart:

Gross AnatomyGross Anatomy

Septum separates heart into left & Septum separates heart into left & right halvesright halves

The heart has four chambersThe heart has four 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

10Circulatory SysCirculatory SystemstemsHuman Heart:Human Heart:

ValvesValves

Valves open and close to control blood Valves open and close to control blood flow through heartflow through heart

Atrioventricular valves (between the Atrioventricular valves (between the atria and ventriclesatria and ventricles

TricuspidTricuspid

BicuspidBicuspid

Semilunar valves (between the Semilunar valves (between the ventricles and their attached vessels)ventricles and their attached vessels)

PulmonaryPulmonary

AorticAortic


Internal View of the HeartInternal View of the Heart

12Circulatory SysCirculatory SystemstemsCross-section of the heartCross-section of the heart


Transport in the VertebratesTransport in the VertebratesAll vertebrates have a Closed Circulatory All vertebrates have a Closed Circulatory SystemSystem

Heart pumps blood to capillariesHeart pumps blood to capillaries

Gases and materials diffuse to and from Gases and materials diffuse to and from nearby cellsnearby cells

Vessels return blood to heart without it Vessels return blood to heart without it contacting tissuescontacting tissues

Oxygen-poor blood never mixes with oxygen-Oxygen-poor blood never mixes with oxygen-rich blood (in humans)rich blood (in humans)

Vertebrate vessels:Vertebrate vessels: Arteries - Carry blood Arteries - Carry blood away away from heartfrom heart Arterioles – Lead to capillariesArterioles – Lead to capillaries Capillaries - Exchange materials with tissue Capillaries - Exchange materials with tissue fluidfluid

Venules - Lead to veinsVenules - Lead to veins Veins - Return blood to heartVeins - Return blood to heart


Transport in HumansTransport in HumansBlood returning to heart from systemic Blood returning to heart from systemic circuitcircuit Enters right atriumEnters right atrium Right atrium pumps through tricuspid valve Right atrium pumps through tricuspid valve to right ventricleto right ventricle

Right ventricle pumps blood through Right ventricle pumps blood through pulmonary valve to the pulmonary circuitpulmonary valve to the pulmonary circuit

Blood returning to heart from pulmonary Blood returning to heart from pulmonary circuitcircuit Enters left atriumEnters left atrium Left atrium pumps through mitral valve to Left atrium pumps through mitral valve to left ventricleleft ventricle

Left ventricle pumps blood through aortic Left ventricle pumps blood through aortic valve to the systemic circuitvalve to the systemic circuit


Blood Flow Through the heartBlood Flow Through the heart

16Circulatory SysCirculatory SystemstemsCardiac Cycle-70 beats/minCardiac Cycle-70 beats/min

100,000 x a day or 40 million x a year100,000 x a day or 40 million x a year

A single cardiac cycle is made up of A single cardiac cycle is made up of the events associated with one heart the events associated with one heart beat. Each cardiac cycle takes about beat. Each cardiac cycle takes about 8 tenths of one second.8 tenths of one second.

During each cardiac cycle pressure During each cardiac cycle pressure changes occur within the chambers changes occur within the chambers of the heart as they relax and of the heart as they relax and contract.contract.

As the chambers relax, they fill with As the chambers relax, they fill with blood, diastole. When the chambers blood, diastole. When the chambers contract, this is called systole.contract, this is called systole.


Cardiac cycleCardiac cycle

When the AV-opens-blood When the AV-opens-blood flows into the ventricles flows into the ventricles from the atria (semilunar from the atria (semilunar valves are closed).valves are closed).

Atrial contraction results Atrial contraction results from a series of events from a series of events beginning with the spread beginning with the spread of nerve impulses from the of nerve impulses from the SA-node across the walls SA-node across the walls of the atria. of the atria.

Ventricular filling is Ventricular filling is completed by atrial completed by atrial systole. systole.

Impulses from the AV-node Impulses from the AV-node travels along the travels along the ventricular conduction ventricular conduction fibers leading to fibers leading to contraction of the contraction of the ventricles. ventricles.


HeartbeatHeartbeat

In ventricular systole, In ventricular systole, increased pressure forces increased pressure forces the AV valves closed, the AV valves closed, “Lub” semilunar valves “Lub” semilunar valves open and blood is ejected open and blood is ejected from the ventricles. from the ventricles.

Ventricular diastole, Ventricular diastole, pressure in the ventricles pressure in the ventricles decrease and blood in the decrease and blood in the aorta and pulmonary aorta and pulmonary flows back toward the flows back toward the chambers, causing these chambers, causing these valves to close “dub”. valves to close “dub”.

Ventricular pressure falls Ventricular pressure falls below that of the atria, below that of the atria, AV valves open and cycle AV valves open and cycle begins again.begins again.


HeartbeatHeartbeat

Electrocardiogram (ECG) Fluids contain Electrocardiogram (ECG) Fluids contain ions that conduct electrical currents, ions that conduct electrical currents, electrodes placed on the skin are electrodes placed on the skin are connected to a instrument that detects connected to a instrument that detects electrical changes of the myocardium.electrical changes of the myocardium.

P- Atrial depolarization/systoleP- Atrial depolarization/systole

QRS- Ventricular depolarizationQRS- Ventricular depolarization

T-wave- Ventricular repolarizationT-wave- Ventricular repolarization


Conduction System of the HeartConduction System of the Heart


One way venous valvesOne way venous valves

During muscle contraction, venous diameter decreases, and venous pressure rises. The increase in pressure forces the flow toward the heart.


Cross Section of a Valve in a VeinCross Section of a Valve in a Vein


Blood PressureBlood PressureThe beat of the heart supplies pressure The beat of the heart supplies pressure that keeps blood moving in the arteriesthat keeps blood moving in the arteriesSystolic Pressure results from blood Systolic Pressure results from blood forced into the arteries during ventricular forced into the arteries during ventricular systolesystole

Diastolic Pressure is the pressure in the Diastolic Pressure is the pressure in the arteries during during ventricular diastolearteries during during ventricular diastole

Skeletal muscle contraction pushes blood Skeletal muscle contraction pushes blood in the veins toward the heartin the veins toward the heart

Blood pressureBlood pressureNormally measured with a Normally measured with a sphygmomanometer on the brachial arterysphygmomanometer on the brachial artery

Expressed in the form: Systolic “over” Expressed in the form: Systolic “over” DiastolicDiastolic


Transport in InvertebratesTransport in Invertebrates

Small aquatic animals with no circulatory Small aquatic animals with no circulatory systemsystemMay rely on external water in May rely on external water in gastrovascular cavity to service cellsgastrovascular cavity to service cells

Roundworms and other pseudocoelomatesRoundworms and other pseudocoelomatesUse a fluid-filled body cavity as a means of Use a fluid-filled body cavity as a means of transporting substancestransporting substances

Fluid-filled cavity can also act as a Fluid-filled cavity can also act as a hydrostatic skeleton hydrostatic skeleton

Animals that have a rigid skeletonAnimals that have a rigid skeletonMay still rely on body fluids for the May still rely on body fluids for the purpose of locomotionpurpose of locomotion

Bivalves pump hemolymph into the foot Bivalves pump hemolymph into the foot for digging into mudfor digging into mud

25Aquatic OrganismsWithout a Circulatory

System

26Circulatory SysCirculatory SystemstemsOpen 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 vesselsHemolymph - flows into hemocoelHemolymph - flows into hemocoel

Open Circulatory SystemOpen Circulatory SystemHeart pumps hemolymph via vesselsHeart pumps hemolymph via vesselsVessels empty into tissue spacesVessels empty into tissue spaces

27Open vs. Closed Circulatory Systems

28Transport in Birds and Mammals

29Comparison of Circulatory Circuits

in Vertebrates

30Circulatory SysCirculatory SystemstemsComparison of Circulatory Comparison of Circulatory

PathwaysPathwaysFish - Blood flows in single loopFish - Blood flows in single loop

Single atrium and single ventricleSingle atrium and single ventricle

Amphibians - Blood flows in double Amphibians - Blood flows in double looploop

Two atria with single ventricleTwo atria with single ventricle

Other vertebrates - Blood flows in a Other vertebrates - Blood flows in a double loopdouble loop

Heart divided by septum into separate Heart divided by septum into separate sidessides

31Circulatory SysCirculatory SystemstemsBlood:Blood:

Homeostasis FunctionsHomeostasis Functions

Transports substances to and from Transports substances to and from capillaries for exchange with tissue capillaries for exchange with tissue fluidfluid

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


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-containing Each associated with an iron-containing hemeheme

Manufactured continuously in bone Manufactured continuously in bone marrow of skull, ribs, vertebrae, and marrow of skull, ribs, vertebrae, and ends of long bonesends of long bones


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 and Neutrophils enter tissue fluid and phagocytize foreign materialphagocytize foreign material

Lymphocytes (T Cells) attack infected Lymphocytes (T Cells) attack infected cellscells

Antigens cause body to produce Antigens cause body to produce antibodiesantibodies

34Composition of Blood


PlateletsPlatelets

PlateletsPlatelets

Result from fragmentation of Result 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

36Blood Clotting


Capillary ExchangeCapillary Exchange

Capillaries very narrow – Tiny RBCs Capillaries very narrow – Tiny RBCs must go through single filemust go through single file

Wall of capillaries very thin to Wall of capillaries very thin to facilitate diffusion of nutrients, facilitate diffusion of nutrients, gasses and wastesgasses and wastes

Oxygen and nutrients exit a capillary Oxygen and nutrients exit a capillary near the arterial endnear the arterial end

Carbon dioxide and waste molecules Carbon dioxide and waste molecules enter a capillary near the venous endenter a capillary near the venous end

38Capillary Exchange

39Capillary Bed


ReviewReview

Transport in InvertebratesTransport in InvertebratesOpen versus Closed Circulatory Open versus Closed Circulatory SystemsSystems

Transport in VertebratesTransport in VertebratesTransport in HumansTransport in Humans

HeartbeatHeartbeatVascular PathwaysVascular PathwaysBlood PressureBlood Pressure

Cardiovascular DisordersCardiovascular DisordersBloodBlood

ComponentsComponentsClottingClotting

Circulatory Systems 2Outline Transport in Vertebrates Transport in Humans Heartbeat Vascular...

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