Upload
gwen-manning
View
216
Download
1
Tags:
Embed Size (px)
Citation preview
CirculationCirculationChpt. 44Chpt. 44
Transportation, cardiac cycle, Transportation, cardiac cycle, evolution of advanced systemsevolution of advanced systems
Oxygen and nutrients obtained Oxygen and nutrients obtained for simple organisms by for simple organisms by diffusion diffusion
cnidarians and flatworms – cnidarians and flatworms – bodies only 2 cells thickbodies only 2 cells thick
Development of multi-layer Development of multi-layer tissuestissues
Oxygen and nutrients Oxygen and nutrients transported in liquid via transported in liquid via circulatory systemcirculatory system
Open – mollusks, arthropods, Open – mollusks, arthropods, no distinction between circulating no distinction between circulating
fluid and fluid of body tissuesfluid and fluid of body tissues Called hemolymphCalled hemolymph
Closed – blood enclosed in Closed – blood enclosed in vessels, transport away and vessels, transport away and back to a pump (heart)back to a pump (heart)
Some invertebrates (annelids)Some invertebrates (annelids)
Vertebrate Circulatory SystemsVertebrate Circulatory Systems
TransportationTransportation Respiratory, nutritive, Respiratory, nutritive,
excretoryexcretory
RegulationRegulation Hormone transportHormone transport Temperature regulation Temperature regulation
(vasoconstriction/dilation, (vasoconstriction/dilation, countercurrent heat countercurrent heat exchange)exchange)
ProtectionProtection Blood clottingBlood clotting Immune defenseImmune defense
BloodBlood Composed of fluid plasmaComposed of fluid plasma
Interstitial fluid originates from plasma Interstitial fluid originates from plasma Matrix in which blood cells and Matrix in which blood cells and
platelets are suspendedplatelets are suspended Metabolites, wastes, hormonesMetabolites, wastes, hormones Ions Ions Proteins – carriers and clottersProteins – carriers and clotters
Red Blood Cell/ErythrocytesRed Blood Cell/Erythrocytes Oxygen transport, 45% of bloodOxygen transport, 45% of blood Doughnut shaped – increases surface Doughnut shaped – increases surface
areaarea Hemoglobin – pigmentHemoglobin – pigment
Develop from stem cellsDevelop from stem cells Plasma oxygen levels decrease, bone Plasma oxygen levels decrease, bone
marrow creates moremarrow creates more Mammalian – no nucleus, removed as Mammalian – no nucleus, removed as
ageage
White blood cells and plateletsWhite blood cells and platelets Immunological defensesImmunological defenses
Less than 1% of bloodLess than 1% of blood Larger, have nuclei, not confined to bloodLarger, have nuclei, not confined to blood Several types, each have specific jobSeveral types, each have specific job
Platelets – pieces of megakaryocytesPlatelets – pieces of megakaryocytes Injury – smooth muscle contracts, Injury – smooth muscle contracts,
constrictionconstriction Platelets accumulate, stick to each other via Platelets accumulate, stick to each other via
fibrinfibrin
Blood vesselsBlood vessels
Blood leaves heart via Blood leaves heart via arteries which branch to arteries which branch to reach organs, reach organs,
Finest branches are Finest branches are arterioles, enters arterioles, enters capillariescapillaries
Collected in venules led Collected in venules led to veinsto veins
Arteries, veins = same basic Arteries, veins = same basic structurestructure
Innermost = endothelium, Innermost = endothelium, elastic fibers, smooth elastic fibers, smooth muscle, connective tissue muscle, connective tissue layerlayer
Too thick to permit Too thick to permit exchangeexchange
Capillaries = only Capillaries = only endotheliumendothelium
Diffusion, filtration, Diffusion, filtration, transporttransport
Arteries and arteriolesArteries and arterioles Transport blood away from Transport blood away from
heartheart Larger arteries = more elastic Larger arteries = more elastic
fibersfibers Smaller = thick smooth muscleSmaller = thick smooth muscle Vast “tree” = frictional Vast “tree” = frictional
resistanceresistance Narrower vessel = more resistance Narrower vessel = more resistance
to flowto flow Regulated by constriction and Regulated by constriction and
dilationdilation Precapillary sphincters – limits heat Precapillary sphincters – limits heat
loss in coldloss in cold
Exchange in capillariesExchange in capillaries
Sufficient pressure needed to pump against Sufficient pressure needed to pump against resistanceresistance
Every cell is within 100 micromteres of a Every cell is within 100 micromteres of a capillarycapillary
Capillaries 1 millimeter long, 8 micro in diameterCapillaries 1 millimeter long, 8 micro in diameter Slightly wider than erythrocyte, must be flexibleSlightly wider than erythrocyte, must be flexible
Although narrow, number means greatest total area than any Although narrow, number means greatest total area than any vesselvessel
Blood has more time in capillaries, Blood has more time in capillaries, releases/pick-upreleases/pick-up
Loses pressure and velocity, is under low pressure in veinsLoses pressure and velocity, is under low pressure in veins
Venules and veinsVenules and veins
Venules-veins-heartVenules-veins-heart Less muscle because Less muscle because
less pressureless pressure Can expand to hold Can expand to hold
additional bloodadditional blood Skeletal muscles can Skeletal muscles can
contract to move blood contract to move blood back to heart – venous back to heart – venous pumppump
One way back to heart, One way back to heart, venous valvesvenous valves
Lymphatic SystemLymphatic System
Closed – all vessels connected with anotherClosed – all vessels connected with another Some water and solutes do filter through capillaries to form Some water and solutes do filter through capillaries to form
interstitial fluidinterstitial fluid Supplies tissue cells with oxygen and nutrientsSupplies tissue cells with oxygen and nutrients
Exits near arteriolar end where pressure is higher, re-Exits near arteriolar end where pressure is higher, re-enters by osmosis (oncotic pressure)enters by osmosis (oncotic pressure)
Lymphatic is open, returns rest of fluid to cardiovascularLymphatic is open, returns rest of fluid to cardiovascular Capillaries, vessels, nodes, organs including spleen and thymusCapillaries, vessels, nodes, organs including spleen and thymus Activate some white blood cellsActivate some white blood cells
Circulatory and respiratory Circulatory and respiratory adapatationsadapatations
Large body size and locomotion of animals Large body size and locomotion of animals possible because of coevolution of possible because of coevolution of systemssystems
Needed more efficient Needed more efficient
ways to transportways to transportCirculation and respirationCirculation and respiration
linkedlinked
Fish heartFish heart
Early chordates had Early chordates had simple tubular heartssimple tubular hearts
Gills of fish required Gills of fish required chamber-pump heartchamber-pump heart
Peristaltic sequence, Peristaltic sequence, heartbeat initiated by heartbeat initiated by electrical impulseelectrical impulse
Gills oxygenate blood, Gills oxygenate blood, but looses pressure but looses pressure developed by heart developed by heart contractioncontraction
Amphibian/reptilianAmphibian/reptilian Lungs – blood is oxygenated then Lungs – blood is oxygenated then
returned to heartreturned to heart Two circulations – pulmonary – heart/lungsTwo circulations – pulmonary – heart/lungs
Systemic – heart/bodySystemic – heart/body Separates oxygenated from deoxygenatedSeparates oxygenated from deoxygenated
Right atrium – receives deoxygenated Right atrium – receives deoxygenated from systemicfrom systemic
Left atrium receives oxygenated from Left atrium receives oxygenated from lungslungs
Little mixing in ventricleLittle mixing in ventricle Oxygenated blood to aorta, major arteryOxygenated blood to aorta, major artery
One ventricle with incomplete One ventricle with incomplete separationsseparations
Separation of pulmonary and systemic is Separation of pulmonary and systemic is incompleteincomplete
Amphibians can diffuse extra oxygenAmphibians can diffuse extra oxygen
Mammalian and BirdsMammalian and Birds Four chambered heartFour chambered heart
Two atria and two ventriclesTwo atria and two ventricles Right Right atriumatrium receives deoxygenated blood, delivers to receives deoxygenated blood, delivers to
right ventricle, which right ventricle, which pumpspumps to blood to lungs to blood to lungs Left atrium receives oxygenated blood from lungs, Left atrium receives oxygenated blood from lungs,
delivers to left ventricle, which delivers to left ventricle, which pumpspumps blood to body blood to body Occur simultaneously – increased efficiencyOccur simultaneously – increased efficiency Closed system – same amount of blood pumped by both Closed system – same amount of blood pumped by both
ventricles at same timeventricles at same time More pressure generated by left ventricleMore pressure generated by left ventricle
Sinus venosus – pacemaker Sinus venosus – pacemaker site of heartbeat impulsesite of heartbeat impulse
Major chamber in fishMajor chamber in fish Reduced through amphibians, Reduced through amphibians, reptilesreptiles Mammals/birds no longer Mammals/birds no longer separate chamber – tissue remains separate chamber – tissue remains in right atrium – sinoatrial (SA) in right atrium – sinoatrial (SA) nodenode
Cardiac cycleCardiac cycle Two separate pumping Two separate pumping
systems within one organsystems within one organ Two pairs of valvesTwo pairs of valves
Atrioventricular (AV) valves – Atrioventricular (AV) valves – guard openings between atria guard openings between atria and ventriclesand ventricles
Ttricuspid valve = exit Ttricuspid valve = exit of right atriumof right atrium
Bicuspid valve = exit Bicuspid valve = exit of left atriumof left atrium
Semilunar valves – guard Semilunar valves – guard openings between ventricles openings between ventricles and arteriesand arteries
Pulmonary – right ventricle Pulmonary – right ventricle to lungsto lungs
Aortic – left ventricle to bodyAortic – left ventricle to body Valves open and close during Valves open and close during
cardiac cycle cardiac cycle rest (diastole) and contraction rest (diastole) and contraction
(systole)(systole)
Blood returns to resting heart (diastole)Blood returns to resting heart (diastole) Deoxygenated blood into right atriumDeoxygenated blood into right atrium Oxygenated blood into left atriumOxygenated blood into left atrium
Ventricles contract (systole)Ventricles contract (systole) AV valves close (lub), push semilunar valves openAV valves close (lub), push semilunar valves open Ventricles relax, semilunar close (dub)Ventricles relax, semilunar close (dub)
http://www.nhlbi.nih.gov/health/dci/Diseases/hhw/hhw_pumping.html
Veins and arteriesVeins and arteries
Pulmonary arteries to Pulmonary arteries to lungslungs
Veins back to heartVeins back to heart
AortaAorta Superior vena cavaSuperior vena cava Inferior vena cavaInferior vena cava
Electrical excitationElectrical excitation
Heart contains specialized autogenic Heart contains specialized autogenic depolarizing cellsdepolarizing cells
Spreads from SA node to atria to ventriclesSpreads from SA node to atria to ventriclesRecorded on EKGRecorded on EKGLargest peak is polarization of ventriclesLargest peak is polarization of ventricles
http://www.nhlbi.nih.gov/health/dci/Diseases/hhw/hhw_electrical.html
Blood Flow and Blood PressureBlood Flow and Blood Pressure Cardiac output has normal Cardiac output has normal
resting rate (5L/minute)resting rate (5L/minute) Increases during exercise Increases during exercise
(25L/min)(25L/min) Vasoconstriction/dilation direct Vasoconstriction/dilation direct
extra blood to important areasextra blood to important areas Increased blood pressure = Increased blood pressure =
increase in heart rate or increase in heart rate or vasoconstrictionvasoconstriction Can be regulated by hormones Can be regulated by hormones
to increase blood volumeto increase blood volume
Blood Volume RegulationBlood Volume Regulation
ADH – antidiuretic, prevent dehydrationADH – antidiuretic, prevent dehydrationAldosterone – vasoconstrictionAldosterone – vasoconstrictionAtrial Natriuretic Hormone – release Na+ Atrial Natriuretic Hormone – release Na+
and waterand waterNitric Oxide – gas acts as a hormone - Nitric Oxide – gas acts as a hormone -
vasodilationvasodilation