Upload
shiela
View
19
Download
0
Tags:
Embed Size (px)
DESCRIPTION
CIRCULATION AND GAS EXCHANGE. Circulation in Animals. Transport systems functionally connect the organs of exchange with body cells. Diffusion is too slow. By rapidly transporting fluid in bulk it connects the aqueous environment of cells to organs of gas exchange. - PowerPoint PPT Presentation
Citation preview
Circulation in AnimalsCirculation in AnimalsTransport systems functionally Transport systems functionally
connect the organs of exchange with connect the organs of exchange with body cells.body cells.Diffusion is too slow.Diffusion is too slow.By rapidly transporting fluid in bulk it By rapidly transporting fluid in bulk it
connects the aqueous environment of connects the aqueous environment of cells to organs of gas exchange.cells to organs of gas exchange.
Nutrients are absorbed and wastes are Nutrients are absorbed and wastes are taken away.taken away.
Invertebrate Nutrient and Gas Invertebrate Nutrient and Gas ExchangeExchange
Gastrovascular CavitiesGastrovascular CavitiesSimple organisms with few layers Simple organisms with few layers
absorb nutrients through pockets in absorb nutrients through pockets in their bodies.their bodies.
Extra-cellular digestion occurs to break Extra-cellular digestion occurs to break down larger particles.down larger particles.
Cnidarians, Planarians, and PoriferaCnidarians, Planarians, and PoriferaCirculation unnecessary because all Circulation unnecessary because all
cells are exposed to the environment.cells are exposed to the environment.
Cnidarians
Open Circulatory Open Circulatory SystemsSystems Open circulatory system Open circulatory system
Blood bathes organs directlyBlood bathes organs directly Arthropods and most mollusksArthropods and most mollusks No distinction between blood and interstitial No distinction between blood and interstitial
fluid.fluid. Body fluid called hemolymph.Body fluid called hemolymph. Sinuses are spaces around organs.Sinuses are spaces around organs. One or more hearts pull blood in through One or more hearts pull blood in through ostia.ostia. Blood squeezed around the body through Blood squeezed around the body through
movement.movement.
Closed Circulatory Closed Circulatory SystemSystem
Blood is confined to vessel and distinct Blood is confined to vessel and distinct from interstitial fluid.from interstitial fluid.
Earth worms and higher animals.Earth worms and higher animals. Vertebrates have a cardiovascular system.Vertebrates have a cardiovascular system.
Atrium – top chamber of the heartAtrium – top chamber of the heart Ventricle- lower chamber of the heart.Ventricle- lower chamber of the heart. Arteries – direct blood away from the heart.Arteries – direct blood away from the heart. Veins direct blood to the heart.Veins direct blood to the heart. Capillary beds infiltrate each tissue.Capillary beds infiltrate each tissue.
Route of Blood Through the Route of Blood Through the BodyBody
Systemic circuitSystemic circuit – delivers blood to – delivers blood to the body.the body.
Pulmonary circuitPulmonary circuit – picks up blood – picks up blood from pulmonary organs and delivers from pulmonary organs and delivers it back to the heart.it back to the heart.
Fish HeartFish HeartFishFish
Two chambersTwo chambersSingle circulation which means blood Single circulation which means blood
must travel through two capillary beds must travel through two capillary beds before it returns to the heart.before it returns to the heart.
Because pressure drops in the capillary Because pressure drops in the capillary bed, blood flow is much slower than in bed, blood flow is much slower than in other organisms.other organisms.
AmphibianAmphibian HeartHeart Three chambersThree chambers
Two atria and one ventricleTwo atria and one ventricle A ridge separates most of the oxygenated from A ridge separates most of the oxygenated from
the deoxygenated blood, however some mixing the deoxygenated blood, however some mixing does occur.does occur.
Double circulationDouble circulation Blood returns to the heart after picking up Blood returns to the heart after picking up
oxygen. Sustains a higher pressure.oxygen. Sustains a higher pressure. Pulmocutaneous circuit.Pulmocutaneous circuit. Pulmonary organs are the lungs and skin.Pulmonary organs are the lungs and skin.
ReptilesReptiles Three chambers clearly dividedThree chambers clearly divided Have a pulmonary circuitHave a pulmonary circuit
Mammalian HeartMammalian HeartTwo atria and two ventriclesTwo atria and two ventriclesDistinct separation of oxygen and Distinct separation of oxygen and
deoxygenated blood.deoxygenated blood.Double circulation with a pulmonary Double circulation with a pulmonary
circuit.circuit.
Mammalian Cardiac Mammalian Cardiac CycleCycle
Cardiac CycleCardiac Cycle - One complete pumping - One complete pumping and filling.and filling.
SystoleSystole – contraction phase of the cycle – contraction phase of the cycleDiastoleDiastole – relaxation phase of the cycle. – relaxation phase of the cycle.Cardiac OutputCardiac Output – the volume of blood – the volume of blood
that the left ventricle pumps into the that the left ventricle pumps into the systemic circuit per minute.systemic circuit per minute.Depends on two factors:Depends on two factors:
Heart rate - rate of heart beat.Heart rate - rate of heart beat.Stroke volume – blood pumped from left ventricle Stroke volume – blood pumped from left ventricle
per contraction.per contraction.
Average stroke volume for humans is Average stroke volume for humans is 75 ml with a cardiac output of about 75 ml with a cardiac output of about 5.25 L/min. and an average pulse of 5.25 L/min. and an average pulse of 70 beats per minute.70 beats per minute.
Exercising increases stroke volume Exercising increases stroke volume because the heart beats more because the heart beats more efficiently.efficiently.More blood pumped to the systemic More blood pumped to the systemic
circuit per contraction.circuit per contraction.
The “Lub The “Lub Dub”Dub” Atrioventricular valvesAtrioventricular valves
Separate atria from ventricles.Separate atria from ventricles. Semilunar valvesSemilunar valves
Present at both exits of the heart.Present at both exits of the heart. Heart MurmurHeart Murmur
Defect in the valves.Defect in the valves. ““Lub” Lub”
Recoil of blood against closed atrioventricular Recoil of blood against closed atrioventricular valves.valves.
““Dub”Dub” Recoil of blood against closed semilunar valvesRecoil of blood against closed semilunar valves
Maintaining the BeatMaintaining the Beat Sinoatrial NodeSinoatrial Node
Located in the right atrium near the Superior Located in the right atrium near the Superior Vena Cava.Vena Cava.
Sets the tempo for contraction.Sets the tempo for contraction. Stimulates atrium to contract in unison.Stimulates atrium to contract in unison. Orchestration of muscle cells accomplished Orchestration of muscle cells accomplished
through intercalated discs.through intercalated discs. Perkunji FibersPerkunji Fibers
Transmit electrical signal.Transmit electrical signal. 0.1 second delay allows atria to completely 0.1 second delay allows atria to completely
empty before the ventricles contractempty before the ventricles contract
Maintaining the Maintaining the BeatBeat
Atriovenricular NodeAtriovenricular NodeCauses the ventricles to contract.Causes the ventricles to contract.
Factors That Affect Heart RateFactors That Affect Heart RateBody temperatureBody temperature
11oo F increase increases heart rate by 10 F increase increases heart rate by 10 beats/min.beats/min.
ExerciseExerciseHormonal stimulation.Hormonal stimulation.
Epinephrine –speeds up heart rate.Epinephrine –speeds up heart rate.
ArteriesArteriesThicker wallsThicker walls
Outer wall connective tissue with elastic Outer wall connective tissue with elastic fibersfibers
Middle layer smooth muscle – peristalsisMiddle layer smooth muscle – peristalsisInner wall – Inner wall – Endothelium Endothelium , composed of , composed of
smooth flat cells to reduce resistance to smooth flat cells to reduce resistance to blood flow. blood flow.
VeinsVeinsThinner than arteries.Thinner than arteries.Valves to prevent back flow.Valves to prevent back flow.Blood moves through by muscle Blood moves through by muscle
contractions.contractions.Virtually all pressure from ventricular Virtually all pressure from ventricular
contraction is gone.contraction is gone.
CapillariesCapillaries Lack outer and middle layers.Lack outer and middle layers.
Basement membrane with endothelial layer.Basement membrane with endothelial layer. Designed for gas and nutrient exchange Designed for gas and nutrient exchange
between blood and interstitial fluid.between blood and interstitial fluid. Blood flows 1000 times slower than in Blood flows 1000 times slower than in
arteries and veins due to a large surface arteries and veins due to a large surface area. area. Facilitates gas exchange.Facilitates gas exchange.
Pressure drops dramatically in capillary Pressure drops dramatically in capillary bedsbeds
Blood PressureBlood Pressure Hydrostatic pressure pushes blood through Hydrostatic pressure pushes blood through
blood vessels.blood vessels. Systole Systole – pressure due to ventricular – pressure due to ventricular
contraction.contraction. Arteries stretch because blood flows out much Arteries stretch because blood flows out much
more quickly than it can leave the artery.more quickly than it can leave the artery. Diastole – pressure due to the arterial wall Diastole – pressure due to the arterial wall
”snapping back”.”snapping back”. Next contraction occurs before all blood has Next contraction occurs before all blood has
left the artery and maintains pressure flow.left the artery and maintains pressure flow.
Blood pressure determined by:Blood pressure determined by:Cardiac outputCardiac outputPeripheral resistancePeripheral resistance
Contraction of atrioles creates peripheral Contraction of atrioles creates peripheral resistance.resistance.
Contractions triggered by stress, hormones, Contractions triggered by stress, hormones, and nicotine.and nicotine.
Exercise increases cardiac output and dilates Exercise increases cardiac output and dilates atrioles to supply blood to the muscles.atrioles to supply blood to the muscles.
Giraffes and probably dinosaurs have Giraffes and probably dinosaurs have valves and sinuses in their brain and valves and sinuses in their brain and neck to prevent a stroke while bending neck to prevent a stroke while bending down for a drink.down for a drink.
Gas Exchange in the Gas Exchange in the CapillariesCapillaries
OO22 and CO and CO2 2 diffuse down their gradient.diffuse down their gradient. Hydrostatic pressure on the atriole end Hydrostatic pressure on the atriole end
forces 80% of the fluid out into the tissues.forces 80% of the fluid out into the tissues. Large proteins and blood cells left behind Large proteins and blood cells left behind
increases the osmolarity of the blood.increases the osmolarity of the blood. Causes fluid to move back into the Causes fluid to move back into the
capillaries at the venule end.capillaries at the venule end. Fluid that doesn’t make it back into the Fluid that doesn’t make it back into the
cappilarie(15%) is returned to the blood cappilarie(15%) is returned to the blood through the lymphatic system.through the lymphatic system.
Lymph VesselsLymph Vessels Lymph fluid composition about the same Lymph fluid composition about the same
as interstitial fluid.as interstitial fluid. Moves through the body by squeezing of Moves through the body by squeezing of
skeletal muscles and peristalsis.skeletal muscles and peristalsis. Valves prevent back flow.Valves prevent back flow. Lymph returns fluid that has leaked out in Lymph returns fluid that has leaked out in
capillary beds to the circulatory system capillary beds to the circulatory system near the right atrium.near the right atrium.
Lymph contains white cells that attack Lymph contains white cells that attack bacteria and viruses.bacteria and viruses.
PlasmaPlasmaComposition of PlasmaComposition of Plasma
90% H90% H22O, inorganic salts (electrolytes) O, inorganic salts (electrolytes) PH about 7.4PH about 7.4Plasma proteinsPlasma proteins
BuffersBuffersFibrinogen (clotting)Fibrinogen (clotting)Proteins that escort lipids which are insoluble Proteins that escort lipids which are insoluble
in water.in water.HormonesHormonesViscosity proteinsViscosity proteins
Kidneys maintain electrolytes.Kidneys maintain electrolytes.
ErythrocytesErythrocytes Biconcave for more surface area.Biconcave for more surface area. Lack mitochondria and nuclei – more room Lack mitochondria and nuclei – more room
for hemoglobin.for hemoglobin. molecules of hemoglobin per cell.molecules of hemoglobin per cell. Generate ATP through anaerobic Generate ATP through anaerobic
metabolism.metabolism. Kidneys produce Kidneys produce erythropoietinerythropoietin to to
stimulate the function of Red blood cells.stimulate the function of Red blood cells. Hemoglobin also binds NO to relax Hemoglobin also binds NO to relax
capillaries.capillaries.
RBC’S, Neutrophils
Blood PressureBlood Pressure Hydrostatic pressure pushes blood through blood Hydrostatic pressure pushes blood through blood
vessels.vessels. Highest during ventricular contraction.Highest during ventricular contraction.
During During systolesystole blood is pushed out into the artery faster blood is pushed out into the artery faster than it can leave the artery.than it can leave the artery.
During During diastolediastole artery “snaps back” and creates residual artery “snaps back” and creates residual pressure in the arteries to continue pushing blood pressure in the arteries to continue pushing blood through.through.
Blood pressure is determined by Blood pressure is determined by cardiac outputcardiac output and and peripheral resistanceperipheral resistance..
Stress contracts blood vessels and raises blood Stress contracts blood vessels and raises blood pressure.pressure.
Exercise causes atrioles to dilate causing more Exercise causes atrioles to dilate causing more blood to flow in. A drop in pressure occurs and the blood to flow in. A drop in pressure occurs and the cardiac output increases to compensate.cardiac output increases to compensate.
Cardiovascular Cardiovascular DiseaseDisease
ThrombusThrombus – blood clot. – blood clot. EmbolusEmbolus – when clot breaks off and moves – when clot breaks off and moves
elsewhere in the body.elsewhere in the body. When a clot blocks a coronary artery – When a clot blocks a coronary artery –
myocardial infarctionmyocardial infarction.. AtherosclerosisAtherosclerosis – plaques form on the – plaques form on the
inner wall of the artery.inner wall of the artery. ArteriosclerosisArteriosclerosis – when plaques harden – when plaques harden
through calcification.through calcification. Angina PectorisAngina Pectoris – heart pain that signals – heart pain that signals
that the heart is not getting enough that the heart is not getting enough oxygen.oxygen.
HypertensionHypertensionHigh Blood PressureHigh Blood Pressure
Causes chronic abuse of the Causes chronic abuse of the endothelium and encourages plaque endothelium and encourages plaque formation.formation.
Narrows the lumen of the blood vessels Narrows the lumen of the blood vessels and reduces elasticity of blood vessels.and reduces elasticity of blood vessels.
Can compromise arterial walls and Can compromise arterial walls and increase risk for embolisms and increase risk for embolisms and aneurisms.aneurisms.
Plaque Build-Up in Blood Vessels