Circulatory System

Transport systems in animals

Well be discussingFunctions of a transport/circulatory systemInvertebrate circulationDiffusionAided by gastrovascular cavityWater vascular systemOpen circulatory systemClosed circulatory systemVertebrate circulationFishesAmphibiansReptilesBirdsMammalsPathway of bloodCardiac cycleMaintenance of heartbeatPrinciples governing blood circulationLymphatic systemBlood composition and functionCardiovascular disease

Transports materialsNutrients from digested foodRespiratory gases: CO2 and O2Waste materials: toxins and nitrogenous wastesAntibodiesHormones EnzymesImmune functionsMaintains homeostasisBlood pHHeat transport

Functions of the circulatory system

How are materials transported in multicellular organisms?

Phylum Porifera

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How are materials transported in multicellular organisms?Gastrovascular cavity in simple invertebrates

Cnidarians (e.g. Hydra) and flatworms (e.g. planarians)No system requiredSingle opening: exchange of materials with the environmentCentral cavity for digestion and distribution of substances throughout the bodyBody walls two cell layers thick materials undergo diffusion

How are materials transported in multicellular organisms?Water vascular system in echinoderms

multi-purpose: locomotion, food and waste transport, respirationmovement of muscles pump water into canalsclosed system of canals connecting tube feetmadreporite ring canal radial and lateral canal tube feet ampullae

How are materials transported in multicellular organisms?

Open circulatory system

Phylum Arthropoda, Phylum Mollusca (with one exception)hemolymph heart(s) sinuses ostia heart(s)diffusion from sinuses to organsoften serve a support purposedisadvantage: loss of pressure in sinusesinsects: well-developed respiratory systems, O2 not transported through the blood

How are materials transported in multicellular organisms?Closed circulatory system or cardiovascular system

cephalopods, annelids, vertebratespresence of blood vesselsadvantagesrapid flowmay direct blood to specific tissuesblood cells and large molecules remain within vessels can support higher levels of metabolic activity

General plan of the cardiovascular systemHeartAtriumVentricleBlood vesselsArteriesArteriolesCapillaries and capillary bedsVenulesVeinsBlood

Vertebrate adaptations of the cardiovascular systemFISHESSingle-circulationFish heart2-chamberedatrium and ventricle

African lungfish heart3-chambered2 atriaLA: O2-rich bloodRA: O2-poor bloodspiral foldpartially divided ventricle

Vertebrate adaptations of the cardiovascular systemAmphibians

Pulmocutaneous and systemic circulation are partly separatedAmphibian heart1 ventricle2 atria:LA: O2-rich bloodRA: O2-poor bloodadvantage: oxygen-rich blood reaches the bodys organs fasterdisadvantage: some mixing of O2-rich and poor blood occurs

Vertebrate adaptations of the cardiovascular systemReptiles

Reptilian heart3-chambers (crocodilians have 4)2 atria1 ventricle (2 in crocodiles and alligators)partially divided, decreases mixing

Birds and Mammals4 chambered heart:2 atria2 ventriclesfull separation of pulmonary and systemic circuitsAdvantagesno mixing of oxygenated and deoxygenated bloodgas exchange is maximizedpulmonary and systemic circuits operate at different pressuresImportanceEndothermic high nutrient and O2 demands in tissuesNumerous vessels great deal of resistance, so requires high pressure

Vertebrate adaptations of the cardiovascular system

Blood flow in mammalsR side of heart:pulmonary circuitL side of heart:systemic circuit one way valves:atrioventricular valvessemilunar valves

right atrium receives O2-poor blood from superior and inferior venae cavaefrom right atrium into the right ventricle through the tricuspid valvepumped into the pulmonary artery through the pulmonary semilunar valve to lungsO2-rich blood from lungs is returned to the left atrium via the pulmonary veinsenters the left ventricle via the mitral or bicuspid valveexits the left ventricle into the aorta via the aortic semilunar valvecirculated to body tissues

Blood flow in mammals