Circulatory SystemCirculatory System

circulatory system circulatory system transports Otransports O22 and nutrients to cells and nutrients to cells takes away COtakes away CO22 and other wastes and other wastes

Circulatory System: Circulatory System: Gastrovascular CavityGastrovascular Cavity

Gastrovascular cavity – no need for Gastrovascular cavity – no need for circulatory system cnidarian & flatwormscirculatory system cnidarian & flatworms

Circulatory System:Circulatory System:Open vs ClosedOpen vs Closed

Open systemsOpen systems Heart pumps blood through open-ended Heart pumps blood through open-ended

vessels into spaces between cellsvessels into spaces between cells

Circulatory System:Circulatory System:ClosedClosed

Closed systemsClosed systems Heart pumps blood through arteries and Heart pumps blood through arteries and

capillary bedscapillary beds Blood returns to heart via veinsBlood returns to heart via veins

Circulatory System: Circulatory System: Heart ChambersHeart Chambers

Fish = 2 chambers (atrium, ventricle)Fish = 2 chambers (atrium, ventricle) Amphibians / Reptiles = most have 3 Amphibians / Reptiles = most have 3

chambers (2 atria, 1 ventricle); chambers (2 atria, 1 ventricle); crocodiles are exception, have 4 crocodiles are exception, have 4 chamberschambers

Birds / Mammals = 4 chambers (2 Birds / Mammals = 4 chambers (2 atria, 2 ventricle)atria, 2 ventricle)

Circulatory System:Circulatory System:Heart Chambers in Different Heart Chambers in Different

AnimalsAnimals

Circulatory System:Circulatory System:Blood VesselsBlood Vessels

Artery = AWAY Artery = AWAY from heart / from heart / thick muscle thick muscle and tissueand tissue

Veins = Veins = Towards heart / Towards heart / valvesvalves

Capillaries = Capillaries = where diffusion where diffusion occurs / thin occurs / thin epithelial liningepithelial lining

Circulatory System: Circulatory System: Blood VesselsBlood Vessels

CapillariesCapillaries VeinsVeins

Circulatory System:Circulatory System:CircuitsCircuits

Pulmonary Pulmonary circuitcircuit Heart <-> lungs Heart <-> lungs

(or equivalent) (or equivalent) Systemic circuitSystemic circuit

Heart <-> bodyHeart <-> body

Circulatory System:Circulatory System:Mammal HeartMammal Heart

Atria (top)Atria (top) Ventricles (bottom)Ventricles (bottom) Valves (AV/ SL)Valves (AV/ SL) Aorta / Inferior and Aorta / Inferior and

Superior Vena Superior Vena CavaCava

Pulmonary Pulmonary Artery/VeinArtery/Vein

Circulatory System: Path of Circulatory System: Path of BloodBlood

Circulatory System: Cardiac Circulatory System: Cardiac CycleCycle

Diastole: Diastole: relaxed and relaxed and blood flows inblood flows in

Systole - Systole - contractcontract AtriaAtria ventriclesventricles

Circulatory System:Circulatory System:PacemakerPacemaker

SA node (pacemaker) sends electrical SA node (pacemaker) sends electrical signals signals contraction of the atriacontraction of the atria

AV node AV node ventricles ventricles

Circulatory System: Blood Circulatory System: Blood PressurePressure

Pressure: Pressure: highest in highest in arteries arteries (therefore, (therefore, thickest blood thickest blood vessel)vessel) Drops to zero Drops to zero

when blood when blood reaches veinsreaches veins

120/80120/80

Figure 23.13

Withdrawblood

Place in tube

PLASMA 55%

CONSTITUENT MAJOR FUNCTIONS

WaterSolvent forcarrying othersubstances

Salts

Osmotic balance,pH buffering, andregulation ofmembranepermeability

SodiumPotassiumCalciumMagnesiumChlorideBicarbonate

Plasma proteins

Osmotic balance,pH bufferingClottingImmunity

Albumin

FibrinogenImmunoglobins(antibodies)

Substances transported by bloodNutrients (e.g., glucose, fatty acids, vitamins)Waste products of metabolismRespiratory gases (O2 and CO2)Hormones

Centrifuge

CELLULAR ELEMENTS 45%

CELL TYPE NUMBER(per mm3 of blood)

FUNCTIONS

Erythrocytes(red blood cells) 5–6 million Transport of

oxygen (and carbon dioxide)

Leukocytes(white blood cells) 5,000–10,000

Defense andimmunity

Basophil

Eosinophil

Neutrophil

Lymphocyte

Monocyte

Platelets 250,000–400,000

Blood clotting

Circulatory System: Circulatory System: Erythrocytes (RBC)Erythrocytes (RBC)

Red blood cells Red blood cells contain hemoglobin contain hemoglobin Hemoglobin enables Hemoglobin enables

transport of O transport of O22

No nucleus so No nucleus so maximize room for maximize room for hemoglobinhemoglobin

Few months life Few months life spanspan

Circulatory System: Leukocytes Circulatory System: Leukocytes (WBC)(WBC)

White blood cells White blood cells function both inside function both inside and outside and outside circulatory system circulatory system Fight infections and Fight infections and

cancercancer

Circulatory System: Circulatory System: Platelets & ClottingPlatelets & Clotting

platelets – clotting when vessels platelets – clotting when vessels damageddamaged Help make fibrin (web) for clotHelp make fibrin (web) for clot

Circulatory System:Circulatory System:Blood TypeBlood Type

Circulatory System: Blood Circulatory System: Blood TypeType

Blood Type Receive From Give to

 A 

 A, O

 A, AB

 B

 B, O

 B, AB 

 AB

 A, B, AB, O

 AB

 O

 O

 A, B, AB, O