The Circulatory System

Open circulatory system• “Blood” is emptied into the body cavity

• Advantage over open CS– Delivers blood to

depth of organ more efficiently

• Disadvantage of 2 chambers– Lack of pressure to

transport blood

Evolution of heart

• Additional atrium

• Benefit– Increases

pressure – But not enough

to provide O2 for long distance travel

Inferior Vena cava

Superior Vena cava

Subclavian VeinBrachiocephalic Vein

Renal Vein

Pulmonary Artery

Pulmonary Vein

Left Carotid Artery

BrachiocephalicArtery

Jugular Vein

Closed Circulatory Systems

• Two sections for gas exchange– Pulmonary – Systemic

• One location for pumping blood– Two chambers• Receiving : Atrium

– Coming in from veins• Pumping : Ventricle

– Going Away Arteries

• Problems with this design?

Closed Circulatory Systems• 2 sections for gas exchange• 1 location for pumping

blood– Three chambers

• Receiving : Atria– Right A. Coming in from body

veins– Left A. Coming in from lungs

• Pumping : Ventricle– Going Away to body – Going Away to lungs

• Problem with Design? • Advantages?

Closed Circulatory Systems

• Four chambers– Receiving : Atria

• Right A. Coming in from body veins

• Left A. Coming in from lungs

– Pumping : 2 Ventricles• Left V: Going Away to body • Right V. Going Away to lungs

•

Fetal Pig Circulatory System