• Exchange of Materials

  • Animal cells exchange material across their cell membrane

    • Fuels for energy

    • Nutrients

    • Oxygen

    • Waster

  • 1-cell organism

    • Diffusion

• Overcoming the limits of diffusion

  • Diffusion is not adequate for moving material across more than 1-cell barrier

• In Circulation

  • What needs to be transported

    • Nutrients and fuels

      • From digestive system

    • Respiratory gases

      • O2 and CO2 to and from gas exchange systems

        • Lungs

        • Gills

    • Intracellular waste

      • Waste products from cells

        • Water

        • Salts

        • Nitrogenous wastes

Urea

• Protective agents

  • Immune defenses

    • White blood cells

    • Antibodies

  • Blood clotting agents

  • Regulatory molecules

    • Hormones

• Circulatory Systems

  • All animals have:

    • Circulatory fluid

      • Blood

    • Tubes

      • Blood vessels

    • Muscular pump

      • Heart

• Open Circulatory System

  • Taxonomy

    • Invertebrates

      • Insects

      • Arthropods

      • Mollusks

  • Structure

    • No separation between blood and interstitial fluid

      • Hemolymph

• Closed Circulatory System

  • Taxonomy

    • Invertebrates

      • Earthworms

      • Squid

      • Octopuses

    • Vertebrates

  • Structure

    • Blood confined to vessels and separate from interstitial fluid

      • 1 or more hearts

      • Large vessels to smaller vessels

      • Material diffuses between blood vessels and interstitial fluid

• Adaptations in a Closed System

  • Number of heart chambers differs

• Evolution of a 4-chambered Heart

  • Selective forces

    • Increased body size

      • Protection from predation

      • Bigger body = bigger stomach for herbivores

    • Endothermy

      • Can colonize more habitats

    • Flight

      • Decrease population and increase prey capture

  • Effect of higher metabolic rate

    • Greater need for energy, fuels, oxygen, and waste removal

      • Endothermic animals need 10x more energy

      • Need to deliver 10x fuel and oxygen to cells

• Vertebrate Cardiovascular System

  • Chambered heart

    • Atrium

      • Receive blood

    • Ventricle

      • Pump blood out

    • Blood vessels

      • Arteries

        • Carry blood away from heart

      • Veins

        • Return blood to heart

      • Cappilarries

        • Thin wall

        • Exchange/diffusion

Capillary beds = networks of capillaries

• Arteries

  • Built for high pressure pump

  • Thicker walls

    • Provide strength for high pressure pumping of blood

  • Narrow diameter

  • Elasticity

    • Elastic recoil helps maintain blood pressure even when the heart relaxes

• Veins

  • Built for low pressure flow

  • Thinner-walled

  • Wider diameter

    • Blood travels back to the heart at a low velocity and pressure

    • Lower pressure

      • Distant from heart

      • Blood must flow by skeletal muscle contractions when we move

        • Squeeze blood through veins

    • Valves

      • In larger veins, there are one-way valves that allow blood to flow only toward the heart

• Capillaries

  • Built for exchange

  • Very thin walls

    • Lack 2 outer wall layers

    • Only endothelium

      • Enhances exchange across capillaries

    • Diffusion

      • Exchange between blood and cells

• Lymphatic System

  • Parallel circulatory system

    • Transports white blood cells

      • Defending against infection

    • Collects interstitial fluid and returns blood

      • Maintains volume and protein concentration of blood

      • Drains into circulatory system near the junction of the vena cava and right atrium

• Heart Valves

  • 4 valves in the heart

    • Flaps of connective tissue

    • Prevent backflow

  • Atrioventricular valve

    • Between atrium and ventricle

    • Keeps blood from flowing back into atria when ventricles contract

  • Semilunar valves

    • Between ventricle and arteries

    • Prevent backflow from arteries into ventricles while they are relaxing

• Heart Sounds

  • Closing of valves

    • “Lub”

      • Recoil of blood against close atrioventricular valves

    • “Dub”

      • Recoil of blood against the semilunar valves

  • Heart murmur

    • Defect in valves cause hissing sound when a stream of blood squirts backward through the valve

• Cardiac Cycle

  • 1 complete sequence of pumping

    • Heart contracts and pumps

    • Heart relaxes and chamber fill

    • Contraction phase

      • Systole

      • Ventricles pump blood out

    • Relaxation phase

      • Diastole

      • Atria refill with blood