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RodriguezChoi circulatory

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					Evolution of the Circulatory
          System
   Sora Choi & Miguel Rodriguez
               Introduction
• Circulatory system solves the problem of
  energy and material exchange between an
  organism and its environment
• As body types evolved, natural selection
  favored organism that evolved more efficient
  means of distribution/exchange
• Several ways of distribution in extant
  organisms
                  Overview
• Evolutionary trends in the circulatory system
  – Maximum organism size
  – Complexity
  – Colonization of land
  – Cephalization

• Anatomy of representative animals

• Anatomy of representative chordates
             Overview (cont.)
• Control of body temperature in vertebrates via
  circulatory system
  – Counter-current heat exchange
  – Peripheral tissue circulation
• Human heart function
  – Regulation of heart rhythm
  – Cardiac cycle
  – Blood pressure
      Evolutionary Trends (Size)
• Bigger size favors more developed circulatory
  system
• Diffusion requires short distances
     • Time constraints (time α dist2)
     • Tissue thickness
  – Complex/thicker tissues have an evolutionary
    advantage…
  – Organism with tissues more than a few
    millimeters thick would not survive with just a GV
    cavity…
 Evolutionary Trends (Complexity)
• Open vs. closed circulatory systems
   – Both solve the problem of diffusion distance
   – Both rely on blood pressure differences
   – Both consist of three major components
      • Circulatory fluid (blood/interstitial fluid/hemolymph)
      • Set of tubing (vessels including arteries/veins)
      • Muscular pump (muscular vessels or heart organ)


  Both have advantages and disadvantages…
          Open Circulatory System
       Advantages
• Lower pressure = lower
  required energy
• Less piping = lower
  building/maintenance
  costs (energy)
• Can function as
  hydrostatic skeleton
  Disadvantages
  See CCS advantages

                 http://farm1.static.flickr.com/93/233112287_dd39898847.jpg?v=0
             Closed Circulatory System
           Advantages
•    Higher pressure
•    Higher efficiency
•    Higher metabolism
•    Better at dealing with
     gravity

      Disadvantages
      See OCS advantages



    http://health-pictures.com/blood/images/blood-circulation.jpg
  Evolutionary Trends (Cephalization)
• Muscular vessels to hearts
  – Muscular vessels = more rapid/efficient transport
    of fluid
  – A muscular heart keeps a regular, “steady” flow
    circulating throughout the organism
  – Evolution would favor an organism with a regular
    supply of nutrients/method of waste exchange
    etc. (consider breathing)
  – Brain requires substantial blood flow…
 Evolutionary Trends (Complexity)
• Hearts with chambers
  – A single contractile mass induces flow “outwards”
    upon contraction
  – This flow is instantly reversed upon cessation of
    pressure
  – Reversal is not favorable
     • Inefficient
     • Mixes blood of varying qualities
  – Evolution would favor an organism that could
    segregate the contractile mass
 Evolutionary Trends (Complexity)
• Two types of chambers
  – Atria
      • Receive blood from the organism
      • Smaller, less powerful
  – Ventricles
      • Pump blood throughout organism
      • Larger, more muscular
• Varying arrangements evolved (1 or 2 of each)

   http://www.starsandseas.com/SAS_Images/SAS_Physiol_Images/SAS%20cardiopics/
   heart_chambers.jpg
        Evolutionary Trends (5 of 5)
• Double circulation
   – In organisms with two atria
     and 1 or 2 ventricles
   – Combination of 2 and 2
     allows for complete
     segregation of oxygen-
     rich/oxygen-poor blood
• Human beings exhibit a
  combination of the most
  complex trends…



http://www.dorlingkindersley-
uk.co.uk/static/clipart/uk/dk/exp_humanbody/exp_human056.jpg
 Basic Anatomy - Animals
                               •   Porifera
                               •   Cnidarian
                               •   Platyhelminthes
                               •   Nematoda
                               •   Mollusca
                               •   Annelid
                               •   Arthropoda
                               •   Echinodermata
                               •   Chordate

http://i.n.com.com/i/ne/p/2006/CnidarianClouds_400x600.jpg
 Porifera Cnidaria Platyhelminthes Nematoda Mollusca Annelid Arthropoda
                         Echinodermata Chordata

• Sponge
  – no tissues hence no circulatory system
  – simple body structure




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      http://www-tc.pbs.org/kcet/shapeoflife/imganim/porifera3.jpg
  Porifera Cnidaria Platyhelminthes Nematoda Mollusca Annelid Arthropoda
                          Echinodermata Chordata



• Jellyfish
   – no true circulatory system
   – thin body wall encloses gastro-vascular cavity
   – rely on diffusion across two-cell thick layer




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 Porifera Cnidaria Platyhelminthes Nematoda Mollusca Annelid Arthropoda
                         Echinodermata Chordata



• Flatworm
  – no true circulatory system

  – branched GV cavity

  – only one opening

  – branching and flat body shape ensure short                            Co
                                                                          Si
    diffusion distances                                                   La
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 Porifera Cnidaria Platyhelminthes Nematoda Mollusca Annelid Arthropoda
                         Echinodermata Chordata



• Nematode
  – no circulatory system
  – tiny size




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              http://www.bu.edu/gk12/eric/nematode.jpg
  Porifera Cnidaria Platyhelminthes Nematoda Mollusca Annelid Arthropoda
                          Echinodermata Chordata



• Snail
   – Open circulatory system
       • fluid for conveyance
       • branching vessels
       • heart muscle to provide pressure
   – blood + interstitial fluid = hemolymph
       • bathes organs directly
       • pumped into spaces surrounding organs (sinuses)
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                    stolen from http://seabarnacle.piczo.com/?g=50019046&cr=5
       Porifera Cnidaria Platyhelminthes Nematoda Mollusca Annelid Arthropoda
                               Echinodermata Chordata



    Octopus

    Active predators

    Highly intelligent

    Closed circulatory
    system

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http://www.greenexpander.com/wp-                                                Ce
content/uploads/2007/12/octopus.jpg
  Porifera Cnidaria Platyhelminthes Nematoda Mollusca Annelid Arthropoda
                          Echinodermata Chordata



• Earthworm
   – Closed circulatory system
       • Same basic parts as before
       • Blood is confined to vessels
   – Blood and interstitial fluid do
     NOT mix
       • diffusion occurs between
         blood and fluid (middle-
         man)
   – Muscular vessels function as
     “hearts”
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                                    http://www.infovisual.info/02/006_en.html
       Porifera Cnidaria Platyhelminthes Nematoda Mollusca Annelid Arthropoda
                               Echinodermata Chordata



    • Lobster
        – Open circulatory system




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http://stuff4restaurants.com/blog2/wp-content/uploads/2007/12/blobster.jpg
     Porifera Cnidaria Platyhelminthes Nematoda Mollusca Annelid Arthropoda
                             Echinodermata Chordata



• Grasshopper

http://
unive
rse-
revie
w.ca/
I10-
82-
grass
hopp
er.jpg                                                                        Co
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      Porifera Cnidaria Platyhelminthes Nematoda Mollusca Annelid Arthropoda
                              Echinodermata Chordata



   • Echinoderms




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http://www.marriedtothesea.com/062406/ATTENTION-SCIENTISTS.gif
  Porifera Cnidaria Platyhelminthes Nematoda Mollusca Annelid Arthropoda
                          Echinodermata Chordata



• Dog (Woof!)
   – Cardio-vascular system
       • Similar to earthworm
       • Muscular heart with
         chambers
   – Chambered heart
     segregates blood
       • oxygen-rich vs. oxygen-
         poor

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                    http://www.dog-health-guide.org/images/dogheart.gif
   Right Lung                                                            Left Lung




Right Atrium                                                               Left Atrium

   Right Ventricle                                                   Left Ventricle




  Diaphragm



      Chest Cavity, Housecat Cattus fattus- Biology 162 Lab – March 26, 2009
• Some Chordates have hemoglobin in the
  blood
• Increase in circulatory complexity
• water to land (lungs to increase O2)
• Separate pulmonary circulatory loop
• Amphibians 3-4 to chamber hearts
• Oxygenated to deoxygenated blood
     Basic Anatomy - Chordates
• Urochordata
  – Blood contains a high amount of lithium and
    vandium
  – It consists of a ventral heart and an open
    circulatory system




            http://www.mun.ca/biology/scarr/Sea_Squir
            t.gif
         Example of Urochordata
• Sea Squirt (closed open
  circulatory system )
   – Muscular region which
      pumps hemolymph
   – Flow of hemolymph
      reverses with every
      contraction
   – No central heart present




           http://media.eurekalert.org/release_graphics/ciona.jpg
                   Chephalochordata
 • Circulation is closed
 • No central heart is present,
   but consists of branches.
 • Main ventral and paired
   dorsal aorta.
 • Lack hemoglobin and is
   colorless.
 • Have atria cavity
 • The overall pattern of the
   circulatory system is
   distinctly vertebrate                # 7 : Circulatory system of the
                                           lancelets
http://www.answers.com/topic/lancelet
                                        http://en.wikipedia.org/wiki/Lancelet
                    Agnathans
• Simple two-chambered            • Due to the difficulty of
  heart for blood                   pushing blood through
  circulation                       so many sets of gills,
• The heart absorbs                 lampreys have a heart
  blood from within itself          weight to body weight
• As a result, the blood it         ratio second only to
  receives lacks oxygen             mammals
   – thus heart                   • Hagfishes: six hearts +
     metabolism relies on           open circulatory system
     lipids and is
     anaerobic
                   http://eugevir.tripod.com/ca/AgCi.html
                           Blood is pumped out of the
                           ventricle to the gills,
S                          whence it travels to the
This diagram shows         rest of the body, and then
the basic blood            returns to the atrium, from
flow of Agnathans,         which it is pumped to the
which has a 2-
chambered heart
                           ventricle and then back to
                           the gills

                       A dissection of the circulatory
                         system of a lamprey.

             http://eugevir.tripod.com/ca/AgCi.html
                           Basic Anatomy
• Chondricthes (sharks)                       • The circulatory system
          • Two chambered heart                 invades the
          • Closed Circulatory System           cartilaginous matrix.
•   The difference b/twn Chondricthyes and
    Osteichthyes is that chondricthyes have     This permits the local
    skeletons made of cartilage, not bone
                                                osteoblasts (bone-
     – Osteichthyans (bony
                                                forming cells) to
       fish)
                                                continue bone
         • In lower vertebrates,
           cartilaginous                        formation within the
           structures can                       cartilage and also
           become superficially                 recruits additional,
           calcified . Bony fish                circulating osteoblasts.
           are different
            Single circulation in fishes

• Salmon
   – Two chambered heart
     (derived from
     Chondrichthes)
   – Single circuit of blood
     flow
   – gills to the body back to
     the heart.
Single Circulation
The blood passes through the heart once in
each complete circuit

Blood entering the heart collects in the
atrium before transfer to the ventricle.

Contraction of the ventricle pumps blood to
the gills where there is a net diffusion of O2
into the blood and of CO2 out of the blood.

As blood leaves the gills, the capillaries
converge into a vessel that carries O2 rich
blood to capillary beds throughout the body

When blood flows through a capillary bed,
blood pressure drops significantly, but when
animals swim, their contraction+ relaxation
of their muscles help pace circulation in the
blood
                Amphibians
Frog
       Three-chambered heart
           (two atria and one ventircle)
       Two circuits of blood flow (adults)
       (pulmo-cutaneous and systemic)
       The gas exchange occurs both in the
       lungs and skin capillaries
            Breathe in the water.
     Basic Anatomy - Amphibians
• Relatively little mixing of oxygen-rich / oxygen-
  poor blood occurs in the single ventricle
  (clean)
  – A ridge within the ventricle diverts most (90%) of
    the O2 poor blood from the R- atrium into the
    pulmocutaneous circuit and most of the O2 rich
    blood from the L-atrium into the systemic circuit.
                    Iguana
• Three-chambered heart
• A septum partially divides the single ventricle
  reducing mixing of oxygen-rich and oxygen-
  poor blood.
• Gas exchange only occurs in the lungs
• Because their skin is no longer exchanging gas
  from the environment, the iguana is similar to
  the frog.
                            Humans
• Four-chambered heart
  – Segregates oxygen-rich
  and oxygen-poor blood
  – Gives higher
  blood pressure
  – O2 rich blood
  and O2 poor blood
  do not mix
     • Two ventricles & atria.
              http://www.cptc.edu/library/Bio%20118%20L   http://www.uaf.edu/pair/physics
              ecture%20Notes%20Rev%200105_files/ima       /images/circulation.gif
              ge139.jpg
http://universe-review.ca/I10-82-
circulatory.jpg

http://www.uaf.edu/pair/physics/images/circ
ulation.gif
• Fishes
  – Single circulation
  – Two chambered heart
• Amphibians
  – Double circulation
  – Three chambered heart
• Reptiles (Except Birds)
  – Double circulation
  – Three chambered heart
     • With a septum partially dividing the single ventricle
           – In Crocodilians, the septum is complete and the heart is 4-
             chambered
   • Mammals
       – Dual circuits operate simultaneously
       – The two ventricles pump almost in unison
            • Some blood traveling in the pulmonary circuit, the rest
              of the blood is flowing in the systematic circuit




http://www.uaf.edu/pair/physi
cs/images/circulation.gif
   Body Temperature Regulation
• Counter-current heat transfer
  – involves an “anti-parallel arrangement of blood vessels”
    known as a countercurrent heat exchanger.
  – arteries and veins are placed near each other
  – Warm blood goes through arteries, it transports heat to
    the colder blood returning from the boundaries in the
    veins.
      • Dolphins and geese are examples of a countercurrent
        system as well as sharks, bluefin tuna, swordfish,
        bumblebees, honeybees, and some moths.
    Body Temperature Regulation
• Peripheral tissue circulation
  – Sweating/ bathing moisten the skin enhance
    evaporative cooling.
  – Many terrestrial mammals have sweat glands
    which are controlled by the nervous system.
  – Animals have hair, fat and feathers.
• vasodilation/vasoconstriction
  – increase in the diameter of superficial blood
    vessels
   Body Temperature Regulation
• Vasodilation cont.
  – affect the surface of the body
  – increases the blood flow
• Vasoconstriction
  – Reduces blood flow and heat transfer by decreasing the
    diameter of superficial vessels
  – Ex. jackrabbits avoid overheating on scorching, and
    desiccated days.
         Heart Rhythm Regulation
• SA node
   – Wall of right atrium
   – Origin of impulse (myogenic)
• AV node
   – Wall between RA/RV
   – 0.1 second delay
• Two nerve sets compromise
  to control rate
• Hormones/body temp. also
  influence rate

                                    http://health.howstuffworks.com/heart4.htm
               Cardiac Cycle
• One complete sequence of pumping and filling
  (contraction and relaxation)
• Atrial contraction fills ventricles
• Atrial relaxation allows some blood to return
  while >
• Ventricular contraction pumps blood to
  lungs/body
• Ventricular relaxation allows for filling from
  atrial contraction
Blood Pressure
• Ventricular contraction
  creates pressure in the
  arteries
• This pressure travels
  throughout body and is felt
  as the pulse
• Systolic pressure = “active
  pressure”
• Diastolic pressure = “passive
  pressure”
           Human Heart Physiology

                        Hope this works




http://www.metacafe.com/watch/2342286/human_heart_functioning_3d_model/
Questions ???

				
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