Circulatory System by aR0YH3YN


 Up until now, we have discussed the;
   Digestive system
   Respiratory System

 We have seen how food is broken down to release and
 absorb nutrients
   And how waste is passed through the body

 We have seen how gases are exchanged
   To bring O2 into the body
   To remove CO2 from the body
              Circulatory System
 The bodies of animals and plants are very large
    It is difficult for nutrients and gases to make their way to all
     cells via diffusion

 A system to deliver these substances to all body tissues is
    Circulatory system

 Circulatory systems have the following functions
    Deliver nutrients to cells
    Take waste away from cells
      Components of the System
 All circulatory systems are made of these basic parts
    Blood
    Pump (heart)
    Arteries (take blood away from heart)
    Veins (take blood to the heart)
    Capillaries (allow nutrients and waste to diffuse in/out)
 Blood is made of several parts
    Plasma (the solution), containing
     all dissolved nutrients and waste
    White blood cells (for immune
    Red blood cells (to carry oxygen)

 Certain organisms do not transfer
  oxygen through their blood, and
  therefore do not have red blood
    Eg: Grasshoppers
 Earthworm Circulatory System
 The Earthworm has a relatively simple circulatory

 Five pseudohearts pump the blood around
    Pseudohearts are slightly enlarged blood vessels
    They continually contract and relax
    This motion pushes the blood around
 The blood flows through blood vessel through the body of
  the worm
 Oxygen and carbon dioxide are exchanged through the
  blood vessels running near the skin
 Fish have a slightly more complicated circulatory system

 Fish have a true heart
    With two chambers
    Atrium – Receives deoxygenated blood
    Ventricle – Pumps blood to the gills for oxygenation

     Atrium      From body

 The blood flows through the gills and then to the rest of
 the body
   Blood becomes rich in O2, low in CO2
   Gas exchange occurs capillaries
   Low O2, high CO2 blood returns to heart
 Which chamber of the heart is more likely more muscular?
   Atrium of ventricle?

 The ventricle is
    Because it pumps blood a much further distance (around the
     whole body)
    The atrium pumps blood into the ventricle only
 Capillaries are small blood vessels
    They spread out to reach all the cells
     in the area
    Gas and nutrient exchange occur
     here to feed the cells
    Waste is carried away from the cells

 All of the blood in the heart is
    Low oxygen concentration
 Amphibian Circulatory System
 Amphibians (and many reptiles) have a system that is
 similar to that of fish
   But there are some key differences

 Amphibians have three chambered hearts
    Two atriums
    One ventricle

 The oxygenated blood from the
 lungs mixes with deoxygenated
 blood from the body
 Ventricle pumps blood around the
   Some flows to the lungs
   Some flows around the body

 Oxygenated blood flows into the
   Mixes with deoxygenated blood from
    the other atrium

 What is the advantage of mixing the
 Mixing the blood together is
 advantageous because amphibians
 also breathe through their skin

 Mixing the blood ensures that the
 blood flowing through the body has
 some CO2 and some O2 in it
   Thus CO2 can diffuse out through the
   Blood will also gain more O2 as it
 This ensures that amphibians can
 breathe in and out of water
    Mammal Circulatory System
 Mammals have a four chambered heart
   There is complete separation of oxygenated and
    deoxygenated blood
   Both types of blood flow through the heart
         Four Chambered Heart

 Blood flows into the heart
 through the atria
   Left atrium from lungs
   Right atrium from the body

 Blood flows out of the heart
 from the ventricles
   Left ventricle to the body
   Right ventricle to the lungs
    Mammal Circulatory System
 The blood flowing to the body is
 totally oxygenated

 Blood flowing to the lungs is very

 This maximizes the amount of O2
 sent to the body cells

 This allows mammals to be very
                  Blood Vessels
 Arteries
    Flow away from the heart

 Veins
    Flow towards the heart
    Contain valves to prevent backwards
     flow of blood
           Varicose Veins
 Varicose veins occur when the
 valves in veins do not function
   Blood starts to pool
   Veins become enlarged and

 More common in women than
   Usually hereditary
 When blood vessel become
 narrowed due to a plague build
   Cholesterol is a large
    contributor to this

 Narrow blood vessels cause high
 blood pressure
   Can cause heart attacks
 Questions in the handout

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