The Human Body Circulatory System

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					The Human Body:
Circulatory System

Textbook Chapter 34
Review Book Topic 1

   Cells must:
    – Have oxygen and nutrients

    – Be able to get rid of waste products

    – Be able to regulate and distribute heat
      throughout the body to regulate internal
   Transport system
    – Blood
          Carries important substances to all parts of the

    – Heart
          Pumps blood through a network of tubes
           throughout your body

    – Blood vessels
          Network of tubes carrying blood to all parts of the

    – Lymphatic system
          Part of circulatory and immune systems
Blood Vessels

   Circulate blood throughout the body

   Help keep the blood flowing to and from the

   Can expand to allow more blood flow, or
    contract to restrict blood flow
   Arteries
    – Carries oxygen-rich blood away from the
      heart to organs and tissues of the body

    – Large in size, strong, thick-walled, elastic,
      durable smooth muscle

    – Can withstand high pressures exerted from
      pumping of the heart
   Capillaries

    – Arteries branch out through the body
      becoming smaller and smaller in diameter
      (like the branches of a tree)

    – Smallest branches are known as capillaries
– Microscopic blood vessels only one cell

– Exchange of important substances and
  wastes occurs between blood and body
   Veins
    – Largest blood vessels

    – Thin walled and less elastic

    – Transfers deoxygenated blood from
      capillaries back to the heart

    – Decreased blood pressure
– Skeletal muscles are used to pump blood back
  to the heart

– Valves prevent blood from moving backwards

– Varicose vein – forms when the valves are
  faulty causing blood to buildup and stretch
  the vein’s walls
   Hallow muscular organ

   Size of your fist

   Located in center of your chest

   Pumps blood throughout your body
    – Oxygenated blood to your body
    – Deoxygenated blood to your lungs
Heart Structure

   Made of cardiac muscle

   Capable of conducting an electrical
    impulse for muscle contraction

   Pericardium – tough, protective
    membrane located around the heart
   Four compartments known as chambers
    – Right and left atrium
        Receiveblood returning to the heart
        through the veins

    – Right and left ventricle
        Pump  blood away from the heart through
        the arteries
   Muscular wall separates left and right sides of
    the heart (septum)

   Valves are used to keep blood flow in one

    – Found between each ventricle and in large blood
      vessels carrying blood away from the heart

    – Heart murmurs are caused by a leaky valve
Heart Dissection

   Use your diagram to follow along with
    the deer heart which we will use as
    our model
Heart Function

   Two phases

    – Atria fill with blood then contract, filling
      ventricles with blood (“lubb”)

    – Ventricles contract to pump blood out of the
      heart, into the lungs or forward into the body
   Regular rhythm
    – Pacemaker node (SA)
      controls heart beat

        Regulates  the
        electrical impulses sent for cardiac muscle
        contraction in atria

        Found   on top of right atrium
        Sends out signal to atrioventricular node
        (AV), causing ventricles to contract

        Artificial

        can be used to
        regulate heart

   This two step
    contraction (SA to AV
    nodes) represents one complete heartbeat
   Pulse
    – Pulses 70 times a
      minute on average

    – Created by alternating expansion and
      relaxation of the artery caused by the
      contraction of the left ventricle

    – Number of times the artery pulses is the
      number of times your heart beats
   Blood pressure

    – Measured of
      how much
      pressure is
      against the
      vessel walls
      by the blood
– Systole – contraction of the heart causes
  blood pressure to rise to its highest point

– Diastole – relaxation of the heart brings
  blood pressure to its lowest point

– Normal healthy adult blood pressure ~
  120(systolic pressure)/80(diastolic pressure)
Blood Flow

   Two loops

    – Heart to lungs then back to heart

    – Heart through body then back to heart
   “Heart-Lung Loop”
    – Deoxygenated blood from the body flows into
      the right atrium with a high concentration of
      carbon dioxide (waste)

        Dark   red to almost blue/purple color

    – Flows into the right ventricle and is pumped into
      the pulmonary arteries leading to the lungs
– Blood flows into capillaries in the lungs which
  are in close contact with air brought into the
  lungs from inhalation

– Air has more dissolved oxygen (high) than
  blood (low) so it diffuses into the blood
– Opposite for carbon dioxide which diffuses out
  of the blood and into the lungs for exhalation

– Oxygenated blood flows to the left atrium of the
  heart to be pumped out to the body

    Bright   red
   “Heart-Body Loop”
    – Left atrium fills with oxygenated blood from the

    – Blood moves into the left ventricle where it is
      pumped to the body out of the largest artery
      called the aorta

    – Blood flows through arteries, into capillaries
      which branch throughout the body
– Oxygen is released into the body cells by

– Carbon dioxide (wastes) moves from the
  cells to the blood by diffusion

– Deoxygenated blood then flows back to the
  right atrium through the veins
   Heart Blood Flow Animation

   Circulatory System BrainPop

   Heart BrainPop
Blood Components
   Contains living cells that transport important
    substances throughout the body

   Composition
     – Plasma
     – Red blood cells
     – White blood cells
     – Platelets
   Plasma
     – Clear, yellowish fluid

    – 50% of blood
        90%   is water/10% dissolved materials

    – Carries the breakdown products from
      digested food, vitamins, minerals, chemical
      messengers, cell wastes
– Contains proteins

   Regulate amount of
   water in the blood

   Form   blood clots
   Red blood cells
    – Carry oxygen to all of the body’s

    – Resemble discs with pinched-in

    – Develop in bone marrow

    – Have no nuclei
– Live for 120 days

– Consists mostly of hemoglobin
   Iron-containing   protein
   Oxygen   binds to protein for transport
   White blood cells

    – Body’s disease fighters

    – Produced in bone marrow

    – Can recognize disease-causing organisms
      and alert the body’s immune system

    – Produce chemicals to fight off “invaders”
      while surrounding and killing them
– Move from the bone marrow to other sites in the
  body to mature (unlike RBCs)

– Fewer in number than RBCs

   1WBC for every 500-1000

– Have nuclei

– Live for months to years
   Platelets
    – Cell fragments that form blood clots

        Collectand stick to a broken blood
        vessel, releasing fibrin (protein)
        that produces a weave of fibers
        across the cut to trap blood
        platelets and red blood cells

        Clots form when platelets and red
        blood cells are trapped in the
   Blood BrainPop
Common Disorders
   Atherosclerosis – blocked arteries resulting in
    high blood pressure, high cholesterol levels,
    increases stress on the heart and blood vessels

    – Can lead to a heart attack or stroke

        Heart attack affects blood reaching the
         heart muscle

        Stoke   affects blood reaching the brain

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