Power Point Ch 42 - Slide 1

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Power Point Ch 42 - Slide 1 Powered By Docstoc
					         Transport systems
• Vessels/tubes
• Contain a circulatory fluid ( blood or
• Found in larger animals where
  diffusion alone is inadequate to supply
  gas exchange or carry nutrients
Thin jellyfish also have a transport system
 Gastrovascular cavity circulates water and digested food
    Open vs. closed circulatory
• Open - “blood” is called hemolymph.
  It flows in vessels that empty into
  open spaces called sinusus; heart is
  present. Blood bathes cells
• Closed – blood never leaves the
  vessels; blood is pumped by heart;
  molecules diffuse through vessel
           Open circulatory system

Tracheal tubes of
respiratory system
connect with
holes in exoskeleton
 to bring oxygen into           Body cells

the body and transfer
oxygen to the body
cells and
Closed circulatory system

            A higher pressure system
            needed in larger animals
        Generalized circulation -   FISH

2 chambered heart
   1 atrium, 1 ventricle
   one circulatory loop
   low pressure to the body
Amphibian Heart

            3 chambered heart
              2 atria, 1 ventricle

            2 circulatory loops
            Blood to body under
                high pressure
            Partial mixing of CO2
               and O2 blood in heart
    Mammal / Bird/
    reptile heart
4 complete chambers
  2 atria, 2 ventricles

No mixing of CO2 and O2 blood

2 circulatory loops ( circuits )
High pressure to lungs and body
Figure 42.4 The mammalian cardiovascular system: an overview
Figure 42.5 The mammalian / bird heart: a closer look

• One cell thick – endothelial cells
• Are permeable
• Site of exchange between blood and
  Interstitial fluid which supplies body cells
• Every organ has a capillary bed
Blood flow in capillary beds

              Flow to organs is
              controlled ( by sphincters )
              and based on need.

              Brain and kidneys have
              continuous blood flow.
          Veins vs Arteries

• Arteries – thicker walled, have more
 smooth muscle, more elastic fibers……
 help maintain blood pressure; carry blood
 from heart… blood usually oxygenated

• Veins – have valves to prevent back flow;
thinner walled, return blood to heart under
Low pressure, blood usually unoxygenated
Figure 42.8 The structure of blood vessels
Blood flow in veins

          Helps push blood along
Measurement of blood pressure
Sphygmomanometer stops blood
   Pressure in cuff is released
  and nurse listens for thumping

Make mental note of pressure when thumping
Make mental note when thumping
        stops 110/65
          Control of the heart
• SA node/ pacemaker in wall of right atrium
  – sends electrical signals across heart
• AV node delays signal to allow ventricles
  to stay relaxed and fill
     Blood pressure numbers

• Top number = pressure of blood when
  Ventricles have contracted
  (systolic pressure ) eg 110

• Lower number = pressure of blood when
  ventricles are filling ( diastolic ) eg 65
    110/65 mm Hg
Capillaries – the sites of exchange

• Diffusion – small molecules ( O2, CO2,
  water, amino acids, sugar, ions ) diffuse
  along their gradients in and out of
  capillaries to and from the extracellular
• Osmosis – non diffusible plasma proteins
lower the water potential and cause water to
  re enter the capillaries
The movement of fluid between capillaries and the interstitial
                          fluid        Water re-enters caps
                                       by osmosis; blood
  Bulk flow squeezes                   proteins lower water
  Water and solutes out of caps        potential in caps
                                                    Net pressure
                                                    inside is negative
                                                    causing fluid to
                                                    re-enter caps
Pluripotent bone marrow stem cells
                          Location of active bone marrow
• A patient can receive
  an autologous (self)
  bone marrow
  transplant of his/her
  own stem cells.
• Marrow stem cells
  from related donors
  can also be given to
Lymphatic vessels return excess extracellular fluid to the circulatory system
rbc, wbc and platelets form in marrow ;
    wbc’s also form in lymph nodes
Normal   Blood smear


                            Hemoglobin – 4 chains, quaternary

                            A single base substitution causes
                            sickle cell anemia…… a recessive

Hbg also carries NO, nitrous oxide which relaxes capillary walls
Dissociation curves for two hemoglobins

                               Fetal hemoglobin binds with
                               oxygen at lower partial
                               O2 pressures than adult
                               hemoglobin. This ensures
                               fetal blood is fully oxygenated
Figure 42.28 Oxygen dissociation curves for hemoglobin
Figure 42.29 Carbon dioxide transport in the blood

                                Bicarnonate ion HCO3- travels in
                                Plasma back to lungs
Figure 42.16a   Blood clotting – initiated by platelets

           Cut capillary

            Platelets start a clot by releasing
            Clotting factors….. Eventually
            Fibers of fibrin criss cross the    cut
                 Figure 42.16x Blood clot

Fibrin network
 and trapped
    Figure 42.17 Atherosclerosis: normal artery and artery with plaque.
       Plaque reduces space inside artery = raises blood pressure;
Rough deposits inside can trigger blood clotting. A blood clot that travels to
    the cardiac arteries can aause a heart attack; to the brain, a stroke

Figure 42.18 The role of gas exchange in bioenergetics
    Respiratory surfaces must be:

•   Thin
•   Moist
•   Large ( may be folded )
•   near blood or hemolymph
                gills of a salmon

thin, folded,
Figure 42.20 The structure and function of fish gills
   Counter current flow of blood and water increases
   gas exchange between blood and water
Counter Current Exchange
  vs same currentl flow
Figure 42.19 Diversity in the structure of gills, external body surfaces functioning in
                                   gas exchange
Figure 42.22   Tracheal system in insects
The mammalian respiratory system
                    mouse lung

Spongy, thin walled alveoli, bronchiole
Thin walled, single cell thick, wrapped in capillaries - alveoli
Figure 42.24 Negative pressure breathing
Figure 42.26 Automatic control of breathing

                                    CO2 in blood lowers the pH
                                    Medulla detects lower pH
                                    and increases the depth
                                    and rate of breathing.

                                     CO2 + H20 = carbonic acid

                                    Carotid arteries have oxygen
                                    receptors that depress
                                    breathing when oxygen is high
Figure 42.27 Loading and unloading of respiratory gases
Figure 42.25 The avian respiratory system – two breaths for one breathing
cycle; lung is always filled with fresh air. Air sacs help keep lung supplied
           with oxygenated air; needed for high metabolic rate
Figure 42.30 The Weddell seal, a deep-diving mammal and other sea mammals
    have myoglobin and other special adaptations to limit and control oxygen
   consumption = long term responses to changes in environment = evolution
                                                 Get ATP by fermentation
                                                 Lower heart rate
                                                 Blood routed to brain, eyes
                                                 Reduced blood flow to
                                                  muscles = short term responses
                                                 to environmental change

                                                 Pg 896

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