Gas Exchange in Animals

Study Guide 6

 

          Describe the general requirements for a respiratory surface and list the variety of respiratory organs that have adapted to meet them.

            A respiratory surface must have large surface area and must be moist, e.g., gills, tracheal system of insects, and lungs.

 

          Describe respiratory adaptations of aquatic animals.

            Countercurrent exchange to increase O2 uptake by the blood and ventilation to exchange water around gills,  

     

          Describe the advantages and disadvantages of water as a respiratory medium.

            Advantages are maintains moist respiratory surfaces, disadvantages are the low concentration of O2 in water, the diffusion rate is slower in water than air requiring that the surface be ventilated continually.

 

          In the human respiratory system, describe the movement of air through air passageways to the alveolus, listing the structures that air must pass through on its journey.

            Air moves into the lungs by negative pressure and is exhaled by relaxation of the rig cage and diaphragm restoring the thoracic cavity to its smaller volume.  Larynx>trachea >bronchi>bronchioles>alveoli>capillaries

 

Explain how the respiratory system of birds is different from that in mammals.

            Birds have 8 or 9 air sacs which act like bellows that keep air flowing through the lungs.  The sites of gas exchange is in tiny channels called parabronchi.  Birds completely exchange air in lungs with every breath making for very efficient gas exchange.  This in part allows birds to fly at very high altitudes.

 

          Describe the adaptive advantage of respiratory pigments in circulatory systems. Distinguish between hemocyanin and hemoglobin.

            Respiratory pigments increase the amount of O2 or CO2  that can be carried by blood.  Hemocyanin binds O2 to a copper molecule and hemoglobin uses iron to bind 4 molecules of O2

     

          Describe respiratory adaptations of diving mammals and the role of myoglobin.

            Diving mammals are able to store O2 in the blood and also in the spleen, they have high concentration of oxygen-storing protein (myoglobin) in muscles, and they conserve O2 by using decreased muscular effort.