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Vertebrate Gas Exchange System
Chapter 11

1)    Distinguish between the processes of: cellular respiration, gas exchange and breathing.

2)    Describe the location, structure and function of the following parts of the respiratory system: pleura, nose, pharynx, epiglottis, larynx, trachea, bronchi, bronchial tubes, bronchioles, air sacs and alveoli.

3)    State the role of the diaphram and ribs during breathing.

4)    How is breathing controlled?

5)    Explain external and internal respiration.

6)    Explain how and why oxygen and carbon dioxide move across alveolar membranes in the lungs and cell membranes in the rest of the body.

7)    Explain how oxygen and carbon dioxide are transported in the blood.

8)    Compare the structure of the respiratory system of a mammal with that of another vertebrate such as a bird.

ANSWERS
1)    Cellular Respiration is the process of breaking down nutrients and releasing energy.

        Gas Exchange is the diffusion of gas on both sides of the respiratory surface.

        Breathing is the expansion contraction of the lungs by forcing air to enter or forcing air to leave.
(page 178-179)

2)  Pleura is the membrane that closely encloses each lung.  This is for structure and support.

    Nose air is taken in and pushed out of the body.  It also warms and cleans (with cillia) air that passes though.  This carries air to the pharynx

    Pharynx is a scientific word for throat.  This is part of the body's defense against infection.  This carries air to the larynx.

    Larynx is commonly known as the voice box.  By vibrating the vocal cords as air is exhaled sounds can be made.  This carries air to the trachea.

    Epiglottis is like a gate that stops food from going into the treachea when swallowing.

    Trachea is the windpipe.  It is kept open by cartilage embedded in its walls.  This carries air to the bronchi.

    Bronchi are the two tubes that the trachea divides into.  These carry air to the lungs bronchial tubes.

    Bronchial tubes are small tubes that branch off in a tree like fashion carring air to the bronchioles.

    Bronchioles are microscopic tubes that are similar to the bronchial tubes except they are much thinner because there is no cartilage.  This takes air to the air sacs.

    Air Sacs is the name that is given to a structure that ressembles a cluster of grapes.  Each air sac holds many alveoli.  (see fig 11-6 page 183)

    Alveoli are one cell thick and act as the respiratory surface.  Each alveoli is surrounded by a rich network of capillaries.  This is where oxygen and carbon dioxide are exchanged from the blood to lungs and vice versa.
(page 183-185)

3)  During inhalation the diaphram is pulled down and the ribs are pulled up and out.  This decreases pressure in the lungs and air rushes in.

    During exhalation the diaphram and intercostal muscles between the ribs relax.  This increases the pressure inside the lungs and air rushes out.
(see fig 11-9 page 186)

4)  Breathing is controlled by the respiratory centre in the brain and many other structures in major arteries that are sensitive to blood oxygen levels.
(page 187)

5)  External respiration is the exchange of oxygen and carbon dioxide between the air and the blood in the lungs.

    Internal respiration is the exchange of oxygen and carbon dioxide between the blood and the body cells.
(page 186)

6)  Oxygen and carbon dioxide move across alveolar and cellular membranes in the body because of the process of diffusion.  Molecules move from an area of high concentration to an area of low concentration.
(page 187-189)

7)  In the blood oxygen is transported by attaching itself to a molecule of hemoglobin.  One hemoglobin can hold four oxygens and is then called oxyhemoglobin.  This turns the blood from a blueish colour to a bright red colour.  Carbon dioxide travels in the blood three different ways.  About 70% travels in the plasmas as bicarbonate ions.  About 20% travels with the hemoglobin as carboxyhemoglobin.  And about 10% travels in the plasma in solution.
(page 189)

8)  The respiratory system of a bird is much more advanced than that of a human.  Since flight requires much more energy than walking, birds must be able to provide their cells with mass quantities of oxygen.  They have air sacs that pouch out from the lungs and occupy space between the internal organs even in the cavities of larger bones.  This provides for more surface area for resperation to take place.
(see fig 35-4 page 621)