- -  AGRICULTURE CORE CURRICULUM  - -

(CLF3000)  Advanced Core Cluster:  ANIMAL SCIENCE

  (CLF3200)  Unit Title:  ANIMAL PHYSIOLOGY

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  (CLF3202)  Topic:  RESPIRATION             Time           Year(s) 
                                            1 hour           3 / 4        
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          Topic Objectives:  Upon completion of this lesson, the student
                             will be able to:

          Learning Outcome #:

            (C-2)  -  Briefly explain the process of respiration, utilizing
                      a diagram of the lungs.

          Special Materials and Equipment:  A diagram of the lungs (see 
                      references), or bring in the lungs and heart of a lamb
                      or hog from a slaughter house.

          References: California Vocational Agriculture Guidelines, AG 
                        PRODUCTION, "Anatomy and Physiology of Farm Animals".

          Evaluation: Quiz by instructor.


TOPIC PRESENTATION:  RESPIRATION

A.  The Respiratory System

    1.  Its basic function is to enable body cells to be supplied with 
        oxygen and rid the body of carbon dioxide.

    2.  Basic parts and their function:

        a.  Nasal Cavity -

            1)  contains cylindrical passages enclosed by facial bones.

            2)  contains thin bony plates in each nostril which are covered 
                with a mucous membrane and with many blood vessels.

            3)  traps dust and foreign particles.

            4)  raises the temperature of cold air before it enters the 
                lungs.

        b.  Pharnyx -

            1)  is the common passage for air and food.

        c.  Trachea - is a cartilaginous tube that connects the pharynx to 
            the lungs.

        d.  Bronchi - 

            1)  are the end sections of the trachea that join the lungs.

            2)  are divided into many tiny tubes which penetrate into all 
                parts of the lungs.

            3)  have at the end of each tiny tube, clusters of minute air
                sacs called alveoli, where oxygen in the lungs is exchanged
                with carbon dioxide in the blood.

        e.  Lungs - are the principle organs of respiration which consist of
            2 elastic membranous sacs containing bronchi and alveoli.

            1)  the bronchi are the larger passage ways leading to the
                alveoli.

            2)  The alveoli are tiny sacs where reoxygenation of the blood
                actually takes place which is the exchange of carbon dioxide
                for oxygen.

        f.  Pleura - is composed of 2 membranes that enclose the pleural 
            cavity (lungs) and contains a fluid between these membranes.

        g.  Diaphragm - 

            1)  is a muscle that separates the thoracic cavity from the
                abdominal cavity.

            2)  aids in breathing by creating a negative pressure in the 
                thorax (chest) when it contracts, allowing air to rush in 
                and fill the lungs.

B.  The Respiration Process

    1.  There are 2 processes involved:

        a.  Inspiration (inhale) -

            1)  air flows into the lungs,

            2)  the trachea and nostrils open up,

            3)  the rib muscles expand (relax) and the diaphragm contracts,
                and

            4)  the thoracic cavity enlarges and air rushes in.


        b.  Exhalation (exhale) - 

            1)  air flows out of the lungs,

            2)  relaxation occurs in the trachea and nostrils,

            3)  the rib muscles contract, and

            4)  the size of the thoracic cavity decreases, and air
                flows out.

C.  Regulation of respiration

    1.  Controlled by the respiratory center in the brain.

    2.  Respiration rate is affected by:

        a.  excitement,

        b.  temperature,

        c.  exercise, 

        d.  fever or pain, and

        e.  oxygen levels in the blood (and brain).

    3.  Below is a list of normal respiratory rates for various 
        animals:

       ============================================================
        Animal                    Normal Respiration Rate
       ____________________________________________________________

        Cattle                    10 - 30 breaths per minute

        Sheep                     12 - 20

        Swine                      8 - 13

        Horses                     8 - 16

        Poultry                   15 - 36
       =============================================================

          __________________________________________________________
          ACTIVITY: 
 
          1.  Trace the pathway of air through the lungs using a 
              diagram.

          2.  Examine lungs and heart from a lamb or pig and find the
              parts discussed in lecture.            
          __________________________________________________________

4/16/90 sg/gv


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