- -  AGRICULTURE CORE CURRICULUM  - -

(CLF3000)  Advanced Core Cluster:  ANIMAL SCIENCE

  (CLF3200)  Unit Title:  ANIMAL PHYSIOLOGY

____________________________________________________________________________
  (CLF3203)  Topic:  ENDOCRINE               Time          Year(s) 
                     SYSTEM                 3 hours         3 / 4        
____________________________________________________________________________

          Topic Objectives:  Upon completion of this lesson, the student
                             will be able to:

          Learning Outcome #:

            (C-3)  -  Describe the function of the endocrine system, the
                      location of the glands, and list the hormones that
                      affect growth and reproduction.

          Special Materials and Equipment:  A diagram showing the location
                      of the various endocrine glands.

          References: Cole, H.H. and Ronning, Magnar. (1974). ANIMAL
                        AGRICULTURE.
                    
          Evaluation: Quiz by instructor.


TOPIC PRESENTATION:  ENDOCRINE SYSTEM

    REVIEW Basic Core Curriculum CLF246 AND 247, "Hormone Function and 
    "Hormone Influence".

A.  Endocrine System

    1.  Definition:

        a.  A series of ductless glands located throughout the body that 
            secrete chemicals that control or regulate body functions.

            1)  The ductless glands secrete directly into the blood stream.

            2)  In contrast a duct is like a tube that transports the 
                chemical directly to some organ, like the salivary gland.
                (glands using ducts are known as exocrine glands.)


    2.  Functions:

        a.  Plays a role in regulating an animal's response to changes in 
            its environment.  For example:

            1)  Breeding Seasons - some animals such as sheep breed only 
                during certain times of the year.

            2)  Migratory Habits - seen in wild ducks, geese, and other 
                migratory birds.

        b.  Affects animal behavior, for example:

                Estrous cycles and mating behavior are largely controlled by 
                glands in the endocrine system.

        c.  Regulates many body functions including:

            1)  growth,

            2)  digestion,

            3)  parturition, and

            4)  lactation.

B.  Location of the Glands in the Endocrine System

    1.  The pituitary gland is located in the brain.

        a.  It is also known as the "master gland".

        b.  It controls many other glands in the endocrine system and is 
            directly responsible for producing the following hormones:

            1)  growth hormone - stimulates general body growth.

            2)  luteinizing hormone (LH) - is responsible for androgen
                secretion by the testes and maturation of the follicles in 
                the ovary.

            3)  follicle stimulating hormone (FSH) - controls oogenesis
                and spermatogenesis.

            4)  prolactin - maintains milk production.

            5)  oxytocin - is responsible for milk "let down" and uterine
                contractions.


    2.  The thyroid gland is located in the neck.

        a.  It is responsible for producing:

            1)  calcitonin - controls blood calcium levels.

            2)  thyroxin - controls cell metabolism.  People that are 
                extremely obese may have problems with this gland causing
                slower than normal metabolism.

    3.  The adrenal glands are located on top of each kidney.

        a.  They are responsible for producing:

            1)  glucocorticoids - which mobilize body energy sources and
                have an anti-inflammatory action.

            2)  mineralocorticoids - which control salt and water balance in
                the body.

            3)  epinephrine - which increases the strength of heart 
                contractions and increases blood sugar.

    4.  The pancreas is located near the small intestine.

        a.  It is responsible for producing:

            1)  insulin - which lowers blood sugar levels.

            2)  glucogon - which raises blood sugar levels.

    5.  The kidneys are located in the mid-dorsal region.

        a.  They are responsible for producing:

            1)  renin, and

            2)  angiotensin - both control blood pressure.

    6.  The ovaries are located in the abdominal region in the female.

        a.  They are responsible for producing:

            1)  estrogens - which stimulate and maintain female sex 
                characteristics.

            2)  progesterone - which is required to maintain pregnancy.

            3)  relaxin - which relaxes pelvic cartilages and ligaments for
                parturition.

    7.  The testes are located in the scrotum in the male.

        a.  They are responsible for producing:  testosterone (androgen) - 
            which stimulates and maintains male sex characteristics.


    8.  The digestive tract is located in the abdomen.

        a.  It is responsible for producing:

            1)  secretin, and 

            2)  gastrin - both of which stimulate secretion of digestive 
                juices.


          __________________________________________________________
          ACTIVITY: 
 
          1.  Locate the endocrine glands on a the diagram and 
              disuss the function of each including what other 
              parts of the body are influenced by this particular
              gland.           
          __________________________________________________________


5/2/90sg


#%&C