Fetal Pig Dissection PURPOSE In

Document Sample
Fetal Pig Dissection PURPOSE In Powered By Docstoc
					Fetal Pig Dissection
PURPOSE
In this lab, you will study the external and
internal anatomy of a fetal pig, relate its
structures to those of other mammals, and
determine differences between a fetal pig and
an adult pig.

PART 1—EXTERNAL ANATOMY
   a. Put on safety goggles and gloves.

   b. If necessary, turn the specimen in the
      dissecting tray, as shown in the
      diagram. Use this diagram to help you
      locate and identify the external
      features of the fetal pig, including the
      head, neck, trunk, and tail regions.

   c. Measure and record the length of your specimen. Determine the age of your fetal pig using this table:




   d. Turn the animal ventral side up as shown in the diagram below. Locate the teats (nipples of the mammary
      glands) and the umbilical cord. Using scissors cut the umbilical cord near where it joins the abdominal wall. In
      the umbilical cord, locate the two umbilical arteries and the one umbilical vein.
    e. Try to locate the scrotal sac between the hind legs. The sac may or may not contain the fully descended testes.
       The presence or absence of the scrotal sac can be used to determine the sex of your specimen.
    f. Locate the urogenital opening. In the male, the opening releases both sperm and urine from the body. In the
       female, the urogenital opening is located immediately ventral to the anus, the external opening of the rectum.
       The anus is ventral to the tail. Lift the tail to locate the anus.

QUESTIONS:
    If your pig is male:
    1. How old is your fetal pig?
    2. Describe the structure and function of the umbilical cord.
    3. What are the names of the gonads in the male?
    4. How and when are sperm made?
    5. What are the male sex hormones and where are they made?
    6. Why is the scrotum on the outside of the body?
    7. What is the purpose of the epididymis?
    8. What is the purpose of the prostate?

    If your pig is female:
    1. How old is your fetal pig?
    2. Describe the structure and function of the umbilical cord.
    3. What are the names of the gonads in the female?
    4. How and when are eggs made?
    5. How many ova are released during ovulation?
    6. What are the female sex hormones and where are they made?
    7. What transports the egg from the ovary to the uterus?
    8. What is the location of fetal implantation in the pig?


You will not be able to complete the dissection in one lab period. Shortly before the end of the period, your teacher will
have you stop your dissection. Store the specimen in a plastic bag, close it with a twist tie, and use a felt-tip marking pen
to write your name on the bag. Clean up your work area and wash your hands before leaving the lab.
ANSWERS


  If your pig is male:
  1. How old is your fetal pig?                                If your pig is female:
       Answers will vary                                       1. How old is your fetal pig?
                                                                    Answers will vary
  2.   Describe the structure and function of the umbilical
       cord.                                                   2.   Describe the structure and function of the umbilical
        Connects fetus to placenta                                 cord.
        The umbilical vein supplies the fetus with                  Connects fetus to placenta
           oxygenated, nutrient-rich blood                           The umbilical vein supplies the fetus with
        The umbilical arteries return the deoxygenated,                oxygenated, nutrient-rich blood
           nutrient-depleted blood                                   The umbilical arteries return the deoxygenated,
                                                                        nutrient-depleted blood
  3.   What are the names of the gonads in the male?
       Testes                                                  3.   What are the names of the gonads in the female?
                                                                    Ovary
  4.   How and when are sperm made?
       Post puberty onward                                     4.   How and when are eggs made?
       Seminiferous tubule of testes                                Ovary
       Meiosis I triggered by FSH                                   FSH stimulates follicle to mature
       Meiosis II triggered by testosterone                         Ovulation monthly
       Differentiation
                                                               5.   How many ova are released during ovulation?
  5.   What are the male sex hormones and where are                 8-14
       they made?
       FSH – pituitary                                         6.   What are the female sex hormones and where are
       LH – pituitary                                               they made?
       Testosterone – Leydig cells                                  FSH – pituitary
                                                                    LH – pituitary
  6.   Why is the scrotum on the outside of the body?               Estrogen – follicle
       Temperature regulation                                       Progesterone – corpus luteum

  7.   What is the purpose of the epididymis?                  7.   What transports the egg from the ovary to the
       Maturation of spermatozoa                                    uterus?
                                                                    Fallopian tube / oviduct
  8.   What is the purpose of the prostate?
       Secretes an alkaline solution, neutralizes acids from   8.   What is the location of fetal implantation in the pig?
       urine and vaginal wall                                       Uterus

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:76
posted:9/17/2011
language:English
pages:3