Embryology Tutor

Genital System Lesson

© 1997
by
Thomas F. Fletcher, DVM, PhD
Department of Veterinary Biology
University of Minnesota
St.Paul MN 55108

Contents:
         Lesson Objectives
         Lesson Content Outline
         Student Evaluations
         Platform requirements
         Download instructions

Lesson Objectives:

• Understand the concept of a developmental indifferent stage (common embryonic features found in both sexes).
• State the embryonic origin of the germ cells and supporting cells that comprise the gonad.
• Describe how cellular organization differs in testis development vs ovary development.
• Contrast spermatogonia and oogonia meiosis in the testis and ovary.
• Describe the embryonic development of male and female internal genitalia, including associated ligaments and glands.
• Describe the role of the gubernaculum in descent of the testis.
• List indifferent-stage components that give rise to external genitalia and describe the fate of each component in the male and in the female.
• Explain all of the events involved in formation of the penis and prepuce.
• Describe mammary gland development.

Detailed Outline of Lesson Content:

I. Urogenital ridge (derived from intermediate mesoderm)
A. Origin of intermediate mesoderm

II. Gonad (derived from gonadal ridge component of the urogenital ridge)
A. Indifferent stage (parenchyma = germ cells & supporting cells)
1] primordial germ cells (migrate from yolk sac)
2] supporting cells (derived from mesonephric tubules & coelomic mesothelium)
B. Testis (formation of seminiferous tubules)
1] spermatogonia (germ cells)
2] Sertoli & interstitial cells (supporting cells)
C. Ovary (formation of primordial follicles)
1] oogonia & primary oocytes (germ cells)
2] follicle cells (supporting cells)

III. Internal genitalia
A. Indifferent stage
1] mesonephric & paramesonephric ducts
2] urogenital sinus
B. Female (paramesonephric duct)
1] uterine tube, uterus, vagina
2] broad & associated ligaments
C. Male (mesonephric duct))
1] epididymus & ductus deferens
2] accessory genital glands
3] gubernaculum & testicular descent

IV. External genitalia
A. Indifferent stage
1] genital tubercle
2] urogenital folds
3] scrotal folds
B. Female
1] clitoris
2] vulva & vestibule
C. Male
1] penis
2] prepuce
3] scrotum
D. Mammary glands

V. Clinical anomalies

Student Evaluations:

Platform Requirements:

      Embryology Tutor 0.9.8 is a HyperCard stand-alone application. Minimal requirements are a Macintosh computer with a 9-in. black & white screen and 2 MB of RAM available to run the application. Disc size is 4.5 MB (including all lessons).

Download Instructions:

      A Macintosh computer is required to run Embryology Tutor 0.9.8. When you click "Download Now" (below), a 2.2 MB compressed, self-extracting, binary file "Embryology Tutor 0.9.8.sea" will be transmitted to the location on your hard disk where your browser downloads files. Double-click the downloaded file icon to extract a 4.3 MB folder "Embryology Tutor 0.9.8" (your browser may extract this file automatically). Inside the folder, double-click the HyperCard application entitled "Begin Embryology Tutor" to view the courseware (the application and lessons frolder must remain in the same parent folder). You can trash "Embryology Tutor 0.9.8.sea" to conserve disk space.) Download Now