Module 3 Lesson 2 - 4 (Lab)

Lab - Examining Gonads and Gametes

Introduction

Although the testes and ovaries are different structures, they serve the same two basic functions:

• development of gametes

• secretion of sex hormones

In this investigation, you will compare ovarian and testicular tissues using microscopy images provided (scientific term for objects viewed by a microscope). This will assist you to identify the supporting structures that help develop the egg and sperm cells.

This lab is similar to that on page 483 of the textbook. However, because you may not have a microscope, the microscope slides will be provided to you. The procedure has been rewritten to guide you through the lab using the microscopy images.

This lab is a continuation from the previous lesson. In this lesson, you will complete Part 2: Ovarian Tissue. Complete the drawings when instructed to do so as you progress through this lab.

Problem

How do the structures of testicular and ovarian tissues relate to their biological functions?

Materials

• blank paper
  
• pencil
  
• microscopy images of cat follicle, 100X, 200X, 400X (provided below)

Procedure

Part 2 — Ovarian Tissue

1. Examine the microscopy images provided below. Pay attention to the magnification power given.  Look for larger circular structures; these are developing egg cells. Try to identify the following structures in the images: primary follicle, oocyte, mature follicle, mature ovum, ovarian tissue, and corpus luteum.
   

The source of the microscopy images is http://www.new.learnalberta.ca. The use of these materials is done without any affiliation with or endorsement by the Government of Alberta

• Primary Follicle 100X
  
• Primary Follicle 200X
  
• Mature Follicle 100X
  
• Mature Follicle 400X
  

Microscope image of a cross-section of a cat ovary showing a primary follicle at 100X magnification 



The source of the materials is http://www.new.learnalberta.ca. The use of these materials is done without any affiliation with or endorsement by the Government of Alberta
 
 


Microscope image of a cross-section of a cat ovary showing a primary follicle at 200X magnification






Microscope image of a cross-section of a cat ovary showing a mature follicle at a 100X magnification



 



Microscope image of a cross-section of a cat ovary showing a mature follicle at a 400X magnification



 




2. Draw a diagram of the specimen images, Primary Follicle at 100X and Mature Follicle at 100X. Label the following structures in your drawing primary follicle, ovarian tissue, oocyte, corpus luteum, mature follicle, and mature ovum. Save your drawing for future study.

Check Your Work.

Observations

After examining the microscopy slides of testicular and ovarian tissues, you should have completed three diagrams with appropriate labels and titles. You should now be able to identify the functional gametes as well as their supporting structures.

Conclusions

In this lab, you identified the location and function of the gonads, gametes, and their supporting structures. Reproduction, and therefore continuation of the species, would be impossible if not for proper functioning of the supporting cells that develop the gametes.

Self-Check

1. What are the two main purposes of the gonads in both males and females?
   


2.  Write a short description of each of the following, summarizing its function.
   1. fimbriae
   2. endometrium
   
   
3. Which structures contribute to the movement of the ovum from the ovary to the uterus?
   


4. Describe briefly the structure of an ovum. How does the structure of the cell relate to its function?