Module 3S1 Reproductive Systems

2.3.3 page4

Reflect and Connect

Think back to Sam and the semen analysis test he underwent. From your new knowledge of how supporting structures help gametes develop, you can better understand how a semen analysis can contribute to diagnosing an infertility problem.

 

A semen sample must be analyzed within two hours of being collected. Lab technicians analyze the sample for the following traits:

• Volume: Low volume might suggest an anatomical or functional defect.
• Motility: The quality of spermatozoa movement needs to be forward and progressive and 40 to 60 percent of the spermatozoa needs to be motile.
• Count: A count below 20 million/mL could indicate sterility.
• pH: An increase in the sperm's pH above the normal slightly alkaline state could indicate an inflammation of the prostate.
• Fructose: Absence of this sugar may indicate a possible obstruction of the ejaculatory ducts or seminal vesicles.
• Morphology: Size and shape, only 35% or less of the sperm should have some type of abnormal structure, as seen in the image below.

 

Sam’s sperm analysis showed a low sperm count. The medical term for this is oligospermia. If you were Sam’s fertility physician you might have considered prescribing a drug called clomiphene, sold under the name ”Clomid.”

 

Going Beyond

You have been introduced to several disorders in the first three lessons of Module 3. Can you find disorders that are specifically related to the supporting structures like the Sertoli cells, interstitial cells, primary or secondary follicles, and corpus luteum.

 

Module 3: Section 1—Lesson 3 Assignment

Submit your completed Module 3: Section 1—Lesson 3 Assignment to your teacher for assessment.

Lesson Summary

In Lesson 2 you investigated the following focusing questions:

• How do sperm and egg cells develop into functional gametes?
• What supporting structures help in the development of a fully functional gamete?

 

Human reproductive systems are uniquely designed to develop properly functioning gametes thereby ensuring continuation of the human species. In the male reproductive system, the male gonads (the testis) produce the functional gametes (the sperm) in the seminiferous tubules. The Sertoli cells give both structural and secretory support to the developing sperm. Structural support is provided by protecting the developing sperm from the body’s immune system, and secretory support is provided by secreting the hormone inhibin. The interstitial cells, also found in the seminiferous tubules, indirectly support sperm production by secreting the hormone testosterone. Testosterone then stimulates the process of spermatogenesis to develop the sperm.

 

The female gamete, the egg, is produced in the ovary and provided with structural and secretory support. Follicle cells provide structural support by surrounding the primary oocyte helping to nourish, protect, and develop the egg cell. Follicle cells also offer secretory support by releasing estrogen and some progesterone. These hormones then help to develop the primary oocyte into a mature egg ready for ovulation.

Continuation of the species is ensured when these two properly formed gametes are joined through fertilization.

 

Lesson Glossary

oligospermia (also known as oligozoospermia): a condition in which there are less than 20 million spermatozoa per mL of semen