Chapter 22: The Reproductive Systems

Chapter Synopsis

This chapter discusses the essential and accessory organs of the male and female reproductive systems. It also describes the generalized functions that each of these organs perform. Testosterone is the major male hormone, and estrogen and progesterone are the major female hormones. The essential functions that these hormones perform in the body are presented along with the description of the cell types involved in their production. Disorders of the male and female reproductive systems are listed and explained.

Chapter Objectives and Notes

1.      List the essential and accessory organs of the male and female reproductive systems and give the generalized function of each.

a.       Essential organs of the male reproductive system

i.         Testes—produce sperm cells

b.      Accessory organs of the male reproductive system

i.               Epididymis—stores sperm cells

ii.             Vas deferens—receives sperm from epididymis

iii.            Ejaculatory duct—receives sperm from vas deferens

iv.           Urethra—passes sperm to exterior

v.             Seminal vesicles—produce alkaline secretions

vi.           Cowper’s glands—produce alkaline secretions

vii.          Prostate—produces alkaline secretions

viii.        Scrotum—contains testes

ix.           Penis—enters the vagina and deposits sperm during intercourse

c.       Essential organs of the female reproductive system

i.         Ovaries—produce egg cells

d.      Accessory organs of the female reproductive system

i.         Uterine tubes—fertilization occurs here; if there is no fertilization, the egg will disintegrate here

ii.       Uterus—holds the baby during pregnancy, sheds its lining if pregnancy does not occur and contracts during labor

iii.      Vagina—the organ through which sperm enter the female body and the organ from which the baby emerges

iv.     Bartholin’s glands—secrete mucus-like lubricating fluid

v.       Breasts—function during lactation

vi.     External genitals—function to protect

2.      Describe the gross and microscopic structure of the gonads in both sexes and explain the developmental steps in spermatogenesis and oogenesis.

            The testes are small oval-shaped glands about 11⁄2 inches long and 1 inch wide. They are slightly flattened and egg-shaped. Each is surrounded by a tough whitish membrane called the tunica albuginea. This membrane covers the testicle and then enters the gland to form many septa that divide it into lobules. Each lobule consists of a narrow, long, coiled tube called the seminiferous tubule. Small clusters of interstitial cells lie near the septa that separate the lobules.

            If a thin section of tissue is cut from the testicle and viewed under a microscope, individual seminiferous tubules and clusters of interstitial cells can be seen. Each tubule is a ductlike structure with a central lumen. Sperm cells develop in the walls of the tubule and are then released into the lumen and begin their journey to the exterior of the body.

            Ovaries lie within the pelvic cavity. The ovarian ducts open into the abdominal cavity; they do not attach directly to the ovaries. Several thousand sacs called ovarian follicles make up the bulk of each ovary. Within each follicle lies an immature ovum. This ovum in its sac is called a Graafian follicle. The youngest of these follicles are located in what is called the egg nest. The majority of the whole follicle is composed of hormone-secreting granulosa or follicular cells. The hormone estrogen is secreted by these cells. At the time of ovulation the maturing ovum is the body’s largest cell. It is surrounded by a shell called the zona pellucida.

3.      Discuss the primary functions of the sex hormones and identify the cell type or structure responsible for their secretion.

a.       Testosterone serves the following general functions:

i.         Masculinizes

ii.       Promotes and maintains the development of male accessory organs

iii.      Has a stimulating effect on protein anabolism

b.      Testosterone is produced by the interstitial cells of the testes.

c.       Estrogen and progesterone serve the following functions:

i.         Cause the development of the female secondary sex characteristics

ii.       Stimulates the growth of the reproductive organs, the external genitals, pubic hair, and breast development.

iii.      Deposits fat

iv.     Initiates menstruation

d.      Estrogen and progesterone are produced by granulosa cells and corpus luteum.

4.      Identify and discuss the phases of the endometrial or menstrual cycle and correlate each phase with its occurrence in a typical 28-day cycle.

       A typical menstrual cycle covers a period of 28 days. Each cycle consists of three phases. In the first phase called the menstrual period or menses (about the first 4 or 5 days) there is sloughing of bits of endometrium accompanied by bleeding. In the postmenstrual phase (days between the end of menses and ovulation) the endometrium is being repaired. In the premenstrual phase (days between ovulation and the beginning of the next menses) there is further thickening of the endometrium and secretion by its glands in preparation for implantation of the fertilized egg.

5.      List the major disorders of the male and female reproductive systems and briefly describe each.

a.             Disorders of the male reproductive system may cause infertility or sterility. They include:

                                    Oligospermia—low sperm count

                                    Cryptorchidismundescended testes

                                    Testicular cancer—malignant neoplasm,most common in young adult men aged 25–35

                                    Orchitis—infection of the testis

                                    Epididymitis—infection of the epididymis

                                    Benign prostatic hypertrophy—enlargement of prostate gland

                                    Phimosis—tight foreskin

                                    Impotence—failure to achieve an erection of the penis

                                    Hydrocele—accumulation of watery fluid in the scrotum

                                    Inguinal hernia—protrusion of abdominopelvic organs, possibly into                                         the scrotum

b.            Disorders of the female reproductive system

                                    Dysmenorrhea—painful menstruation

                                    Amenorrhea—absence of normal menstruation

                                    Dysfunctional uterine bleeding (DUB) irregular or excessive bleeding resulting from a hormonal imbalance Premenstrual syndrome (PMS)—collection of physiological changes that occur prior to menstruation

                                                                           i.      Infection and inflammation

                              Exogenous—sexually transmitted and caused by organisms already in or on the body Pelvic inflammatory disease (PID)—acute inflammatory condition of the uterus, tubes, or ovaries caused by infection

                                          Toxic shock syndrome (TSS)—infection of the blood causing septic shock

                                          Myoma—fibroids, benign tumors of the uterus

                                          Ovarian cysts—fluid-filled enlargements;usually benign

                              Endometriosis—presence of functioning endometrial tissue outside the uterus Breast cancer—most common type of cancer in women

                              Ovarian cancer—can result from metastasis of breast cancer or can arise inde-pendently

6.            Define the term sexually transmitted diseases and describe the major types.

STDs are transmitted by sexual contact but can also be transmitted in other ways. They are infections caused by communicable pathogens such as viruses, bacteria, fungi, and protozoans.

AIDS—a viral condition that can be spread through sexual contact or trans-fusion of infected blood and use of contaminated medical instruments Candidiasis—a yeast infection characterized by a white discharge, peeling skin, and bleeding

Genital herpes—caused by virus and causes blisters on skin of genitals

                  Genital wartsnipplelike neoplasms of skin covering genitals

Gonorrhea—primarily involves genitals and urinary tract; may progress to pelvic inflammatory disease

Hepatitis—acute-onset liver inflammation that may develop into a severe          chronic disease, perhaps ending in death

Lymphogranuloma—chronic STD char-acterized by genital ulcers, swollen lymph nodes, headache, fever, and muscle pain

Scabies—infestation by the itch mite, which burrows into the skin to lay eggs

Syphilis—affects any system, characterized by chancre sores on exposed areas of the skin

Chapter 22 Review

Short Answer

Complete the following objectives. Write your answers on a separate sheet of paper.

1.                                                                                          List the essential and accessory organs of the male and female reproductive systems and give the generalized function of each.

2.                                                                                          Describe the gross and microscopic structure of the gonads in both sexes, and explain the developmental steps in spermatogenesis and oogenesis.

3.                                                                                          Discuss the primary functions of the sex hormones, and identify the cell type or structure responsible for their secretion.

4.                                                                                          Identify and describe the structures that constitute the external genitals in both sexes.

5.                                                                                          Identify and discuss the phases of the endometrial, or menstrual, cycle and correlate each phase with its occurrence in a typical 28-day cycle.

 Fill in the Blank

6.                                                                                          In reviewing the following vocabulary words, decide which words relate to the female, which to the male, and which to both sexes. After each word write (F) for female, (M) for male, or (B) for both:

menses             seminiferous tubule                    fimbriae                        gonads                                     progesterone

ovulation                       ejaculation                                genitals             perineium                                  endometrium

epididymis                    Graafian follicle             scrotum                        episiotomy                                meiosis

areola                           testes                                        menopause                   circumcision                              testosterone

spermatogenesis           estrogen                                   clitoris                          vulva                                        spermatozoa

semen

7.                                                                                          List the analogous features of the female and the male reproductive systems:

Feature                                               Female                                                Male

Essential organs                      

Sex cells                     

Hormones                  

Hormone-producing cells                    

Duct system                

External genitals                      

8.                                                                                          During a 28-day menstrual cycle, at what point in the month might the postmenstrual phase take place?

(A)  days. Ovulation?

(B)  days. Premenstrual phase?

(C)  days. Menstrual Period?

(D)  days.