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Human Reproduction

The Male Reproductive System

Instructions: Read the paragraphs below and the descriptions. Use the reading to help you label the diagram and answer the questions.

 

 The purpose of the male reproductive system is to produce sperm cells and to transfer them to the female reproductive system. This will teach you about the structure and function of the male reproductive system.

Statements

1.       Sperm are made in two structures called testes. Each testis is about  4 cm long and about 2.5 cm wide. Since body temperature is 37C is too hot for the maturation and the survival of sperm cells, the testes are located outside the body cavity in a sac called the scrotum. Arrow A points to the testes and arrow B points to the scrotum.  Mark them on the diagram.

2.       Muscular contractions propel newly formed sperm from the testis.  It contains a coiled tube about  600cm long.  Within this tube, newly formed sperm cells reach maturity; the sperm’s head and acrosome change shape slightly, and the sperm loses cytoplasm and becomes  somewhat smaller.  The sperm also acquires the ability to swim.  Arrow C points to the epididymis.  Locate arrow C and label it “epididymis.”

3.       Mature sperm cells leave the epididymis and pass into the vas deferens for storage.  The vas deferens is a tube about 30cm long.  Arrow D points to the vas deferens.  Locate arrow D and label it “vas deferens.”

4.       The term ejaculate means “to discharge suddenly.”  When ejaculation occurs during sexual contact, the walls of the vas deferens contract rapidly, propelling the sperm cells from the body.  Scientists have estimated that the speed at which sperm leave the body is about 6 meters  per second.

Before leaving the body, the sperm cells pass three glands that secrete liquid substances.  These substances, when mixed with sperm, are collectively called “semen.”  The functions of these glands are as follows:

a.        The prostate gland, which is about 4 cm long, lies just below the bladder.  During ejaculation, this gland adds a milky fluid to the sperm.  Scientists  think  that this fluid contains substances that somehow activate the sperm and cause them to wave their flagella.  Arrow E points to the prostate gland.  Locate arrow E and label it “prostate gland.”

b.      Attached to the back wall of the bladder are two seminal vesicles about 6 cm long.  Through a tube called the “ejaculatory duct,” the seminal vesicles add a mucus like fluid to the sperm.  This fluid contains the monosaccharide (simple sugar) fructose.  Arrow F points to the seminal vesicles.  Locate arrow F and label it “seminal vesicles.”

c.       Two pea-sized glands called “Cowper’s glands” release a mucus like lubricant substance.  Arrow G points to the Cowper’s glands.  Locate arrow G and label it “Cowper’s glands.”

5.        After the sperm have combined with the seminal fluid, they leave the body through a tube called the “urethra.”  The urethra passes through the penis.  The function of the penis is to transfer seminal fluid to the female reproductive system.  Arrow H points to the penis, and arrow I points to the urethra.  Locate these arrows and label them.

6.       The penis contains three cylindrical structures made of a spongy tissue called “cavernous tissue.”  When cavernous tissue fills with blood, it makes the penis stiff.  This stiffness, which is called an “erection,” makes it possible for the penis to enter the female reproductive system.  Arrow J points to the cavernous tissue.  Locate arrow J and label it “cavernous tissue.”

Level One Questions:

1.        Sperm are made in two oval structures called                                                                                    .

2.       The testes are located in a saclike structure called the                                                                    .

3.       The epididymis is a coiled tube about                                                                                                     .

4.       The vas deferens is a                                       about                                                    centimetres long.

5.       The term ejaculate means to                                                                                       suddenly.

6.       Sperm leave the body at a speed of about                                                            meters  per second.

Level Two Questions:

7.        Why are the testes located outside the body cavity?                                                                                     

8.       Where does final maturation of a sperm cell occur?                                                                                        

9.       What three things occur during final maturation?                                                                                             

 

 

 

10.   Where are sperm stored after they leave the epididymis?                                                          

 

 

11.   What is semen?                                                                                                                                                                                                                                                                                                                                                               

 

12.   Describe the function of each of the following:

a.       Prostate gland                                                                                                                                                                                                                                                                                                                                                  

b.       Seminal vesicles                                                                                                                                                                                                                                                                                                                                             

c.       Cowper’s glands                                                                                                                                                                                                                                                                                                                                              

13.    Describe the structure and function of cavernous tissue.

                                                                                                                                                                                               

                                                                                                                                                                                               

                                                                                                                                                                                               

 

Level Three Questions:

14.    Arrange the following terms in the order in which semen travels as it leaves the testes to be ejaculated from the body.  Next to each term in your list, describe its function.

        vas deferens             urethra                      testes                     epididymis

  

 
 
 
 
 
 
 
The Female Reproductive System
 

Instructions:  1.  Read the descriptions.  2.  Use the text and the descriptions to help you to answer the questions.

The main structures of the female reproductive system are the vagina, the uterus, the Fallopian tubes, and the ovaries.  These organs are responsible for the maturation of ova (eggs), for facilitating fertilization, and for providing a suitable environment for the growth and development of the embryo.

This will help you to learn about the structures and functions of the female reproductive system.

 

Statements:

1.       The vagina is a muscular tube that begins at the opening of the female reproductive tract.  It extends upward and behind the bladder where it is connected to the uterus.  Male gametes (sperm) are introduced into the female reproductive system through this tube.  During childbirth, this flexible tube widens and serves as the birth canal.  Arrow A points to the vagina.  Locate arrow A and label it “vagina.”

2.       The ovaries are two almond-shaped structures about 3.5cm in length .  When she is born, a female has about 400,000 primary oocytes (immature eggs) stored in her ovaries.  Arrow B points to the left ovary.  Locate arrow B and label it “ovary.”

3.       The primary oocytes remain relatively dormant until the female reaches puberty (sexual maturity) and the menstrual cycle beings.  During the monthly menstrual cycle, changes occur within the female reproductive system.  These changes provide mature ova (eggs) and prepare the uterus for pregnancy.

At the beginning of each menstrual cycle, several primary follicles containing immature ova or eggs are stimulated, but usually only one ovum reaches maturity.  This ripened ovum is contained in a transparent vesicle called a “Graafian follicle.”

Beginning with the primary follicle, the following steps describe the formation of the Graafian follicle.  Arrow C points to a cross-section of the ovary.  This ovary has been lowered and slightly enlarged to show the developing follicles inside.  Identify and sketch the structures as they are described here.

A:  Before every female is born, her primary follicles are already formed.  Each primary follicle           contains an oocyte surrounded by a ring of granulose cells.  Arrow D points to a primary follicle.  Locate this arrow and use it to help you to sketch (in the space here) a primary follicle.

 

 

 

 

 

B:  The secondary follicle forms as the oocyte enlarges and the granulose cells surrounding it increase in number.  Some of these granulose cells grow over and cover the oocyte, while others form a stalk or pedicle to support the oocyte.  Also during this stage of development, the empty space within the follicle beings to fill with a liquid called “hyaluronic acid.”  Arrow E points to a secondary follicle.  Locate this arrow and use it to help you to sketch (in the space here) a secondary follicle.

 

 

 

 

 

 

 

 

 

C:  The secondary follicle-but not the oocyte-continues to grow until it is about 1 centimetre in diameter.  At this stage of development, the secondary follicle becomes a Graafian follicle and the oocyte within it is now the ovum.  The pedicle becomes more defined.  Another change occurs during this stage: The granulose cells covering the ovum elongate, forming a protective cover called the “corona radiate.”  Scientists think that the corona radiate nourishes the ovum as it travels through the Fallopian tube.  Arrow F points to a Graafian follicle.  Locate this arrow and use it to help you to sketch (in the space here) a Graafian follicle.

 

 

4.       Ovulation occurs when a Graafian follicle approaches the inner wall of the ovary and ruptures. When the occur, the mature ovum or egg bursts out of the Graafian follicle, leaves the ovary, and is swept into the Fallopian tube.  Arrow G points to the right Fallopian tube. Locate and label.

5.       The open end of a Fallopian tube (the end nearest the ovary) is wide and funnel shaped. Attached to this structure are finger like structures  called  “fimbriae.” Lining the inner surface of the fimbriae are a hair like cilia. The beating action of these cilia helps to sweep the ovum into the Fallopian tube. Arrow L points to the fimbriae. Locate this arrow and label it “fimbriae.”

6.       Cilia are also located on the inner membrane of the Fallopian tube. Their beating action helps to direct the sperm to the uterus. The uterus is a muscular organ; a fertilized eff attaches to its walls while it develops into a baby.  Arrow H points to the uterus.  Locate this arrow and label it “uterus.”

Level One Questions:

1.       List the main structures of the female reproductive system.

_____________________________________________________________________________

_____________________________________________________________________________

_____________________________________________________________________________

_____________________________________________________________________________

 

2.       The ________________________________ is the muscular tube that begins at the opening of the female reproductive tract.

3.       At birth , about how many primary oocytes are stored in the ovaries? ___________________

4.       The ___________________________________ cycle is the monthly cycle, during which certain changes occur within the female reproductive system.

5.       A ripened ovum is contained in a transparent vesicle called a __________________ follicle.

6.       The _______________________ _______________________ remains relatively dormant until the female reaches puberty.

7.       The _______________________ _______________________ forms as the oocyte enlarges and the granulose cells surrounding it increase in number.

8.       After the secondary follicle reaches about 1 centimetre in diameter, it becomes a

___________________________________________________ follicle.

9.       Ovulation occurs when a Graafian follicle approaches the inner wall of the ________________________  and _______________________________.

Level Two Questions

10.   Describe the functions of each of the following structures:

a.       Vagina                                                                                                                                         

_                                                                                                                                                    

_                                                                                                                                                    

b.      Ovary                                                                                                                                           

_                                                                                                                                                    

_                                                                                                                                                    

c.       Fallopian tube                                                                                                                          

_                                                                                                                                                    

                                                                                                                                                       

d.      Uterus                                                                                                                                         

_                                                                                                                                                    

_                                                                                                                                                    

11.   What is the corona radiate?  How does it benefit the ovum?

_                                                                                                                                                            

                                                                                                                                                               

                                                                                                                                                               

12.   What is hyaluronic acid?

_                                                                                                                                                            

13.   What is fimbriae?  What is the function of these structures?

_                                                                                                                                                            

_                                                                                                                                                            

 

Level Three Question:

14.   What could happen if two ova were to reach maturity at the same time, reach a Fallopian tube successfully, and find a sufficient supply of sperm awaiting them?

_                                                                                                                                                                            

_                                                                                                                                                                            

Bonus Points:

You may find the subject of twinning fascinating.  If you do, your teacher may encourage you to investigate the events that lead to fraternal twins, identical twins, mirror twins, conjoined (Siamese”) twins, and other multiple births.

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