OUTLINE OF MALE AND FEMALE SEX CHARACTERISTICS

Back to the main reproduction page

Male

1. Pituitary gland at the base of the brain produces:

a.      FSH (follicle stimulating hormone)

1.     FSH regulates spermatogenesis.

a.      LH (luteinizing hormone)

1.     LH (produced by the pituitary) prompts Leydig cells to produce testosterone, the male hormone.

 

1. Penis

 

 

 

 

 

 

 

 

a. urination

 

 

 

 

b. sexual intercourse

 

 

 

 

 

 

 

 

 

1. Corpus cavernosum- spongy tissue that fills with blood to make penis erect

 

 

2. Glans- the head, end of penis

 

 

3. Foreskin

 

 

 

i. Covers glans, can be pulled back

 

 

 

ii. May be removed surgically in an operation (circumcision)

 

2. Scrotum

 

 

 

 

 

 

 

 

a. Located behind penis

 

b. Contains two testes

 

c. Temperature sensitive (Sperm must be made in cooler conditions)

 

 

1. Holds testes close to body when cold

 

 

2. Relaxes to hold testes from body when warm

 

 

3. Furnished with sweat glands

  

3. Testes

 

 

 

 

 

 

 

 

a. Sperm is produced by the seminiferous tubules due to FSH

 

b. Testosterone is produced by Leydig cells due to LH

 

 

1. Testosterone causes the development of the male sex organs at ~8 weeks after conception.

 

 

2. Testosterone is responsible for facial, armpit, and pubic hair, bone growth and muscular development.

 

c. Testes are formed in the abdomen before birth. They descend through the "inguinal canal" during fetal or post-natal life. Sometimes it may take months/years to reach right place. This is a possible site for a hernia.

 

4. Epididymis:

Stores sperm until they have matured

 

 

 

5. Vas deferens:

Tube that leads from the epididymis to the urethra

 

Many sperm cells are stored here too

 

 

 

6. Prostate gland:

Provides an alkaline fluid that can protect sperm from harsh vaginal acids.

 

 

7. Seminal Vesicles:

Produce food for sperm. The food is called "Fructose"

 

 

8. Cowper's gland:

Produces clear lubricating fluid

 

 

 

 

 

Sex Characteristics of the Female

1. Pituitary gland at the base of the brain produces:

b.     FSH (follicle stimulating hormone)

2.     FSH (produced by the pituitary) causes follicles and respective ova to mature.

3.     FSH also stimulates estrogen production.

b.     LH (luteinizing hormone)

2.     LH (produced by the pituitary) causes ovulation- release of ovum from ovary. Ovulation generally occurs every 28 days- this is not when a female gets her period- cycle usually irregular for first year or so

3.     LH causes the corpus luteum to produces progesterone and estrogen. Progesterone is the hormone of pregnancy.

2. Ovaries produce:

a.      Ova: each ovary contains immature ova (eggs) in follicles. Females are born with lifetime supply of eggs. (250,000-400,000 in each ovary) - ovaries release ovum - they don't make them. Almost all ova degenerate between birth and puberty. 400 eggs will be ovulated over woman's life. An egg is the largest human cell. Ovaries are located lower abdomen. 1 left, and 1 on the right.

b.     Estrogen: is produced in the ovary - the main female hormone.

1.     Estrogen increases size of oviducts, uterus, and vagina.

2.     Estrogen is responsible for secondary sexual characteristics: Fat in breasts and development of duct system. Broadening of the pelvis. Soft and smooth skin. Fat in buttocks and thighs. Pubic hair. Sex desire.

c.      Progesterone is produced by the corpus luteum. The placenta will take over from the corpus luteum and continue making progesterone during the pregnancy.

1.     Progesterone is the hormone of pregnancy.

2.     It calms the muscular contractions of the uterus.

3.     It (along with estrogen) thickens the lining of the uterus.

3. Fallopian tubes

a.      Two thin tubes attached to the upper sides of uterus

b.     The tubes terminate near the ovaries but are not attached

c.      "Fimbriae" are finger-like structures on the end of each tube

d.     Tubes conduct egg to uterus by use of small hairs called "cilia"

e.      Fertilization of ovum takes place in the fallopian tubes. They egg is viable for only 24-48 hours after ovulation.

4. Uterus

a.      Pear-shaped organ located in lower abdomen

b.     Muscles (myometrium) stretch to allow baby to develop. Oxytocin starts labor contractions.

c.      Lining of uterus (endometrium) thickens with blood-rich tissue due to progesterone

d.     Endometrium supports embryo/fetus during growth

e.      Placenta (the after birth) attaches to endometrium. It is the interface between baby and mother.

f.       If not pregnant, lining breaks down and is discharged from body through vagina. This is menstruation (period)

g.     Cervix connects uterus to vagina. It is like a door that opens during ovulation. Cervical mucous closes the door at all other times.

 

5. Vagina

a.      Where menstrual blood leaves the body

b.     Birth canal

c.      Organ in which the male inserts his penis during intercourse

d.     Very muscular, stretches to allow a baby to grow

e.      Vaginal opening partly closed by thin membrane of tissue called hymen- hymen may be stretched or torn during first intercourse or any physical activity

6. Cervix

a.      Mucous prevents bacteria and viruses from entering uterus

b.     Lets sperm into uterus after ovulation

c.      Opening of uterus into vagina

d.     Located at inner end of vagina

e.      Where baby also passes through during vaginal birth

7. Labia

a. 2 layers of skin which fold over the opening to vagina and urethra

b. Inner labia

c. Outer labia

1.Two folds of skin, surround vaginal area

2. Pubic hair grows on outer labia

8. Clitoris

a.      Small organ, 5 to 10 millimeters long

b.     Located at junction of inner labia near front of body

c.      Contains erectile tissue

d.     Sexually sensitive