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The Reproductive System Chapter 26. Joe Pistack MS/ED. Functions. Reproductive system performs two functions: Produces, nurtures, and transports ova and sperm. Secretes hormones. Primary reproductive organs are the gonads. Female gonads---ovaries Male gonads------testes.

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The reproductive system chapter 26

The Reproductive SystemChapter 26

Joe Pistack MS/ED


  • Reproductive system performs two functions:

  • Produces, nurtures, and transports ova and sperm.

  • Secretes hormones.

  • Primary reproductive organs are the gonads.

    Female gonads---ovaries

    Male gonads------testes

Male reproductive system1
Male Reproductive System

  • Performs three functions:

    1. Produces, nourishes, and transports sperm.

    2. Deposits sperm within the female reproductive tract.

    3. Secretes hormones.

Male reproductive system2
Male Reproductive System

  • Testes-male gonads.

  • Functions: produce sperm and secrete the male hormone, testosterone.

  • Two oval testes are located outside the abdominal cavity and are suspended in a sac between the thighs called the scrotum.

  • Testes normally descend into the scrotum during the last 2 months of fetal development.

  • Cryptorchidism-failure of the testes to descend into the scrotum, can result in sterility.

Male reproductive system3
Male Reproductive System

  • Undescended testicles are associated with infertility.

  • Sperm cannot live at body temperature, they prefer the cooler temperature of the scrotum.

  • Wearing tight underwear and jeans can elevate the temperature of the testes, thereby lowering sperm count.

Male reproductive system4
Male Reproductive System

  • The testis is divided into about 250 smaller units called lobules.

  • Each lobule contains seminiferous tubules and interstitial cells.

  • Seminiferous tubules-tightly coiled tubules where sperm is produced.

  • The interstitial cells lie between the seminiferous tubules and produce the male hormones called androgens.

  • Most important androgen is testosterone. Testes produce sperm and testosterone.

Male reproductive system5
Male Reproductive System

  • Spermatogenesis-the formation of sperm.

  • Each spermatogonium (undifferentiated sperm cell) contain 46 chromosomes, normal number of chromosomes for human body cells.

  • Under the influence of testosterone spermatogonium enlarge and form primary spermatocytes

  • Primary spermatocytes divide by a special type of cell division called meiosis.

  • Meiosis reduces the number of chromosomes by one half, a sperm will only have 23 chromosomes.

Male reproductive system6
Male Reproductive System

  • When the sperm unites with an egg, which also has 23 chromosomes, the fertilized egg will have 46 chromosomes.

  • Newly formed sperm are not functional and must undergo several maturational changes.

Male reproductive system7
Male Reproductive System

  • Sperm looks like a tadpole.

  • Sperm has: 1. a head

    2. a body

    3. a tail

  • Head is primarily a nucleus, contains the genetic information.

Male reproductive system8
Male Reproductive System

  • Front part of the head contains enzymes that help the sperm penetrate the egg at the time of fertilization.

  • Body or midpiece is a spiral-shaped structure that contains mitochondria and supplies the sperm with energy for the “Big swim”.

Male reproductive system9
Male Reproductive System

  • Tail of the sperm is the flagellum, has whip-like movements that enable the sperm to swim.

  • Most sperm live only hours after being deposited in the female reproductive tract, but hardier ones may live up to 3 days.

  • Purpose of the reproductive system is to produce offspring, this is achieved by the union of the sperm and the egg.

Male reproductive system10
Male Reproductive System

  • As the sperm form, they gather in the seminiferous tubules and then move into a series of genital ducts, where they mature.

  • They are transported from the testes to the outside of the body.

    The ducts include:

    2 epididymides

    2 vas deferens

    2 ejaculatory ducts

    1 urethra

Male reproductive system11
Male Reproductive System

  • Accessory glands-add secretions to the sperm as they travel through the genital ducts.

  • The three accessory glands are:

    1. The seminal vesicles

    2. The prostate gland

    3. The bulbourethral glands

Male reproductive system12
Male Reproductive System

Prostate gland-single gland, donut-like, encircles the upper urethra just below the bladder.

  • Secretes a milky, alkaline substance that plays a role in increasing sperm motility.

  • Counteracts the acidic environment of the vagina and helps protect the sperm as it enters the woman’s reproductive tract.

Male reproductive system13
Male Reproductive System

  • Semen-mixture of sperm and the secretions of the accessory glands.

  • About 60% comes from the seminal vesicles, the remainder comes from the prostate gland.

  • Semen is a milky white liquid with an alkaline pH.

  • Number of sperm per ejaculation is about 50 to 100 million.

Male reproductive system14
Male Reproductive System

  • External genitals-consist of the scrotum and the penis.

  • Scrotum is the sac of skin that hangs loosely and contains the testes.

  • The penis has two functions:

    1. Carries urine through he urethra to the outside of the body.

    2. Acts as the organ of sexual intercourse.

Male reproductive system15
Male Reproductive System

  • The loose skin covering the penis that extends downward and forms a cuff is called the foreskin or prepuce.

  • Circumcision is removal of the foreskin.

  • Phimosis-condition where the foreskin becomes tight and must be surgically removed.

Male reproductive system16
Male Reproductive System

  • Male sex hormones are called androgens.

  • Primary male sex hormone is testosterone.

  • Most testosterone is secreted by the interstitial cells of the testes, small amount by the adrenal cortex.

  • Secretion begins during fetal development and continues at a low level throughout childhood.

Male reproductive system17
Male Reproductive System

  • Puberty (age 10-13), testosterone secretion increases rapidly, transforming the boy into a man.

  • Testosterone is secreted continuously throughout life, and is responsible for the development of the male sex characteristics.

  • Primary sex characteristics include enlargement and development of the testis and various accessory organs such as the penis.

Male reproductive system18
Male Reproductive System

  • Secondary sex characteristics refer to special features of the male body, such as:

  • Increased growth of hair on the face, chest, axillary and pubic region.

  • Deepening of the voice due to enlargement of the vocal cords.

  • Thickening of the skin and increased activity of the oil and sweat glands.

  • Increased musculoskeletal growth and development, broad shoulders and narrow waist.

Male reproductive system19
Male Reproductive System

  • Hormones that control male reproductive system:

  • Primarily secreted by the hypothalamus, anterior pituitary gland, and the testes.

  • Hypothalamus secretes a releasing hormone

  • This stimulates the anterior pituitary gland to secrete:

    1. follicle-stimulating hormone (FSH)-promotes spermatogenesis

    2. luteinizing hormone (LH)-promotes development of interstitial cells and the secretion of testosterone

Female reproductive system1
Female Reproductive System


  • Produces eggs

  • Secretes hormones

  • Nurtures and protects a developing baby during 9 months of pregnancy


  • Female gonads

  • 2 almond-shaped ovaries located on either side of the uterus in the pelvic cavity

  • Anchored in place by ligaments

Egg development
Egg Development

  • Production of eggs begins at puberty and continues until menopause.

  • Supply of eggs exceeds actual need.

  • Each ovarian follicle consists of an immature egg.

  • Beginning at puberty, several follicles mature every month, but only one fully matures.

Egg development1
Egg Development

  • Within the ovary are saclike structures called ovarian follicles

  • Born with about 2 million follicles

  • By puberty only about 400,000 remain

  • Only 400 follicles ever fully mature

  • Typically one egg per month matures between puberty and menopause which occurs between 45 and 55

  • Each ovarian follicle consists of an immature egg called an oocyte

  • As the egg matures it undergoes meiotic cell division which cuts the chromosomes from 46 to 23

Egg development2
Egg Development

  • As the follicle enlarges, a fluid-filled center is formed, and the follicular cells begin to secrete estrogen.

  • The mature ovarian follicle is known as the graafian follicle.


  • Once a month the ovarian follicle bursts.

  • The ovary ejects a mature egg (ovum) with a surrounding layer of cells.

  • The ejection phase is called ovulation.


  • The egg travels from the surface of the ovary into the peritoneal cavity and is immediately swept into the fallopian tubes.

  • Fimbriae-fingerlike projections at the end of the fallopian tubes that sweep the egg into the fallopian tubes.


  • If the egg is fertilized, it implants itself in the uterine lining and grows into a baby.

  • If the egg is not fertilized, it dies and is eliminated in the menstrual blood.

  • Once ovulation occurs, the follicular cells that remain in the ovary develop into a glandular structure called the corpus luteum (“yellow body”).


  • Corpus luteum secretes:

    1. large amounts of progesterone

    2. small amounts of estrogen

  • If fertilization does not occur, the corpus luteum deteriorates in about 10 days and becomes known as the corpus albicans (“white body”).

  • The dead corpus is no longer capable of secreting hormones.

Ovarian cyst
Ovarian Cyst

  • Ovarian cysts occur when the corpus luteum fills with fluid.

  • A chocolate cyst occurs when the cyst is filled with blood.

  • Cysts may resolve on their own or they may require surgery.

Ovarian hormones
Ovarian Hormones

At puberty the ovaries begin to secrete estrogen and progesterone.


  • Promotes the maturation of the egg

  • Helps to develop the secondary sex characteristics

  • Gives the female the femininizing effects

Ovarian hormones1
Ovarian Hormones

Feminizing effects of estrogen:

  • enlargement and development of the organs of the reproductive system.

  • Enlargement and development of the breasts.

  • Deposition of fat beneath the skin, especially in the thighs, buttocks, and breasts.

  • Widening of the pelvis.

  • Onset of the menstrual cycle.

  • Closure of the epiphyseal discs in the long bones.

Ovarian hormones2
Ovarian Hormones


  • works with estrogen in establishing the menstrual cycle.

  • Helps maintain pregnancy.

  • Prepares the breasts for milk production after pregnancy.

Genital tract
Genital Tract

Consists of:

  • Fallopian tubes

  • Uterus

  • Vagina

    Fallopian tubes-also called uterine tubes or oviducts.

  • Each fallopian tube is about 4 inches long

  • Extend from either side of the uterus to the ovaries

Fallopian tubes
Fallopian Tubes

  • Infundibulum-funnel-shaped end of the fallopian tube nearest to the ovary.

  • Fimbriae-fingerlike projections at the end of the fallopian tubes.

  • Fallopian tubes do not attach directly to the ovary, the fimbriae hang over the ovary.

Fallopian tubes1
Fallopian Tubes


  • Tube transports the egg from the ovary to the uterus.

  • The tube is the usual site of fertilization of the egg by the sperm.

Tube troubles
Tube Troubles

  • Ectopic pregnancy-the fertilized egg implants in the fallopian tube rather than in the uterus.

  • Usually results in miscarriage, causes bleeding, possible hemorrhage, and sometimes death.

Tube troubles1
Tube Troubles

Scarring of the fallopian

Tubes :

  • Can be caused by repeated gonorrheal infections.

  • Blocks movement of the egg through the tube.

  • May cause sterility.

Pelvic inflammatory disease
Pelvic Inflammatory Disease

  • Fallopian tubes open directly into the pelvic cavity.

  • Infection spreads through the tubes into the pelvic cavity, causing pelvic inflammatory disease (PID).

  • PID is most frequently associated with sexually transmitted diseases.


  • Uterus or womb-shaped like an upside-down pear and is located between the urinary bladder and the rectum.

  • Broad ligament-holds the uterus in place.



  • Provides a safe and nurturing environment for the growing baby.

  • Baby’s cradle for 9 months.

  • During pregnancy, the size of the uterus increases to hold the growing baby and the placenta.


Parts of the uterus:

  • Fundus-upper dome-shaped region above the entrance to the fallopian tubes.

  • Body-central region.

  • Crevex-lower narrow region that opens into the vagina.


Three layers:

  • Epimetrium-outer serosal layer.

  • Myometrium-middle, smooth, muscular layer.

  • Endometrium-inner layer, composed of two 2 layers,


Inner layer, has 2 layers:

1. Basilar layer-thin and vascular, lies next to the myometrium.

2. Functional layer-responds to ovarian hormones, thickens in preparation for the fertilized egg. Layer that sloughs during menstruation. Site of Pap Smear.


  • 4-inch muscular tube that extends from the cervex to the vaginal opening in the perineum.

  • Mucosal lining of the vagina lies in folds (rugae) that are capable of expanding.

  • Folds are important for childbearing, allow the vagina to stretch and accommodate the baby during birth.

External genitals
External Genitals

Female external genitals together are called the vulva.

They include:

  • Labia majora

  • Labia minora

  • Clitoris

  • Vestibular glands

Female hormones
Female Hormones

  • A number of hormones control the female reproductive cycle.

  • Female hormone secretion occurs in a monthly cycle with a regular pattern of increases and decreases in hormonal levels.

  • Puberty in females is marked by the first period of menstrual bleeding (menarche) continues regularly until a woman reaches her 40’s or 50’s (menopause).

As we age
As We Age

  • Woman’s ovaries begin to atrophy, end of reproductive years.

  • Decrease in estrogen secretion.

  • Size of uterus decreases.

  • Weakening of bones-osteoporosis.

  • Increase in cardiovascular disease.

  • Breast tissue sags.

  • Testicular function declines.

  • 50% reduction in sperm.