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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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functions
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

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

Functions:

  • Produces eggs
  • Secretes hormones
  • Nurtures and protects a developing baby during 9 months of pregnancy
ovaries
Ovaries
  • 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.
ovulation
Ovulation
  • 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.
ovulation1
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.
ovulation2
Ovulation
  • 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”).
ovulation3
Ovulation
  • 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.

Estrogen-

  • 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

Progesterone-

  • 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

Functions:

  • 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
Uterus
  • 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.
uterus1
Uterus

Functions:

  • 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.
uterus2
Uterus

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.
uterus3
Uterus

Three layers:

  • Epimetrium-outer serosal layer.
  • Myometrium-middle, smooth, muscular layer.
  • Endometrium-inner layer, composed of two 2 layers,
endometrium
Endometrium

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.

vagina
Vagina
  • 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.
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