Transcript The Reproductive System Chapter 26 - Wilkes

Joe Pistack MS/ED
Functions
 Reproductive system performs two functions:
Produces, nurtures, and transports ova and sperm.
2. Secretes hormones.
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Primary reproductive organs are the gonads.
Female gonads---ovaries
Male gonads------testes
Male Reproductive System
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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 System
 Secondary sex characteristics refer to special features
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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 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 System
Female Reproductive System
Functions:
 Produces eggs
 Secretes hormones
 Nurtures and protects a developing baby during 9
months of pregnancy
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
 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 Development
 Within the ovary are saclike structures called ovarian
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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 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
 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.
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.
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”).
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 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
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 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 Hormones
Progesterone works with estrogen in establishing the menstrual
cycle.
 Helps maintain pregnancy.
 Prepares the breasts for milk production after
pregnancy.
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
 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 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
 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 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
 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 or womb-
shaped like an upsidedown pear and is located
between the urinary
bladder and the rectum.
 Broad ligament-holds
the uterus in place.
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.
Uterus
Parts of the uterus:
 Fundus-upper domeshaped region above the
entrance to the fallopian
tubes.
 Body-central region.
 Crevex-lower narrow
region that opens into
the vagina.
Uterus
Three layers:
 Epimetrium-outer serosal layer.
 Myometrium-middle, smooth, muscular layer.
 Endometrium-inner layer, composed of two 2 layers,
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
 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
Female external genitals together are called the vulva.
They include:
 Labia majora
 Labia minora
 Clitoris
 Vestibular glands
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).
PMS
Menopause
As We Age
 Woman’s ovaries begin to atrophy, end of reproductive
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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.