REPRODUCTIVE SYSTEM
Reproductive System Functions
1.
6. Meiosis I produces 2 cells, each
Production of gametes
having 23 chromosomes composed
2. Fertilization
of 2 chromatids joined at a
3. Development and nourishment of a
centromere.
new individual
7. During Meiosis II, each of the 2 cells
4. Production of reproductive hormones
divide into 2 cells and the centromere
breaks, giving separate
Gametes:
-
sex cells
-
sperm in males
-
oocytes (eggs) in females
chromosomes.
8. The final result from meiosis are four
cells, each having 23 chromosomes.
 Since the number of chromosomes
Meiosis:
are reduced during the process of
-
a special type of cell division that leads to
dividing into 4 cells, the process is a
formation of sex cells
reduction division process.
-
Each sperm cell and each oocyte
contains 23 chromosomes
Fertilization:
-
union of sperm and oocyte
Meiosis
1.
Before meiosis begins, all the
Zygote:
chromosomes are duplicated.
-
what develops after fertilization
-
develops into an embryo 3 to 14 days
2. At the beginning of meiosis, each of
the 46 chromosomes consists of 2
after fertilization
chromatids connected by a
centromere.
3. The chromosomes align as pairs in a
Embryo:
-
14 to 56 days after fertilization
process called synapsis.
4. Because each chromosome consists
of 2 chromatids, the pairing of the
Fetus:
-
56 days after fertilization
chromosomes brings 2 chromatids of
each chromosome close together.
5. Genetic material is exchanged on
occasion, when a part of a chromatid
of 1 chromosome breaks off and is
exchanged with part of another
chromatid from the other
chromosome, in a process termed,
crossing over.
Human Anatomy and Physiology with Pathophysiology 2018
REPRODUCTIVE SYSTEM
Male Reproductive System
 The male reproductive system
consists of the testes, a series of
-
new sperm
-
 The ducts include the epididymis, the
oocytes
-
flagellum and becomes motile
 Accessory glands include the seminal
bulbourethral glands.

Supporting structures include the
scrotum and the penis.
Scrotum:
-
contains testes
-
contains dartos muscle that moves
Ductus deferens:
-
“vas deferens”
-
extends from epididymis and joins
seminal vesicle
-
cut during a vasectomy
-
what flows here are the sperm cells
suspended in a fluid secreted by the
seminal vesicle
scrotum and testes close to and away
from body depending on
temperature
-
sperm cell must develop at
temperature less than body temp.
Urethra:
-
primary male reproductive organ
-
produces sperm
-
in scrotum
-
contain seminiferous tubules: where
same time)
Penis:
-
contain germ cells: cells that sperm
cells arise from
contain sustentacular cells: nourish
germ cells and produce hormones
Epididymis:
-
3 columns of erectile tissue which fill
contain interstitial cells: secrete
testosterone
corpus cavernosum, corpus
spongiosum, spongy urethra:
sperm is produced
-
passageway for urine and male
reproductive fluids (but not at the
-
-
extends from urinary bladder to the
end of penis
Testes:
-
this is where spermatids from the
seminiferous tubules able to gain the
ductus deferens, and the urethra.
vesicles, the prostate gland, and the
where sperm continue to mature
develop ability to swim and bind to
ducts, accessory glands, and
supporting structures.
where seminiferous tubules empty
with blood for erection
-
transfer sperm from male to female
-
excrete urine
Seminal Vesicles:
-
next to ductus deferens
-
helps form ejaculatory duct
thread-like tubules on side of each
testis
Human Anatomy and Physiology with Pathophysiology 2018
REPRODUCTIVE SYSTEM
Prostate gland:
-
surrounds urethra
-
size of a walnut
Bulbourethral gland:
•
produces alkaline secretions which
neutralize acidity of male urethra and
female vagina
Bulbourethral gland:
-
small mucus secreting glands near
base of prostate gland
Testicular secretions:
•
include sperm and small amount of
fluid
Semen:
-
•
•
60% of fluid is from seminal vesicles
-
30% of fluid is from prostate gland
-
5% of fluid is from bulbourethral
gland
-
5% of fluid is from testes
Seminal vesicles:
•
provide fructose (use as an energy
source for the sperm cell)
•
contain prostaglandins which
decrease mucus thickness around
cervix and uterine tubes and help
sperm move through female
•
Sperm can live for 72 hours once
inside female
sperm
-
1 milliliter of semen contains 100
million sperm
provides a transport medium and
nutrients that protect and activate
2 to 5 milliliters of semen is ejaculated
each time
mixture of sperm and secretions from
glands
-
•
Path of Sperm
1.
Sperm develop in seminiferous
tubules (testes)
2. Epididymis (maturation site)
3. Ductus deferens
4. Receive secretions from seminal
vesicles, prostate gland, and
bulbourethral gland
5. Urethra where semen (sperm) exit
body
Spermatogenesis:
reproductive tract
 formation of sperm cells
contains coagulants that help deliver
 begins at puberty
semen into female
 interstitial cells increase in number
and size
Prostate gland:
•
contains enzymes to liquefy semen
after it is inside female
•
 seminiferous tubules enlarge
 seminiferous tubules produce germ
cells and sustentacular cells
neutralizes acidity of vagina
Human Anatomy and Physiology with Pathophysiology 2018
REPRODUCTIVE SYSTEM
Production of Sperm Cells
1.
Germ cells
2. Spermatogonia
Male puberty:
•
begins to produce male hormones
3. Primary spermatocytes
4. Secondary spermatocytes
5. Spermatids
6. Sperm cells
Sperm Cell Structure
sequence of events in which a boy
and sperm cells
•
begins at 12 to 14 and ends around 18
•
testosterone is major male hormone
•
secondary sexual characteristics
develop:
Example - skin texture, fat
Head:
distribution, hair growth,
 contain a nucleus and DNA
skeletal muscle growth, and
larynx changes
Midpiece:
 contain mitochondria
Tail:
 flagellum for movement
Male Sex Hormones
Gonadotropin-releasing hormone (GnRH) is
produced in the hypothalamus and
stimulates secretion of LH and FSH.
Luteinizing Hormone (LH) is produced in the
anterior pituitary and stimulates secretion of
testosterone.
Follicle-stimulating hormone (FSH) is
produced in the anterior pituitary and
prompts spermatogenesis.
Testosterone is produced in the interstitial
cells in the testes and is involved in
development and maintenance of
reproductive organs.
Inhibin secreted by cells of the seminiferous
tubules and inhibits FSH secretion.
Male Sex Act
The male sex act is a complex series
of reflexes that result in erection of
the penis, secretion of mucus into the
urethra, emission, and ejaculation.
Emission is the movement of sperm cells,
mucus, prostatic secretions, and seminal
vesicle secretions into the prostatic,
membranous, and spongy urethra.
Ejaculation is the forceful expulsion of the
secretions that have accumulated in the
urethra to the exterior.
Sensations, normally interpreted as
pleasurable, occur during the male sex act
and result in an intense sensation called an
orgasm.
A phase called resolution occurs after
ejaculation in which the penis becomes
flaccid, an overall feeling of satisfaction exists,
and the male is unable to achieve erection
and a second ejaculation.
Human Anatomy and Physiology with Pathophysiology 2018
REPRODUCTIVE SYSTEM
Penile Erection
pelvis, between the urinary bladder
Erection is the first major component of the
and the rectum.
male sex act.
 Neural stimuli cause the penis to
enlarge and become firm.
Ovaries:
-
primary female reproductive organ
 Specifically, parasympathetic action
-
produces oocytes and sex hormones
potentials from the sacral region of
-
one on either side of uterus
the spinal cord cause the arteries that
-
ovarian ligaments: anchor ovaries to
supply blood to the erectile tissues to
dilate.
uterus
-
 Blood then fills small venous sinuses
called sinusoids in the erectile tissue
suspensory ligaments: anchor ovaries
to pelvic cavity
-
and compresses the veins, which
ovarian follicle: cells in ovaries that
contain oocytes
reduces blood flow from the penis.
Uterine (Fallopian) tubes:
Penile Ejaculation
-
Ejaculation results from the contraction of
smooth muscle in the wall of the urethra and
part of uterus which extends toward
ovaries and receive oocytes
-
fimbriae are fringe-like structures
skeletal muscles surrounding the base of the
around opening of uterine tubes that
penis.
help sweep oocyte into uterine tubes
 Just before ejaculation, action
-
tubal ligation (sterilization of female)
potentials are sent to the skeletal
muscles that surround the base of the
penis.
Uterus:
-
 Rhythmic contractions are produced
that force the semen out of the
cavity
-
urethra, resulting in ejaculation.
where embryo resides and develops
-
body: main part
-
cervix: narrow region that leads to
vagina
Female Reproductive System
 The female reproductive organs
consist of the ovaries, the uterine
tubes, the uterus, the vagina, the
Uterus wall layers:
•
perimetrium (serous):
o
external genitalia, and the mammary
glands.
functions: receive, retain, and provide
nourishment for fertilized oocyte,
 In addition, muscle tension increases
throughout the body.
pear sized structure located in pelvic
•
outermost layer
myometrium (muscular):
 The internal reproductive organs of
o
middle layer
the female are located within the
o
composed of smooth muscle
Human Anatomy and Physiology with Pathophysiology 2018
REPRODUCTIVE SYSTEM
•
endometrium:
o
Prepuce:
innermost layer that is
where 2 labia minora
sloughed off during
unite over clitoris
menstruation
Vestibule:
Vagina:
-
space in which vagina
extends from uterus to outside of
and urethra are
body
located
female copulation organ that receives
penis during intercourse
-
allows menstrual flow (but not the
passageway of urine )
-
involved in childbirth
-
contains very muscular walls and a
-
Maturation of the Oocyte and
Follicle
Ovulation:
 release of an oocyte from the ovary
LH secreted from the
mucous membrane
due to
very acidic to keep bacteria out
anterior pituitary
Vulva:
-
external female sex organs
-
mons pubis, labia majora and minora,
clitoris, and vestibule
Mons pubis:
fatty layer of skin covering
pubic symphysis
Labia majora:
larger, outer folds of skin
equivalent to male scrotum
Labia minora:
thin, inner folds of skin
Corpus luteum:
 mature follicle after ovulation
 degenerates if egg is not fertilized
Oogenesis and Fertilization
 Females are born with all of their
oogonia (2 million), unlike males that
only begin to produce sperm during
puberty.
 At puberty about 300,000 to 400,000
oogonia are left.
 Puberty to menopause,
FSH
stimulates several follicles to begin
developing during each menstrual
cycle but only 1 follicle should be
ovulated.
Clitoris:
small erectile structure located
in vestibule
 Oocytes are swept into one of uterine
tubes by fimbriae.
equivalent to male penis
Human Anatomy and Physiology with Pathophysiology 2018
REPRODUCTIVE SYSTEM
 If sperm is present in uterine
tube
during ovulation oocyte could be
fertilized.
 If fertilization occurs then zygote
implants in
uterus.
 Oocyte only lives for 24 hours, so if
no sperm is present at ovulation no
zygote develops, and oocyte dies.
Female Puberty
 Begins between 11 to 13 and is usually
completed by 16
 Menarche first episode of menstrual
bleeding
 Vagina, uterus, uterine tubes, and
external genitalia to enlarge and fat is
deposited in breast and hips
 Elevated levels of estrogen and
progesterone are secreted by ovaries
Mammary Glands
-
Organs of milk production in breasts
-
Modified sweat glands
-
Female breasts begin to enlarge
during puberty
-
Consists of lobes covered by adipose
-
Lobes, ducts, lobules are altered
during lactation to expel milk
Female Sex Hormones
Follicle-stimulating hormone (FSH) is
produced in the anterior pituitary and
prompts follicles in the ovaries to begin
development.
Estrogen:
proliferation of endometrial cells
development of mammary glands (especially
duct system)
control of LH and FSH secretion
development and maintenance of secondary
sex characteristics
Progesterone:
enlargement of endometrial cells and
secretion of fluid from uterine glands
maintenance of pregnancy state
development of mammary glands (especially
alveoli)
control of estrogen, FSH, and LH secretion
development of secondary sex characteristics
Menstrual cycle:
series of changes that occur in sexually
mature, nonpregnant females
Menses:
-
uterus
-
endometrium
produced in the hypothalamus and
Luteinizing Hormone (LH) is produced in the
anterior pituitary and causes ovulation.
Average is 28 days and results from
cyclical changes that occur in
Gonadotropin-releasing (GnRH) hormone is
stimulates secretion of LH and FSH.
time when endometrium is shed from
Stages of Menstrual Cycle
Days 1 to 5 Menses (shedding of
endometrium)
•
menstrual bleeding (menses)
Human Anatomy and Physiology with Pathophysiology 2018
REPRODUCTIVE SYSTEM
•
estrogen and progesterone levels are
low
•
follicle begins to mature
Days 6 to 13 Proliferative (between end of
menses and ovulation)
•
endometrium rebuilds
•
estrogen levels begin to increase
•
progesterone levels remain low
•
follicle matures
Day 14 Ovulation
•
oocyte is released due to LH
•
estrogen levels high
•
progesterone levels are increasing
•
cervical mucus thins
Days 15 to 28 Secretory (between ovulation
and next menses)
•
endometrium is preparing for
implantation
•
estrogen levels decrease (low)
•
progesterone levels high
•
cervical mucus thickens
Menopause
 time when ovaries secrete less
hormones and number of follicles in
ovaries is low (NOTE: Females’
oocytes are numbered).
 menstrual cycle and ovulation are less
regular
 hot flashes, fatigue, irritability may
occur
 estrogen replacement therapy may
be used to decreases side effects
Female Sexual Behavior
 Sexual drive in females, like sexual
drive in males, is dependent on
hormones.
 Testosterone-like hormones, and
possibly estrogen, affect brain cells
(especially in the area of the
hypothalamus) and influence sexual
behavior.
 Testosterone-like hormones are
produced primarily in the adrenal
cortex.
 Psychological factors also play a role
in sexual behavior.
 The sensory and motor neural
pathways involved in controlling
female sexual responses are similar to
those found in the male.
Female Sex Act
 During sexual excitement, erectile
tissue within the clitoris and around
the vaginal opening becomes
engorged with blood.
 The mucous glands within the
vestibule secrete small amounts of
mucus, with larger amounts extruded
into the vagina through its wall.
 Stimulation of the female’s genitals
during sexual intercourse and
psychological stimuli normally trigger
an orgasm, or climax.
 The vaginal and uterine smooth
muscle, as well as the surrounding
skeletal muscles, contract
rhythmically, and muscle tension
increases throughout much of the
body.
Human Anatomy and Physiology with Pathophysiology 2018
REPRODUCTIVE SYSTEM
 After the sex act, there is a period of
resolution, which is characterized by
an overall sense of satisfaction and
relaxation.
Note: Refer to the pictures in the book for the
structures. 
Human Anatomy and Physiology with Pathophysiology 2018