Human Reproductive System
Learning Targets
• I can describe three functions of the male reproductive
system.
• I can describe three functions of the female reproductive
system.
• I can define the parts of the male and female
reproductive system and label the diagrams correctly.
• I can define pregnancy related terms and male and
female secondary sex characteristics.
• I can understand the menstrual cycle and how (and
when) a female may become pregnant.
Male Reproductive System
Side View
Urinary bladder
Vas deferens
Urethra
Penis
Epididymis
Seminal
vesicle
Prostate gland
Bulbourethral gland
Testis
Scrotum
Male Reproductive System
Front View
Urinary bladder
Vas deferens
Urethra
Penis
Epididymis
Testis
Seminal vesicle
Prostate gland
Bulbourethral gland
Structure and Function
• In males, the reproductive cells are called sperm.
• The functions of the male reproductive system are
• to produce sex hormones
• to produce and store sperm
• to deliver sperm to the female reproductive system
• There, a sperm cell may join with an egg, in a
process called fertilization.
Male Reproductive System
1. Testes: Location where sperm are produced
2. Scrotum: Skin-covered sac that holds the
testicles
3. Epididymis: holding area for sperm to mature
4. Vas Deferens: Muscular tubes connecting the
left and right epididymis to the ejaculatory
ducts in order to move sperm
5. Seminal Vesicle: Glands that produce a white
sticky fluid called seminal fluid. When mixed
with sperm, called semen
6. Prostate Gland: The main function is to secrete
and store clear fluid that is part of semen
Male Reproductive System cont.
7. Cowper’s Gland: Glands that secrete a clear fluid
8.
9.
10.
11.
-
known as pre-ejaculate
Urethra: Carries urine from the bladder and also
carries semen during ejaculation
Penis: External male sex organ
The sex hormone testosterone affects the production
of sperm and signals certain physical changes at
puberty.
The ejection of semen from the penis is called
ejaculation.
Several million sperm cells are released during one
ejaculation.
Ejaculation can occur when the penis is in an erect
state.
Female Reproductive System
Side View
Fallopian tube
Ovary
Uterus
Urinary bladder
Cervix
Urethra
Vagina
Female Reproductive System
Fallopian tube
Front View
Ovary
Uterus
Cervix
Vagina
Structure and Function
• The reproductive cells in females are called eggs or ova (singular,
ovum).
• The functions of the female reproductive system are
• to produce sex hormones
• to produce eggs
• to provide a nourishing environment in which a fertilized egg can
develop into a baby
Female Reproductive System
1.
2.
3.
4.
5.
6.
Ovary: The two main functions of the ovaries are to
secrete hormones and release eggs
Fallopian Tube/Oviduct: Tubes leading from the ovary
to the uterus. Carry the ovum (egg) from the ovary to
the uterus
Uterus: The main function of the uterus is to accept a
fertilized egg which becomes implanted into the
endometrium
Cervix: The lower, narrow portion of the uterus, where
it joins with the top end of the vagina
Vagina: The internal muscular tube that connects the
vulva on the outside to the cervix of the uterus on the
inside
Labia Majora/Vulva: The female external sexual organ,
including folds of skin and mucous membranes that
cover and protect the opening to the female
reproductive system
Sexual Development
• The gonads, testes and ovaries, are endocrine glands
that secrete sex hormones. Testosterone in males and
estrogen in females.
• The primary function of the gonads is not to produce
hormones, but to produce and store gametes-sperm and
eggs.
• Neither testes or ovaries are capable of producing active
reproductive cells (gametes) until puberty.
• The onset of puberty varies among individuals. It may
occur anytime from age 9 to 15.
Ovaries
The female reproductive glands
release sex hormones that
regulate egg maturation and
control changes in a female’s
body at puberty.
Testes
The male reproductive
glands release a sex
hormone that
regulates sperm
production and control
changes in a male’s
body at puberty.
Male Reproductive System
Sperm is the smallest cell in
the human body
Sperm will be produced for
the rest of a male’s life
Sperm production will slow
with age
A constant temperature of
95° is necessary for
production of sperm
The scrotum contains a
muscle that acts as a
thermostat. If body
temperature rises, the
muscles of the scrotum
relax, lowering the testes
away from the body. If the
body temperature drops,
the muscles contract,
pulling the testes closer to
the body.
Male Reproductive System cont.
• It takes sperm about 4-6 • Testosterone produces a
weeks to mature
number of secondary sex
characteristics that appear in
• Sperm live about 24-48
males at puberty-voice
hours once they mature
deepens, facial hair, and body
and are absorbed back
hair
into the body if not
ejaculated
• Passageway the Sperm
travels:
• A tiny valve at the bottom
of the bladder closes,
Testicles→ Epididymis→ Vas
making it impossible for
Deferens→ Seminal Vesicle→
sperm and urine to pass
Prostate Gland→ Cowpers
at the same time
Gland→ Urethra
The Pathway of Sperm
Seminal
vesicle
Vas deferens
Prostate
gland
Bulbourethral
gland
Sperm
Seminal
The
prostate
bulbourethral
travel
vesicles
through
gland
add
glands
adds
the
athe
fluid
vas
atestes.
add
fluid
that
deferens
athat
provides
are
produced
in
Theyto
the
a
protects
lubricating
source
seminal
the
offluid
energy
vesicles.
sperm.
that
for
aids
the
active
passage
sperm.
of
mature
and
are
stored
in the
the
epididymis.
sperm through the urethra.
Urethra
Penis
Epididymis
Testis
Female Reproductive System
• Ovum (egg) is the largest
cell in the body
• The ovaries usually
produce only one egg or
ovum per month and will
usually alternate from one
ovary one month to the
other ovary the following
month.
• However, each ovary
may produce an ovum or
several ova can be
released from one ovary.
If 2 ova are later fertilized
by sperm, fraternal twins
will result.
• Fertilization only occurs in
the Fallopian Tubes
Female Reproductive System cont.
• At the instant of fertilization
a membrane grows around
the ovum to prevent any
other sperm from
penetrating it. The fertilized
ovum, or zygote, continues
moving through the
Fallopian Tubes to the
Uterus where it attaches to
the uterine wall and begins
to grow and develop.
• The ovaries begin to produce
estrogen which in turn
produce secondary sex
characteristics-enlargement
of breast and reproductive
organs, widening of the hips,
and growth of body hair.
• Passageway the Egg travels:
Ovaries→ Fallopian Tubes→
Uterus→ Endometrium
The Menstrual Cycle
• Women usually produce only one mature egg cell each month during a
process called the menstrual cycle (MEN stroo ul).
• During the menstrual cycle, an ovary releases a mature egg.
• The egg travels to the uterus.
• If the egg is not fertilized, the uterine lining is shed and a new cycle
begins.
Factors Affecting the Menstrual Cycle
• On average, a woman’s menstrual cycle lasts 28 days.
• Factors such as diet, stress, exercise, and weight gain or loss also
affect the menstrual cycle.
• The menstrual cycle may be irregular at times, especially during
puberty.
• During menopause, the ovaries slow down their hormone production
and no longer release mature eggs.
Stages of the Menstrual Cycle
• During the first half of the cycle, an egg matures inside one of the
ovaries.
• At about the middle of the cycle ovulation occurs.
• If the egg has not been fertilized by the time it reaches the uterus, the
uterine lining breaks down.
• The blood and tissue of the thickened lining pass out of the body
through the vagina in a process called menstruation.
The Menstrual Cycle
Days 1–4 The uterine
lining is shed during
menstruation.
Maturing
Egg
Egg
Egg
Days 5–13 An egg
matures in one of
the ovaries, and the
uterine lining starts
to thicken.
Days 14–15 The ovary
releases the mature egg
during ovulation.
Days 16–22 The egg
travels through the
fallopian tube to the
uterus, and the
uterine lining
continues to thicken.
Days 23–28 The
unfertilized egg enters
the uterus.
Menstrual Discomfort
• Cramps are caused by contractions of the uterus.
• Premenstrual syndrome, or PMS, is marked by nervous tension, mood
swings, headaches, bloating, and irritability.
• The dramatic change in hormone levels that occurs before
menstruation begins may cause PMS.
Complications
• Ectopic pregnancy In very rare cases of ectopic
pregnancy, the blastocyst implants in the fallopian tube or
elsewhere in the abdomen, instead of in the uterus.
• Miscarriage The death of an embryo or fetus in the first 20
weeks of pregnancy is called a miscarriage.
• Preeclampsia Also called toxemia, preeclampsia
(pree ih KLAMP see uh) is characterized by high blood pressure,
swelling of the wrists and ankles, and high levels of protein
in the urine.
• Gestational Diabetes Diabetes that develops in
pregnant women is called gestational diabetes, and is
marked by high blood sugar levels.
Complications at Birth
• Some complications result in a surgical delivery or premature birth.
• Low birthweight and the birth of more than one baby also may cause
complications.
• A stillbirth occurs when a fetus dies and is expelled from the body
after the twentieth week of pregnancy.
Surgical Delivery
• Sometimes delivery through the cervix and vagina is not possible
because of
• the position of the fetus in the uterus
• the narrowness of the mother’s hips
• illness
• other conditions
• A cesarean section (suh ZEHR ee un) is a surgical method of birth.
• First the doctor makes an incision in the lower abdomen into the uterus, then
he or she removes the baby and placenta.
Review: Learning Targets
• I can describe three functions of the male reproductive
system.
• I can describe three functions of the female reproductive
system.
• I can define the parts of the male and female
reproductive system and label the diagrams correctly.
• I can define pregnancy related terms and male and
female secondary sex characteristics.
• I can understand the menstrual cycle and how (and
when) a female may become pregnant.