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REPRODUCTIVE SYSTEM

-humans reproduce sexually by the union of two gametes
(one each from the female and male)
Gametes – sex cells – sperm and egg
Egg – round, has DNA in the nucleus and a large amount of
food (yolk) because it will need to survive a few days
before implantation and it will need energy as it divides.
-about 100 000 times larger than the sperm cell
sperm –

acrosome – contains digestive enzymes that help to penetrate
the egg during fertilization
head – contains a nucleus with DNA
middle piece – contains mitochondria which provides energy
for the sperm to get to the egg
tail (flagellum) – provides swimming motion to get to the egg
-gametes are produced in the gonads (female – ovaries,
male-testes) – gonads don’t become functional until
puberty when hormones stimulate the production of
sperm and the maturing & release of the egg
zygote – single cell formed during fertilization of the egg by
the sperm
Male Reproductive Structure
LSM 3.18-1 – label using pg. 231
4 main parts:
a) 2 testes
b) Excretory Ducts
epididymis, vas deferens
c) Accessory Glands
prostate gland seminal vesicle,
cowper’s gland
d) Organ for Sperm Transfer (a.k.a. the penis)
testes – develop inside the body near kidney in embryos

- move downward & appear outside the body shortly
before birth
-contained in a sac called the scrotum
-testes are found outside the body because the sperm
develop at a temperature lower than normal body
temperature (approx. 37oC) – they contain tightly
packed coils of seminiferous tubules
produced here

Seminal Vesicles – secrete an alkaline substance containing
sugar (fructose) & citric acid
nourish the sperm,
improves motility, & neutralizes the acidity of the ducts
Prostate Gland – surrounds the urethra – contractions of
smooth muscle help to push semen out explosively –
secretions make semen alkaline, & increase semen
motility & survival rate
Cowper’s Gland – secrete a substance that affects walls of
urethra; neutralizes acidity left by urine, making a
more suitable environment for passage of sperm
Semen – mixture of sperm and secretions of accessory glands
-1 ejaculation = 3-4 mL = 400 million sperm
epididymis – long narrow duct on back of testes containing
many coiled tubes where sperm are stored & continue
to mature
vas deferens – loops over pubic bone & bladder, carries
sperm from epididymis to ejaculatory duct
ejaculatory duct – a tube that carries the semen into the
urethra – dual-function tube carries urine and sperm to the
outside of the body, but not at the same time.
penis – external organ of male reproductive system

- made of 3 groups of spongy tissue:
- spongy tissues form a blunt cone at the end of the
penis called the glans
covered by a fold of skin called
the foreskin (often removed after birth)
-normally, the penis is soft and relaxed
during sexual
excitement, blood flows into spongy tissue causing an
erection
Female Reproductive system
LSM 3.18-1 – label using pg. 231
Ovaries – primary sex organs of the female

- location – back of abdominal cavity, held in place with
ligaments
Follicle Development -pg. 233, Fig. 5 - inside are many fluid
filled cavities
follicles (inside is an egg or ovum) - at
birth each ovary has 400000 follicles
-each ovum with its surrounding cells is called a primary
follicle –after puberty, the follicle stimulating hormone
(FSH) causes primary follicles to develop into secondary
follicles
-as follicle matures and enlarges, the ovary wall bulges
mature follicle bursts through the ovary wall in a
process called ovulation
the feathery ends (fimbrae)
of the oviducts (fallopian tubes) help to guide the tiny
egg into the tube – hair-like structures in the tube keep
the egg moving towards the uterus
Uterus – hollow, pear-shaped, thick-walled, muscular organ

-located above the vagina, on top of urinary bladder
- lower end of the uterus is called the cervix (narrow
entrance into the vagina)
-upper end of the uterus has 2 fallopian tubes leading to
it and the area between the two tubes is called the
fundus (usual site of implantation of the fertilized egg)

-hormones called estrogens start to be released at puberty.
These hormones stimulate follicular development and
secondary sex characteristics ( breast development, pubic
hair, deposits of fat under the skin, broader hips etc.)
Vagina – muscular passageway – birth canal
Hormones & the Menstrual Cycle
FSH – stimulates follicles to develop – see Fig. 5, pg. 233-
follicle cells produce and release estrogen (stimulates
the uterus to thicken)
-estrogen travels to the pituitary
leuteinizing hormone
(LH) is released
-LH causes the follicle to release a mature egg
-after ovulation, LH stimulates the follicular cells to form
the corpus luteum
it produces progesterone (and some
estrogen) & prepares the uterus for pregnancy
-increased levels of progesterone in the bloodstream cause
the pituitary to decrease production of FSH & LH
prevents more egg cells from being released
– if a fertilized egg does not reach the uterus, the corpus
luteum breaks down – decreased levels of progesterone -->
uterine lining deteriorates and is shed from the body
(consists of dead cells and blood) called menstruation
(occurs every 28 days)
-see Fig. 6, pg. 234

Fertilization
-during sexual intercourse, millions of sperm are deposited
in the vagina (optimally near the opening of the uterus,
called the cervix)
-when in contact with the egg, the acrosome of the sperm will
release digestive enzymes that will allow the sperm to
penetrate the egg. This union has formed the zygote. It will
divide by mitosis, eventually forming an embryo.
-egg cell is usually fertilized in the fallopian tube and then
can attach itself to the endometrium of the uterus. (marks the
beginning of pregnancy)
-if fertilization does not occur within 48 hours the egg is not
viable
Embryonic development
-once the embryo is implanted in the uterus a placenta
develops which will provide nutrition, gas exchange &
excretion from the mother. An umbilical cord will carry
these to the embryo– see Fig. 7, pg. 235
-the blood of the mom and embryo do not mix. The
nutrients, gases & wastes diffuse across the placenta.
-mom must watch what she intakes because certain
substances can harm the embryo (especially during the early
stages of development) eg. smoking, drugs, drinking etc.

-7-8 weeks features become recognizable fetus
-normal gestation period is 38 weeks (266 days)
– see table 1, pg. 235 for other mammals
-circulatory & excretory systems are fully functional at birth
but the nervous system continues to develop through
childhood.
Disorders of the Reproductive System
-several types – see Table 2, pg. 236
-regular checkups are necessary in order to detect some of
these early. Eg. Pap test- cells scraped from the cervix are
examined for abnormal cells indicating cervical cancer
STDs & AIDs
sexually transmitted diseases – passed by sexual contact

- caused by bacteria or viruses
-see Table 3 pg. 237

Acquired Immune Deficiency Syndrome – caused by human
immunodeficiency virus(HIV)
- attacks the immune system so that it has limited
defense for disease causing organisms
-transmitted through sexual intercourse, blood
transfusion or the sharing of needles with infected
persons
-many different symptoms and can be susceptible to
rare cancers

-pg. 239, #1, 4, 5, 8, 11
-W.B. pg. 178-179, Self quiz #3.18

Source: http://kdhs.ca/Website%20Documents/reproduction%20notes.pdf