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Human reproduction

The male reproductive system

Slideshow Interactive male reproductive system

Male Repro2


Penis – the organ that sperm, and urine, passes through

Scrotum – A pouch of skin that holds the two testes (also called testicles, or gonads)

Urethra – A tube which carries urine, and semen, from inside the body, to the outside

Testicles – A pair of organs which produce sperm cells. Also makes the hormone testosterone

Vas deferens – A tube that carries sperm from the testicles to the urethra,

Seminal vesicles – Glands at the back of the bladder. They secrete semen.

Prostate gland – Also secretes semen



A hormone that starts getting produced at puberty.

* larynx (voicebox) lengthens, so the voice deepens

* enlarges size of penis and testicles

* causes facial and body hair to grow

* increases length of bones, and helps increase muscle mass

* causes skin to thicken and become more oily (can lead to acne)



The female reproductive system

Interactive Slideshow female reproductive system

Vagina (birth canal) – A muscular tube leading inside a woman’s body. Where sperm enters a woman. Also is where a baby is born from.

Cervix – The muscular wall at the end of the vagina. It has a tiny hole that sperm can swim through.

Uterus (womb) -A thick muscular organ. Has two purposes

(a) Allows sperm to pass, from the vagina, up towards the fallopian tubes

(b) If a woman becomes pregnant, the fetus will attach to the wall of the uterus and grow here.

Fallopian tubes – Tubes that connect the uterus to the ovary

(a) sperm swim up into these tubes. If the woman has recently released an egg, this is where the egg and sperm meet.

Ovary – these are where a woman’s eggs are stored. After puberty, women usually mature one egg a month.



Endometrium – the lining of the uterine walls, filled with tiny blood vessels.

(a) Each month the endometrium thickens, in anticipation of pregnancy.

(b) If pregnancy occurs, then the endometrium is kept. It is used to nourish the growing fetus.

(c) If pregnancy doesn’t occur then the endometrium is shed, and expelled through the cervical opening, out through the vagina. This process is called menstruation


Eggs are made in a woman’s ovaries, while she is still a fetus.

By birth she already has over a million eggs in her ovaries.

Once a girl is born, she won’t produce any more eggs.

The eggs are in a state of suspended development until she reaches puberty.

After puberty, (about) one egg a month finishes developing and is released.

The release is called ovulation.

Eggs are the largest cell in the body.


About every 28 days, a woman releases one egg

* sometimes from the left ovary, sometimes from the right.

* If the egg becomes fertilized then she is pregnant.


Menstrual cycle

Menstrual cycle diagrams


A) Fertilization occurs in the oviduct / Fallopian tube.
1. A fertilized egg is called a zygote.
2. Fertilization restores the complete set of chromosomes, so the zygote is diploid (23 from
the egg + 23 from the sperm = 46).
B) A zygote develops in the following order:
1. Cleavage – A form of mitosis when cells divide rapidly but do
not differentiate. Forms the embryo.
2. Differentiation – Cells specialize to form tissues and organs.
3. Implantation in the wall of the uterus.
4. Fetus – most major organs are formed (but not completed)
 Continues to grow through cell division (mitosis)
C) The placenta transfers nutrients and oxygen from the mother’s
blood into the blood of the fetus through the process of diffusion.
1. The blood of the mother and fetus do not mix.
2. The fetus is attached to the placenta by the umbilical cord.
3. Waste produced by the fetus is also removed by the placenta.
 Waste (CO2, urea, salts) diffuse from placenta into mother’s blood.
 Since the fetus does not eat solid food, it does not have to eliminate feces.
D) The child is vulnerable to alcohol, drugs, whatever the mother takes in because organs and
systems are still developing




Amniocentesis Amniocentesis image006

Reproductive technology


artificial insemination 3

Artificial insemination: using sperm from a donor

A. The woman takes a hormone. that stimulates her ovary to ripen several eggs.

B. Doctors watch what is happening inside by using ultra-sound

C. Ovulation: the ripe egg is released

D. Sperm is collected from the man.

E. They look at sperm under a microscope, and select healthy sperm.

F. They use a thin tube to insert the sperm into the vagina, right by the cervix.

Learning Standards

Massachusetts Comprehensive Health Curriculum Framework

4.1 Identify the components, functions, and processes of the reproductive system

Massachusetts Science Technology and Engineering Learning Frameowrk

7.MS-LS1-4. Construct an explanation based on evidence for how characteristic animal behaviors and specialized plant structures increase the probability of successful reproduction


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