Reproduction in human
Male reproductive system
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Identify and name on diagrams of the male reproductive system: the testes, scrotum,
sperm ducts, prostate gland, urethra and penis,and state the functions of these parts
Part Function
Scrotum A sac that holds the tests outside the body, keeping them cooler
than the body temperature
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Testes Male gonads that produce sperm, the male sex hormones –
testosterone
Epididymis A mass of tubes in which sperm are stored
Prostate gland Adds fluid and nutrients to sperm, to form semen
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Seminal vesicle Adds fluid and nutrients to sperm, to form semen
Sperm duct Muscular tube that links testis to urethra for passage of semen
Urethra A tube to pass semen containing sperm through the penis, and also
carries urine from the bladder at different times.
Penis Can become firm, to insert into the vagina of the female during
sexual intercourse, to transfer sperm.
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Female reproductive system
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Dr
OL. BIOLOGY 129 DR . MOUSTAFA HENIDY
( 0610-0970 ) ( 0563726730)
Identify and name on diagrams of the female reproductive system: the ovaries,
oviducts, uterus, cervix and vagina, and state the functions of these parts
Part Function
Ovary Contains follicles in which ova are produced, also secrets the
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female sex hormones- oestrogen and progesterone
Funnel of oviduct Lined with cilia to direct the ovum from the ovary into the
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oviduct
Oviduct Carries the ovum to the uterus, by movement of cilia and
( fallopian tube ) propulsion by muscles in the wall, it is the site of fertilisation
Uterus Place where the fetus develops – has very thick muscular
walls- can stretch in pregnancy
Cervix A ring of muscle that separts the vagina from the uterus
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Vagina Receive the male penis during sexual intercourse, sperm are
deposited here
Urethra Carries urine from the bladder
Fertilisation
Is the fusion of the nuclei from a male gamete (sperm) and a female gamete (egg cell/ovum)
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• Compare male and female gametes in terms of size, structure, motility and numbers
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/M
Dr
OL. BIOLOGY 130 DR . MOUSTAFA HENIDY
( 0610-0970 ) ( 0563726730)
P .o .c Male gametes ( sperm) Female gametes (egg/ovum)
Size Small (40-60 𝜇𝑚) Large ( 100𝜇𝑚)
Structure The parts of the sperm The parts of egg The egg
1.The head contains: 1.has a large nucleus containing one haploid
• A large nucleus with small amount of cytoplasm. set of chromosomes.
The nucleus carries a haploid set of chromosomes. 2. has abundant cytoplasm which may
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• An acrosome. The acrosome is a sac containing contain a small amount of yolk- an energy
enzymes. These enzymes break down part of the store .
egg membranes so that the sperm can penetrate 3.egg is surrounded by a cell surface
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the egg during fertilisation. membrane. The cell surface membrane is
2.Middle piece surrounded by an outer membrane(jelly
The middle piece contains numerous mitochondria. coat) that act as protection to the ovum as
The mitochondria provide energy for the sperm to it passes down the oviduct and then a
swim to the egg. barrier to the entry other of other sperms
2.Tail after fertilisation
The beating movement of the tail or flagellum
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enables the sperm to swim towards the egg. We
say that the sperm is motile because it can move
on its own.
Motility Able to move ( are motile) Unable to move by their own
Needs to be moved by the cilia that line
the oviduct.
By peristalsis of the oviduct
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Numbers Many / all the time One per month
Sexual intercourse
• When stimulated, the spongy tissue in the penis fills with blood and become firm. During
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intercourse, penis is inserted into the vagina and semen is ejaculated from the penis
into the neck of the vagina near the cervix. Muscles in the wall of the sperm ducts help
to propel the semen forwards.
• Using their tails, the sperm swim from the vagina, through the cervix and uterus, into
an oviduct. This process requires a huge amount of energy which is provided by
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mitochondria in the form of ATP. About a million sperm are deposited, but some of
them can reach the ovum in the oviduct.
/M
Dr
OL. BIOLOGY 131 DR . MOUSTAFA HENIDY
( 0610-0970 ) ( 0563726730)
Fertilisation
• Fertilisation may occur if there is an ovum
passing down the oviduct. A single sperm
penetrates the membrane of the ovum by
secreting a protease enzyme contained in a
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vesicle in the sperm head. Only the head of
the sperm enters the ovum; the tail is left
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outside. The sperm nucleus fuses with the
ovum nucleus to form zygote. A zygote is a
single cell formed as a result of the fusion of two gametes.
• As soon as a sperm enters the ovum, the membrane of the ovum becomes impenetrable,
so that no other sperm can get in. other sperm will die.
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• Sperm can remain active in the oviduct for at least 2 days and the ovum may take a day
to pass from the ovary to the uterus, so there is a fertile period of 3 to 4 days around
ovulation when fertilisation can happen.
• The zygote starts to divided by mitosis to form a ball of cells ( a blastula ). It continues
to move down the oviduct until it reaches the uterus. It obtains food from the yolk of
the ovum.
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Implantation
• It takes several days for the blastula to reach the uterus. By this time it is a ball of 16-
32 cells. The blastula embeds in the spongy lining of the uterus. This is called
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implantation
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Dr
OL. BIOLOGY 132 DR . MOUSTAFA HENIDY
( 0610-0970 ) ( 0563726730)
