Reproductive systems in
humans
Start by labelling the main parts of the male
reproductive organs – use page 100 in your
book
Key words
Penis,

pelvis,
scrotum
bladder,
prostrate gland, urethra,
epididymis,
testis,
seminal vesicle,
vas deferens
Annotating the main parts
1.
2.
3.
4.
5.
6.
Testis – secrete the male sex hormones (testesterone)
and produce the male gametes (sperm)
Epididymis – a duct which collects and stores
spermatazoa from the testis.
Vas deferens – sperm duct – spermatozoa are expelled
through this duct. Seminal fluid is added on route.
Exocrine glands – seminal vesicles and prostate glands
which secrete seminal fluid (semen) which is nutritive
and lubricating along the vas deferens
Semen contains spermatozoa, seminal fluid, mucus
and cells lost from the lining
Penis – has erectile tissue which fills with blood to
become rigid during sexual intercourse.
Main functions of male reproductive
system

To produce and expel motile male
gametes (sperm)
Label the main parts of the female
reproductive organs – use page 100 in your
book
Key words
Ovary,
cervix,
uterus,
rectum,
labia minora,
urethra,
labia majora,
rectum,
pubic bone,
clitoris,
vagina,
bladder,
oviduct
Annotating the main parts




Ovaries- site of production of the egg (ova) and
secretes the hormones progesterone and
oestrogen
Oviducts – move the ova from the ovaries to the
uterus (ciliated). Site of fertilization.
Uterus (womb) – site where the fetus implants
and develops in the lining known as the
endometrium (blood lining)
Vagina – adapted for reception of the penis and
passage of the baby during birth.
Main functions of the female
reproductive system



Produce gametes (eggs/ ova)
Receive male gametes (sperm)
Provide a suitable place for fertilization
and the development of the fetus.
Gametogenesis
Production of the gamete cells –
sperm and ova
Spermatogenesis




Spermatogenesis –
production of the
sperm.
This happens in the
testis within the
seminiferous tubules
Spermatogenesis
begins at puberty and
normally continues
throughout life.
The whole process
takes approx 74 days
It starts on the
outside of the
seminiferous
tubules. As the
sperm develop they
move inwards
toward the lumen of
the seminiferous
tubules.
The sperm are
eventually pushed
into the epididymis
and stored until
ready for
ejaculation into the
vas deferens and
beyond!!
Outside of
seminiferous
tubules
Lumen of
Seminiferous
tubules
Copy the slightly simpler diagram on page 101.
The stages
1.
2.
3.
4.
5.
Primordial germ cells (2N) lining the seminiferous
tubules divide by mitosis producing
spermatogonium (2N) type 1
Spermatogonium undergo more mitosis (and some
differentiation) to produce primary
spermatocytes.(2N)
primary spermatocytes undergo meiosis to
produce secondary spermatocytes (n)
secondary spermatocytes undergo meiosis 2 to
produce spermatids (n)
Finally the spermatids develop into spermatozoa
by a process called spermiogenesis



The sperm cell is 55
to 65 micrometres
long
The head contains a
nucleus and is
covered in an
acrosome containing
lytic enzymes (to
digest the outer coat
of the egg)
The midpiece
contains many
mitochondria needed
for energy to help the
sperm swim.
Sertoli cells


These cells act as ‘nurse cells’ for the
process of spermatogenesis. They provide
mechanical and metabolic (energy)
support the spermatozoa
They are also phagocytic and ‘eat up’ any
excess cytoplasm lost during the process.
Testosterone



Testis also produce testosterone – the
male sex hormone.
It is secreted by the leydig cells in the
testis
Testesterone controls spermatogenesis as
well as many male characteristics such as
growth of muscle, voice deepening,
behaviour (aggression)
How the brain controls
Testosterone





2 gonadotrophic hromones: Follicle stimulation hormone
(FSH) and Interstitial cell stimulating hormone (ICSH)
are released by the anterior pituitary gland.
ICSH stimulates the leydig cells to secrete testosterone.
FSH works with testosterone to stimulate
spermatogenesis
But testosterone inhibits ICSH which controls the rate of
sperm production.
So you can’t make too many sperm!!!
Quick review
Q1. Put the following in order
1.
2.
3.
4.
5.
6.
Secondary spermatocyte
Spermatozoa
Primordial germ cell
Spermatogonium
Spermatids
Primary spermatocyte
Answer










3, 4, 6, 1, 5, 2
Q2. What process happens between secondary spermatocytes and
becoming spermatids?
Meiosis 2
Q3 what is the process called where spermatids develop into spermatozoa?
Spermiogenesis
Q4. What are the ducts called where the spermatozoa are stored?
Epididymis
Q5 what are the tubes called where spermatogenesis occurs?
Seminiferous tubules
Q6/ what is the name of the nurse cells which support the spermatozoa?
Page 103- Oogenesis –
1. During early fetal development
- starts with primordal germ
cells then goes through
mitosis to form oogonia.
2.
4/5 months later, some
oogonia enlarge and become
primary oocytes. Most
oogonia degenerate at this
time.
3.
7th month (still before birth)
primary oocytes become
primordial follicles and begin
meisois but then stops until
puberty!!!
4. At puberty, once a
month, a primary oocyte
starts meiosis again.
(most primary oocytes
degenerate)
5. The follicle containing the
primary oocyte enlarges
and meiosis 1 is
completed.
6. It is now a secondary
oocyte.
7. At ovulation the mature
follicle (containing the
secondary oocyte)
ruptures and the
secondary oocyte is
released.
8. The secondary oocyte
(now known as the
ovum) moves down the
oviduct.
9. If it is fertilized by a
sperm then after the
head of the sperm has
entered the secondary
oocyte undergoes meiosis
2 to become the mature
ovum.
10. Fertilization can occur.
11. These last 3 stages
happen very quickly.
Note – all polar bodies
degenerate.
Label the points 1 - 9
The corpus luteum



After ovoulation the ruptured follicle
becomes a termpory endocrine structure,
the corpus luteum.
The corpus luteum secretes progesterone
and oestrogen for up to 12 – 14 days (it
gradually gets smaller and smaller.
If fertilization does not occur, it eventually
degenerates into a corpus albicans.