Making Babies
6.6 Human Reproduction
http://www.images-photography-pictures.net/baby-picture-quiet-childish-david-baby.jpg
The Male plumbing
• Do you think you
know it?
• Try to label all the
bits……
http://www.student.loretto.org/anatomyphys/Keydiagram-male-ReproductiveSystem.jpg
Check your answers
1 Vas deferens
2 Seminal vesicle
3 Prostate gland
4 Cowper's glands
5 Epididymis
6 Testis
7 Scrotum
8 Penis
9 Pubic symphysis
10 Bladder
11 Urethra
The Female
plumbing
http://www.student.loretto.org/anatomyphys/Keydiagramfemale--ReproductiveSystem.jpg
Check your answers?
1
2
3
3a
4
5
5a
6
7
8
9
10
11
Ovary
Fallopian tube
Uterus
Cervix
Vagina
Clitoris
Prepuce
Labia magora
Labia minora
Pubic symphysis
Bladder
Anus
Perineum
Did you get it all correct?
Do you know what each bit
does?
What do the bits do?
Lets take a “day in the life of a sperm”!
1. Sperm cells are made in the testis.
The testes make 300,000,000
sperm a day. (Which type of cell
division do they use?)
They work best at 33-34oC
They also produce Testosterone.
A male has about 250m of tubes in
their testes to make sperm.
2. Once made they are
stored in the Epididymus
(about 35m long) until
they’re needed.
http://www.e-rham.com/img/atcl4_testes.gif
A Sperm cell.
Think about how it’s
structure lets it do its job.
What does the Acrosome
do?
What is special about the
nucleus of a sperm cell?
Why does it need so
many mitochondria?
Try to find a movie of a
sperm swimming. What
could you use to model
this?
http://wpcontent.answers.com/wikipedia/commons/thumb/0/03/Complete_diagram_of_a_human_spermatozoa.svg/350pxComplete_diagram_of_a_human_spermatozoa.svg.png
Seminal Vesicles add Semen
• These are two bags located
between the bladder and the
rectum. They produce a thick
alkaline fluid and pass it into
the ejaculatory duct. This
secretion keeps the sperm
alive makes up about 60% of
the volume of semen.
• Semen is a mixture of sperm
and the secretion of various
glands, the seminal vesicles,
prostate glands and the
bulbourethral gland.
•The average volume of
semen for each ejaculation
is 2.5 to 6ml and the
average range of sperms
ejaculated is 50 to 100
million/ml
(How many sperm per
ejaculate?)
http://www.medindia.net/patients/patientinfo/images/prostate-gland.jpg
The Prostate Gland
• This controls which tube is connected to
the urethra- from the bladder or from the
Vas Deferens.
It is normal for a man to be unable to
urinate while sexually aroused!
Prostate cancer tends to develop in men
over the age of fifty and although it is
one of the most prevalent types of
cancer in men, many never have
symptoms, undergo no therapy, and
eventually die of other causes.
http://jbooy.files.wordpress.com/2008/11/prostate_enlarged_z.jpg
The Penis
• Average size?
http://v-more.com/imgz/standart/1193460436484.gif
The engorgement of the corpus
cavernosum and subsequent
erection is triggered by a shortlived neurotransmitter, nitric oxide.
A clitoris has as many nerve
endings as are found in the Glans
penis, just packed more closely.
http://en.wikipedia.org/wiki/File:Penis_frequency.svg
Sorry about the non-metric units!
5 inches = 12 cm
6inches = 15cm
7inches = 18cm
Rasputin had a
reputation…..
http://www.perpetualocean.com/tetherdcow/cowimage/rasputin1.jpg
There is some doubt as
to if the object in the jar
was really his!
http://img.dailymail.co.uk/i/pix/2007/11_02/rasputinBBC1711_468x556.jpg
Erection – if your interested…
• The spongy tissue fills with blood, from arteries down the length of
the penis. A little blood enters the corpus spongiosum; the
remainder engorges the corpora cavernosa, which expand to hold
90% of the blood involved in an erection, increasing both in length
and in diameter. The function of the corpus spongiosum is to
prevent compression of the urethra during erection.
• Blood can leave the erectile tissue only through a drainage system
of veins around the outside wall of the corpus cavernosum. The
expanding spongy tissue presses against a surrounding dense
tissue (tunica albuginea) constricting these veins, preventing blood
from leaving. The penis becomes rigid as a result. The glans penis,
the expanded cap of the corpus spongiosum, remains more
malleable during erection because its tunica albuginea is much
thinner than elsewhere in the penis.
• Take a look at this animation
http://www.1on1health.com/web/info/erectilefunction/english/erectile
-function-animation/AnimationPage/LookListenLearnType=1
The four E’s of SEEEEX
•
•
•
•
Excitement Erection – See the previous slide
Emission – What happens in the seminal vesicle.
Ejaculation - the "pressure chamber" theory, is outlined
in The Science of Orgasm (2005) by Barry Komisaruk
and colleagues.
1. Ducts fill with seminal fluid.
2. Fluid pressure builds up behind a closed sphincter
valve, creating a "pressure chamber."
3. Sudden release of the valve causes fluid to shoot
out of urethra.
4. Rinse and repeat.
Kamisaruk, Barry, et al. The Science of Orgasm (2005).
Copulation
• The sexual union of two individuals,
resulting in insemination or deposition of
the male gametes in proximity to the
female gametes. http://www.answers.com/topic/copulation-1
• In humans “proximity” means with the
penis inserted inside the vagina.
• Do not confuse this with fertilization!
http://www.health24.com/images/_content/male_female_intercourse.jpg
Be sure to notice that the Penis does not enter the Uterus!!!
There are many more positions that a human can use
The Vagina
• Is lined with
mucus secreting
cells to lubricate
intercourse.
• Is lined with
erectile tissuue
similar to the
penis. It swells
with arousal.
• Is acidic. Why?
• Some world
cultures are
fascinated with
Hymens……
http://pics1.frozenbear.com/i/picfu1/2008/09/21/10/c/0/4/c04c4f8431796eba32d41
d9792b55a200_main.jpg
The Cervix.
http://i.ehow.com/images/GlobalPhoto/Articles/4412548/cervix_Full.jpg
• It is normally very
small but the hole
in the middle can
expand to 10cm to
let a baby out.
• When not giving
birth there is
normally mucus
blocking it. Why?
• The mucus
changes structure
during the time of
ovulation to allow
sperm to get
through.
The uterus
• Has a lining that is
replenished every
cycle called the
Endometrium.
• This gives a fresh
new tissue “bed” for
a fertilised egg to
implant in.
• Shedding the
endometrium is
Menstruation.
http://www.thecancerblog.org/images/blogs/9-2007/uterus-436890.jpg
Fallopian tubes
• There are 2 – one to
each ovary.
• They are lined with
ciliated epithelium that
create a current to waft
the egg down towards
the uterus. Why do
eggs need this help
and not sperm?
• Fertilisation normally
occurs here.
http://www.fertility.com/Images/tube_fertilisation_tcm38-555.jpg
Ovaries
http://academic.kellogg.cc.mi.us/herbrandsonc/bio201_McKinley/f28-4a-d_ovary_c.jpg
•
•
•
•
Make ova,
Make progesterone
Make oestrogen
There are 2 of
them!
• This picture shows
the various stages
of follicle/ova
production – not all
the stages happen
at once!
• Each ovary makes
an ova every 56
days.
• A woman is born
with all the ova she
will ever produce
already in her
ovaries but “frozen”
at prophase of
Meiosis 1.
The menstrual
cycle
• Why should a body
willingly lose blood
and tissue? It must be
important for it to do
so!
- So that the
Endometrium is at its
freshest (with a very
accessible blood
supply) to accept a
fertilised egg.
http://www.maybe-baby.com/gallery/images/1144828120Cycle.jpg
What happens during
menstruation?
This can be split into 3 parts:
1.The hormones – Follicle stimulating hormone (FSH),
Oestrogen, Lutenising Hormone (LH) and Progesterone,
2. What happens in the ovaries – The development
of the Follicle, the development of the Corpus Luteum.
3. What happens in the uterus – the development
and shedding of the endometrium.
Basically:
1. Pituitary gland releases FSH which
travels in the blood to the ovary.
2. FSH causes the development of a
follicle which in turn produces
Oestrogen which travels in the blood
to the uterus.
3. Oestrogen causes thickening of the
endometrium.High oestrogen levels
stimulate Pituitary gland to produce
LH.
4. LH causes the scar from ovulation to
become a corpus luteum.
5. Corpus luteum produces
Progesterone with Prolongs the
endometrium.
6. When the corpus luteum heals the
drop off of progesterone allows the
endometrium to disintigrate.
7. Drop off in progesterone also allows
the pituitary to start making FSH
again.
http://www.soc.ucsb.edu/sexinfo/images/05-07-Menstrual.jpg
InVitroFertilisation
http://www.firstivf.net/ivf_steps.jpg
http://www.firstivf.net/ivf_steps.jpg
But what about the
ethics?
Think about:
World overpopulation
Playing God
Who can afford it?
What happens to
unused embryos?
Should single people
be able to elect to be
mothers?
Why not adopt? How
many orphans are
there?
Childless couples?
http://www.firstivf.net/ivf_steps.jpg