Download Year 9 - Sexual Reproduction

Human Reproductive
System
1.1 – Sexual Reproduction
• Define sexual reproduction
• Define fertilization
Mrs. Degl
1.2 - Sexual reproduction in
humans
• Identify and name on diagrams of the male
reproductive system:
• Identify and name on diagrams of the female
reproductive system:
• Describe fertilization
• State process of early development an functions
• Outline the growth and development of the
• Outline the processes involved in labor and birth
1.3 - Sex hormones in humans
• Describe the roles of
testosterone and oestrogen
• Describe the menstrual cycle
Sexual Reproduction
• Definition:
– A process involving the fusion
of the nuclei of two different
gametes (sex cells) to form a
zygote.
– The production of offspring
that are genetically different
from each other.
What are Gametes
(sex cells)?
• Simply: the sperm and the egg
Female Reproductive
System
Mrs. Degl
Male Reproductive
System
Ova
Sperm Cell
Gamete Production
• Sperm – Millions
• Eggs – much less
– Humans – 1
– Mammals - 1-20
– Fish/ Amphibians – A lot
Ovulation
• Mature egg cells bursts into
oviduct
• Humans – once a month
In the Beginning
• When egg and sperm nuclei fuse
they form a zygote.
• Zygote is a single cell and
eventually develops into an
embryo.
In the Beginning
• The embryo is a ball of cells
that implants into the wall of
the uterus.
Fertilization
• Definition:
– Fusion of gamete nuclei
Fertilization
• Definition: fusion of the nuclei
from a male gamete (sperm) and
a female gamete (egg)
• Click me fertilization.
Fertilization
• Occurs in upper 1/3 of Oviduct
• Only 1 sperm can fertilize an egg
• Fertilized egg = zygote
• An average woman is pregnant
(gestational period) for 9 whole
months.
Fertilization Continued
• After ovulation, egg caught in the
funnel of the oviduct
• Funnel lined with cilia to move it
along
• Muscles in the wall of the oviduct
help move it by peristalsis
Fertilization continued
• Close to the top of the oviduct
so sperm must meet it there
• If the egg is not fertilized (824 hrs.) – it dies
Implantation
• Fertilized eggs are implanted into
thick walls of uterus
• Zygote grows into an embryo
• Embryo gets air and nutrients
through the umbilical cord
• Mom’s uterus grows with the baby
Placenta and Amnion
• Placenta grows as embryo grows
• Connects to wall of uterus
• Where nutrients , gases, and
excretory materials are exchanged
Placenta and Amnion
• Provides a barrier to toxins and
pathogens
• Some toxins like nicotine and
pathogens like rubella virus, can
pass across the placenta and
affect the fetus
Placenta and Amnion
• Amnion surrounds the fetus
• Makes liquid called the amniotic
fluid
• Helps support and protect the
embryo
Placenta and Amnion
• After 11 weeks, embryo into a
fetus
• Placenta joined to fetus by
umbilical cord with two arteries
and a vein
Ante-Natal Care (before birth)
– Diet – calcium, iron,
carbohydrates, protein
– Exercise – swimming, walking
– No smoking
– Avoid diseases
Birth
1st Trimester =
1st 12 weeks
• Heart develops first
• Neural tube develops
• All body systems appear by
Week 8 – Now a Fetus
2nd Trimester =
up to 24 weeks
• Most growth
• Looks more like a baby
• Some preemies survive at this
stage
3rd Trimester
= Up to 40 weeks
•
•
•
•
•
More growth
Kicking, rolling, stretching
Eyes open – Week 32
Lungs mature
Rotates to head-down
position, unless baby is
breech
Labor and Birth
• Labor
– Uterine contractions begin
– Cervix dilates to 10 cm.
Labor and Birth
– Amniotic fluid breaks
– Contraction of muscles in uterus walls
– Dilation of the cervix
– Passage through the vagina
– Tying and cutting umbilical cord
– Delivery of the afterbirth
Sex Hormones
• Testosterone
• Estrogen
Secondary Sexual
Characteristics - Male
• Produced by testosterone
– Deeper voice
– Chest and facial hair
– Lengthen bones
– Increased size of testes for
sperm production
Secondary Sexual
Characteristics - Female
• Induced by increased LH, FSH,
estrogen, and progesterone
hormone levels
– Pubic hair
– Widen pelvis
– Enlarge mammary tissue
(breasts)
– Begin menstrual cycles