Chapter 4 NEW LIFE DEVELOPES
p. 32
Couple makes a decision to have a family
sharing in the joy
and the responsibility
This decision should be made ahead
of time
p. 33
Dating and Marriage
Many teens are physically able to have children
But not
ready Emotionally
Socially
Financially
Teen years
1. time for working toward emotional, social, & financial security
2. discover the qualities in people they like
3. helps teens develop social skills
4. learn to communicate
both verbally and Non-verbally (body language)
5. feel comfortable w/people of the opposite sex
Social
Responsibility and Social Maturity
treating all people w/ respect and
considering other people’s needs
& wishes
People who marry
1. agree to share each other’s life
2. to share the troubles as well as the joys that come their way
3. will make many important decisions together
whether or not to have children
p. 34
“When
the husband is sexually excited, he has an erection. When the wife is sexually excited, the muscles in her vagina
relax. Her vagina becomes wet with a
clear liquid. When both partners are
ready, sexual intercourse – def. the inserting of the erect penis into the
vagina might take place. The liquid in the vagina makes it easy for the
penis to enter. The husband might or
might not have an ejaculation”
during ejaculation millions of sperm pass into the vagina
most sperm swim through the cervix & into the uterus
then move into the Fallopian tubes
sperm can live up to 72 hours in the tubes
if an egg is present during this time
the sperm will try to join with it
p. 35
Each sperm has a tiny part on its head that helps wear
away the thick covering on the outside of the egg. It takes hundreds of sperm to break the egg covering, but
ONLY ONE SPERM will enter the egg.
the other sperm die
def. fertilization – when a sperm joins w/an egg
def. pregnancy – the period when a baby develops in a
woman’s uterus
STEPS OF FERTILIZATION
1. Egg is released from follicle and is swept into the Fallopian tube
2. Ejaculated sperm move up from the vagina through the uterus and into
the Fallopian tube
3. Many sperm move toward the egg
4. One sperm joins with the egg
Fertilization is complete
The other sperm will die within 72 hours
A live egg & a live sperm must be present in the Fallopian tube before fertilization can occur.
Unfertilized egg – will begin to break down after 24 hrs.
Menstruation follows in about 14 days
unfertilized egg leaves the body w/the unneeded blood and tissue
p. 36
Development of the Baby
Fertilized Egg
immediately begins to change and grow
egg divides and forms two new cells
two new cells each divide to form four cells
and so on
small group of dividing cells keep moving down the Fallopian tube
reaches the uterus in about 3 days
4 days after reaching the uterus
the group of still dividing cells attaches itself to the lining of the uterus
at this place of attachment, the def. placenta – baglike organ begins to
form
when the placenta is complete – a water like fluid fills the bag area
the developing baby floats in the fluid throughout the pregnancy
this cushions and protects the developing baby
def.
umbilical cord – cord containing blood vessels that connects the baby to
the placenta
the cord grows from the developing baby’s abdomen (later the baby’s
navel)
food and oxygen
pass from the
woman’s blood to the placenta
moves through
the umbilical cord
and enters
into the developing baby’s blood
wastes reverse
this process
in the placenta, blood vessels of the woman come close to those attached
to the baby
tiny particles of food, oxygen, pathogens (natural antibodies) move
through the walls of these blood vessels
BLOOD OF THE WOMAN DOES NOT USUALLY MIX WITH THE
BLOOD OF THE BABY
usually takes nine months for a baby to develop
p. 37
Changes During Pregnancy
will
receive a copy of this page in class
all body systems have developed by the end of the 8th week
FETUS
STAGE
development of the body systems marks the beginning of this stage
You need to mark these stages on your copy of this page.
p. 38
Passing Traits from Parents to Child
TRAITS
WERE PASSED
from your parents to you at the time
the egg was fertilized
Mother’s traits – from the egg
Father’s traits – from the sperm
passed on structures called genes
genes determine height, color of eyes & hair etc.
def. chromosomes – 46 threadlike
parts of every body cell that carry
genes (def. structures by which traits are
passed
from parent to child)
sex cells (sperm & eggs) are the only human cells that do not have
46 chromosomes
each sex cell has 23 chromosomes
at fertilization the chromosomes in the sperm join with those
in the egg bringing the total to 46 chromosomes
FOR EVERY INHERITED TRAIT –
THE FERTILIZED EGG HAS GENES FROM THE MOTHER &
GENES FROM THE FATHER
(these are your biological parents)
Chromosomes Determine Sex
Female egg – carries only X chromosomes
Male
sperm – either carries an X or a Y chromosome
“X” “X” combination = female baby
“X” “Y” combination = male baby
p. 39
Two Kinds of Genes
a mother and father each has at least two genes for every inherited trait
they pass a copy of one of these genes to their child
Brown-eyed
parents w/ blue-eyed child
each parent has a gene for brown eyes and one for blue eyes
each passes a copy of the gene for blue eyes
the baby having received none for brown eyes – becomes a blue-eyed child
Brown-eyed
parent w/ brown-eyed child
only one parent needs to pass on the gene for brown eyes
the baby receiving one gene for brown eyes – becomes a brown-eyed child
def.
recessive genes – member of a gene pair that can express itself only when
two
genes for the given trait are present
def. dominant genes – member of a gene pair that
can express itself when
only
one such gene for the given trait is present
EXAMPLES
Dominant traits – curly hair
free ear
lobes
Recessive traits – straight hair
attached
ear lobes
p. 40
Multiple Births
def.
IDENTICAL TWINS – twins who develop from
THE SAME FERTILIZED EGG
(one egg & one sperm)
they have the same traits because they develop from
the same fertilized egg
def. FRATERNAL TWINS – twins who develop from
TWO EGGS & TWO SPERM
develop at the same time but have no greater
chance of looking alike than do brothers and
sisters from born years apart
BROTHERS & SISTERS THAT DO NOT
LOOK EXACTLY ALIKE
the way a baby will look depends not only on
which genes the baby’s parents have but also
on which genes are passed to that baby
Occasionally –
three or more eggs are released from the ovaries at the same time
if these eggs are fertilized
A baby will develop from each egg