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LS Chapter 20
Endocrine/Reproduction System
Endocrine System produces
chemicals that control many
of the body’s daily activities.
It also regulates long-term
changes such as growth and
development.
Made up of;
 Glands (organs that
produces or releases a
chemicals)
 These tubes deliver
chemical directly into the
bloodstream
 Blood carries the
chemicals to specific
locations within the body
HORMONES are the
chemicals products. They
turn on, turn off, speed up, or
slow down the activities of
different organs and tissues.
Nerve impulses from the
brain release hormones.
NERVOUS SYSTEM
regulates activities and the
endocrine system regulates
them also by sending
hormones through the blood.
THEY WORK TOGETHER
What is ADRENALINE?
When a hormone enters the
bloodstream it affects some
organs because each has a
specific chemical structure.
It interacts with a specific
target cell.
Target Cells recognize the
hormone’s chemical
structure. The hormone and
the target cell fit together the
way a key fits into a lock.
Functions
The endocrine glands include;
 Hypothalamus is a tiny
part of the brain near the
middle of your head. It is
the link between the two
systems.
 Pituitary gland is just
below the hypothalamus.
It is the size of a pea and it
controls many body
activities. Signal from the
hypothalamus tell it to
release hormones. Helps
maintain homeostasis. 671
 Thyroid (All p.669)
 Parathyroid
 Adrenal
 Thymus
 Pancreas
 Ovaries in females
 Testes in males
Reproductive
System
An EGG is the female
sex cell.
A SPERM is a male sex cell.
Each one contains half the
chromosomes (23). Joined
together they are complete
with a total of 46
chromosomes.
The joining of both is called
FERTILIZATION or
Sexual Reproduction.
A ZYGOTE is a fertilized
egg.
Male Reproductive System
 Produces sperm and the
hormone testosterone.
 Testes (produces sperm)
 Scrotum (external skin
covering the testes)
* Once the sperm forms in
the testes they travel
through other structures.
Sperm mixes with fluids
called semen.
 Penis (Semen leaves the
body through this organ as
well as urine through the
urethra.)
When semen passes through
the urethra, muscles near the
bladder contract to prevent
urine and semen from
mixing.
Female Reproductive System
R
Role; to produce eggs.
If it is fertilized it will
be nourished and
develop into a baby.
 Ovaries - Produce eggs.
 Fallopian tubes - Also
called oviducts. They
are passageways for
eggs to travel from the
ovary to the uterus.
 Uterus - Hollow
muscular organ about
the size of a pear. If an
egg is fertilized it
attaches to the wall of
the uterus. If not is
breaks down and leaves
through the cervix.
Vagina - Birth canal or
muscular passageway that a
baby would leave the
mother’s body.
Menstrual Cycle
Monthly cycle of changes
that occurs in a female
reproductive system. An egg
develops in an ovary and the
uterus prepares for the arrival
of an EMBRYO.
About half way into the cycle
a mature egg is released from
the ovary into a fallopian
tube. The process in which
the egg gets released is called
ovulation. If it does not get
fertilized it will break down.
This is called menstruation.
Human Life Cycle
A ZYGOTE develops first
into an embryo and then a
fetus. (Baby)
Amniotic Sac is a membrane
that surrounds the embryo
and develops into a
fluid-filled sac.
Another membrane
forms which helps the
placenta to form; the
placenta is the link between
the embryo and the mother.
The blood vessels are located
next to the mother’s vessels.
NO blood mixes but other
substances are exchanged.
Umbilical Cord is a rope
like structure that forms
between the fetus and the
placenta.
It contains blood vessels that
link the fetus to the mother.
After 9 months to 40 weeks a
baby is ready to be born.
Birth takes place in three
stages;
1. Labor
2. Delivery
3. Afterbirth
Multiple Births
Identical Twins
A sperm
fertilizes one
egg.
The single egg splits and
forms two identical embryos.
Fraternal Twins
Two different sperm fertilize
two separate eggs. Each of
the eggs develops into an
embryo.