Transcript The Reproductive System

The Human Body: The
Reproductive System
8th Grade Science
Mrs. Christopherson
Mrs. Goede
Review
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Mitosis is the type of cell division that occurs
in non-reproductive cells.
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Produces exact copies of the parent cell
Meiosis is cell division that occurs in
reproductive cells; gametes.
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Produces egg and sperm cells with half the
genetic material of the parent cells.
23 chromosomes are contained in gametes; this
is so that when egg and sperm meet, they
produce offspring with 46 chromosomes.
Organs of the Male
Reproductive System
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Penis
Urethra
Vas Deferens
Scrotum
Testes
Bladder*
*Not a part of the reproductive
system
External Organs of the Male
Reproductive System
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Penis: the external reproductive organ,
urethra passes through the penis and allows
urine and semen to exit the body.
Scrotum: a sac or pouch which holds the
testes.
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The function of the scrotum is to maintain the
proper temperature of the testes.
Sperm is destroyed unless a temperature of 97o is
maintained.
Internal Organs of the Male
Reproductive System
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Bladder*: holds urine prior to urination. Urine
leaves the bladder via the urethra.
Urethra: a tube which allows urine and semen to
exit the body. Connects to the bladder
Vas deferens: a tube which connects the testes
to the urethra and allows semen to exit the body.
Testes: two glands which produce sperm and
hormones (testosterone)
Organs of the Male
Reproductive System
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Let’s fill in our diagrams of the male
reproductive system.
Organs of the Female
Reproductive System
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Vagina
Cervix
Uterus
Fallopian Tubes
Ovary
Organs of the Female
Reproductive System
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Vagina: also called the birth canal, a tube
leading from the uterus to the outside of the
body.
Cervix: the lower portion of the uterus; where
the vagina and uterus meet.
Uterus: a hollow, fist-sized organ located
between the bladder and rectum.
Fallopian Tubes: also called oviducts; are two
tubes connecting the uterus with the ovaries.
Organs of the Female
Reproductive System
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Ovaries: small organs on the ends of the
Fallopian tubes responsible for the production
and release of eggs (ova-pl).
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Females are born with all of the eggs they will
ever produce.
Ovaries alternate the release of eggs each month.
Like testes, the ovaries produce hormonesestrogen.
This release of the ova is called ovulation.
Organs of the Female
Reproductive System
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Lets label the parts of the female
reproductive system now.
The Menstrual Cycle
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The menstrual cycle typically lasts 28 days;
approximately 1 month.
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One cycle is the amount of time from the
beginning of one period to the beginning of the
next period.
The beginning of a period is marked by the
release of the blood and lining from the inside
of the uterus.
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This flow of blood typically lasts 3-7 days and is
called menstruation.
The Menstrual Cycle
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After menstruation, the ovaries release
hormones that tell the uterus to grow a new
lining and prepare to receive a new egg.
As the uterus prepares a new lining, one of the
ovaries releases an egg. This is called
ovulation.
 Ovulation occurs about halfway through a
woman’s cycle.
The egg travels through the Fallopian tube. If it
is not fertilized it breaks down and is released
with the lining and blood of the uterus.
Menstrual Cycle Timeline
Menstrual Cycle Timeline
The Menstrual Cycle and
Fertilization
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If the egg is fertilized by a sperm cell, the egg
will implant in the lining of the uterus and
begin to develop.
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Zygote: The first cells of a new organism; the time
from fertilization to implantation.
Embryo: The zygote is called an embryo from
implantation to 8 weeks.
Fetus: After 8 weeks of development, the embryo
is known as a fetus.
Genetics & Inheritance
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Gregor Mendel: 1822-1884.
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Austrian monk who is often called the “Father of
Genetics”
Studied the inheritance of traits in pea plants
His research has led to a greater understanding
of dominant and recessive traits, as well as how
to predict the probability of those traits in offspring
Genetics & Inheritance:
Important Vocabulary
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Phenotype: the observed traits of an organism.
Example: hair color
Genotype: the genetic makeup of an organism.
Example: the gene that says what your hair color will
be.
Gene: a region of DNA that describes a trait of an
organism.
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Example: eye color gene
Allele: a different form of a gene
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Example: brown eye color allele, blue eye color allele
Genetics & Inheritance:
Important Vocabulary
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Dominant allele: Traits that mask the effect of other
traits
Recessive allele: Traits that are masked by
dominant traits
Examples of dominant and recessive traits
Heterozygous: the organism has one dominant
allele and one recessive allele. Example: Bb
Homozygous: the organism has either 2 dominant
alleles or 2 recessive alleles. Example: BB or bb
Predicting patterns of
heredity: Punnett Squares
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A man who is heterozygous for brown eyes
marries a woman who is homozygous
recessive for blue eyes. What are the
phenotypes, genotypes of their 4 children?
B
b
b
Bb
bb
b
Bb
bb
Predicting patterns of
heredity: Pedigree Charts
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A pedigree chart is a family tree showing
genetic information.
A
represents males, while
represents
females.
or
means that the individual
shows the trait.
Married people:
Children:
Predicting patterns of
heredity: Pedigree Charts
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Pictures of the traits you can use in your
pedigree chart.
Twins
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Multiple eggs are released or there is
more than one ovulation. Both (or more)
eggs are fertilized and you have fraternal
twins.
One egg is released but splits in two.
Identical twins are made. If the egg does
not completely split in two, conjoined
twins are produced.
Chromosomal Disorders
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http://www.pregnancyinfo.net/chromosomal_abnormalities.html
http://en.wikipedia.org/wiki/List_of_genetic_di
sorders
http://www.familyvillage.wisc.edu/Lib_chro.ht
m
http://www.thetech.org/genetics/ask.php?id=2
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