Download Embryo

What is
this?
Homunculus -A sperm cell with a
tiny human in it
-1678 – Leeuwenhoeck
– each sperm contained
a tiny preformed animal
- only needed
nourishment of the
female’s womb to grow
Fertilization
http://www.youtube.com/watch?v=6CBBzw6
xUJE
http://www.youtube.com/watch?v=Y
Yqnqr8X-Nw&feature=related
http://www.youtube.com/watch?v=09kLIsNfaO8&NR=1
https://www.youtube.com/watch?v=_5OvgQW6FG4
•Fertilization membrane
•nuclei
•egg cytoplasm
•A Fertilized Egg
•Fertilization
• – the union of sperm and egg nuclei
Zygote (fertilized egg)
Cleavage
http://www.youtube.com/watch?v=w_ydqBz
Ve9g
Sand dollar cleavage
http://www.youtube.com/watch?v=GO5YN_t1fqw
Xenopus cleavage - awesome
embryo 2 cells
Embryo
4 cells
Cleavage
In a fertilized egg, the series of cell
divisions that occur without growth
Continues until the cells of the embryo
are reduced to the size of the cells of the
adult organism
Twins
Fraternal
2 different eggs fertilized
by 2 different sperm
Identical
1 egg fertilized by one sperm;
embryo splits into two embryos
Siamese Twins
http://www.youtube.com/watch?v=BcC_qaqRTBA&
feature=related
http://www.youtube.com/watch?v=K57IcN9DWXo
Siamese twins
Cleavage to Implantation
http://www.youtube.com/watch?v=raDDvuSf
bhY
16 cell
embryo
morula
Solid ball
of cells
Morula
blastula
Hollow
center
filled
with fluid
trophoblast
Inner cell
mass
Blastocyst
When does pregnancy begin?
pregnancy begins with implantation
implantation - the fastening of the
embryo to the endometrium (wall of
the uterus)
trophoblast (outer layer of cells of
blastula) develops into the chorion secretes HCG human chorionic
gonadotropin
•Sperm gets to egg
sperm
egg
2 cells
Sperm
penetrates
egg
4 cells
Fertilization
Fertilization
membrane
8 cells
zygote
16 cells
solid ball of
cells
(morula)
solid ball
of cells
(morula)
hollow ball
of cells
(blastula)
http://www.luc.edu/depts/biology/dev/urchgast.htm
Gastrulation
http://www.youtube.com/watch?v=8v6cXkzl
EQA&feature=related
D
solid ball of
cells
(morula)
gastrula
Hollow
(blastula) gastrulation
tadpole
gastrula
ectoderm
endoderm
mesoderm
gastrulation
gastrula
ectoderm
endoderm
mesoderm
Gastrula
Stage of embryonic
development in which the
germ layers are formed
Germ layers give rise to all the tissues and
organs of animals
Differentiation
the series of changes that
transforms unspecialized
embryonic cells into specialized
cells, tissues, and organs that make
up the adult organism
What is
differentiation?
The process in which
unspecialized cells
become specialized cells
If every cell in the body
has the entire genome in
its nucleus (in other
words each cell has all
the same genes), then
what makes cells become
specialized?
Differential gene
expression
Some Genes are expressed
only in certain cells.
ex. gene for pepsin is
only active in certain
stomach cells
What is gene
expression?
When a gene is activated
and is making the
polypeptide it codes for.
Germ Layers
Endoderm
lining of
digestive
tract and
respiratory
system,
liver,
pancreas,
urinary
bladder
Mesoderm
dermis
musculoskeletal
system
circulatory
system
reproductive
organs,
excretory system
Ectoderm
epidermis
nervous
system
1. The process in which sperm and egg nuclei fuse
___________________.
fertilization
2. The structure which prevents more than one sperm from
Fertilization membrane
entering the egg_________________________.
3. The cell divisions (without growth) which the fertilized
cleavage
egg goes through ___________________.
4. The kind of cell division (nuclear division) occurring
throughout the development of the embryo is
______________.
mitosis
5. The ectoderm, mesoderm, and endoderm are called
___________________.
Germ layers
6. The ectoderm, mesoderm, and endoderm give rise to all
the structures in the fully developed animal. The
specialization of cells during this process of development is
differentiation
called____________________.
7. During cleavage, the number of cells
increases
_______________________.
8. During cleavage, the size of cells
decreases
_______________________.
A tiny fish, the embryo is formed
The three-layered stage develops to form organs
Stages having 2 and then 3 layers of cells develop
A hollow ball, made of a single layer of cells, develop
The 4, 8, 16, 32, 64, and 128 cell stages develop
The fertilized egg divides into 2 cells
Place these events in the right order
•
•
•
•
•
•
•
•
Implantation
Differentiation
Fertilization
Formation of organs
Ovulation
Gastrulation
Cleavage
Formation of placenta
•
•
•
•
•
•
•
•
Ovulation
Fertilization
Cleavage
Implantation
Formation of placenta
Gastrulation
Differentiation
Formation of organs
Sperm + egg
More cleavage
Fertilization
Blastula
(blastocyst)
Zygote
Cleavage
2 celled 4 celled
etc.
More cleavage
Morula
Hatches
Implantation
Gastrulation and
cleavage
Gastrula (germ
layers)
http://www.luc.edu/depts/biology/dev/urchgast.htm
ectoderm
mesoderm
endoderm
Gastrula
Embryo to fetus
http://www.youtube.com/watch?v=HBBNu_d
AGhs&feature=related
Each cell in a human embryo has the
same genetic material (DNA), yet some
cells become heart cells, other cells
become brain cells, and others will
develop into kidney cells (etc…)
How do the many different kinds of
cells in the body develop if they have
the same DNA?
Review:
Trace the path of sperm
from where it is produced
to where it fertilizes the
egg. List all the structures
it travels through to get to
the egg.
Testes
Epididymis
Vas Deferens
Urethra (penis)
Vagina
Cervix
Uterus
Oviduct
Fetal membranes
(extraembryonic membranes)
amnion
yolk sac
allantois
chorion
http://www.youtube.com/watch?v=LKvez9duEHQ
http://www.youtube.com/watc
h?v=tof5b1Qs_OE&feature=r
elated
amniotic fluid
chorion
allantois
Chicken
embryo
airspace
shell
albumin
yolk sac
yolk
amnion
thin, tough, membranous sac that
encloses the embryo or fetus of a
mammal, bird, or reptile. It is filled
with amniotic fluid in which the
embryo is suspended
Yolk sac
birds – stores yolk (food)
humans - blood cell formation
has no yolk
Allantois - forms primitive urinary
bladder; becomes blood
vessels on embryonic
side of placenta;
allantoic stalk becomes part of
umbilical cord (yolk sac and
allantois become the umbilical
cord)
chorion – membrane surrounding embryo
and other extra-embryonic membranes;
chorionic villi - projections of chorion
containing blood vessels; project into
maternal pools of blood
chorionic villi and uterine lining become
the placenta
chorion
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Who has a larger
egg cell,
an elephant or a
chicken?
Animal
Internal
Fertilization
Amphibians
External
Fertilization
Internal
Development
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External
Development
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Reptiles
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Birds
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Mammals
nonplacentals
placentals
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3
11
6
9
5
1
2
8
4
7
10
How could a man
become pregnant?
•placenta
http://www.youtube.com/watch?v=gHnFoWEVs7o
http://health.howstuffworks.com/ada
m-200109.htm
placenta
Placenta
Fetus
Uterus
Umbilical
Cord
Amniotic Sac
(Amnion)
Amniotic
Fluid
Umbilical Vein
Umbilical Artery
Placenta
Fetal
Capillary
Chorionic
Villus
placenta
-A temporary organ (gland) forming
from the chorion and the endometrium
from mother
What are the functions of the
placenta?
Functions of the Placenta
1.
2.
3.
4.
source of nourishment for embryo
respiratory surface for embryo
excretory organ of embryo
attaches embryo/fetus to wall of
uterus
5. secretes chorionic gonadotropin,
progesterone, estrogen regulation of pregnancy
The blood of the
embryo/fetus and the
mother do not mix!
(embryonic and maternal circulatory
systems are not connected )
How do substances get for the
mom’s blood to the fetus and
vice versa?
Substances diffusing through the placenta
From mom to embryo/fetus
Oxygen
Nutrients
Antibodies
From embryo/fetus to mom
Wastes
Human Chorionic Gonadotropin
Dangerous substances can pass through
the placenta
Viruses (e.g. measles, AIDS)
Drugs (e.g. nicotine, prescription
drugs)
Alcohol
development
http://www.youtube.com/watch?v=UgT5rUQ
9EmQ&feature=related
3 weeks
4 weeks
5 weeks
6 weeks
http://health.howstuffworks.com/
adam-200127.htm
Amniotic fluid
6 weeks
3 months
Development – series of events that give rise to a
fully grown organism
Mass – the amount of matter in an object
Premature – a baby born before it is fully developed
Fetus – the developing baby after the second
month of pregnancy; has all the organs and organ
systems formed
Embryo - A multicellular organism in an
early stage of development
Place these in the correct order:
Ovulation Stage
Menstruation
Corpus Luteum Stage
Follicle Stage
Stages of the Menstrual Cycle
Follicle Stage
Ovulation
Corpus Luteum Stage
Menstruation
What is
happening to
the 2
chromosomes
in the middle?
Crossing Over
cleavage of
embryo
implantation
uterus
Sperm
deposited in
vagina
oviduct
fertilization
egg moves
down oviduct
ovulation
https://www.youtube.com/watch?v=L3z_aJnWOM&NR=1&feature=fvwp
Week 7
•http://www.youtube.com/user/cellmedicine?v=gCVlvq7e
uek&feature=pyv&ad=7945556449&kw=ms%20cure
Stem cell therapy for MS