Terms - Embryology (developmental) Flashcards
Cleavage
rapid cell division with out cell grow
- a parent cell to 2 daughter cell
Blastomeres
resulting cells that from from cleavage from a fertilized ovum
Cleavage Furrow
is the indentation on the surface of the cell
- pinches into the two daughter cells
Holoblastic
Completely separates the cell into two equal blastomeres
- an exception is frogs which undergo holoblastic
Meroblastic
when the cell goes under partial unequal cleavage that results in different size blastomeres
- the cleavage furrow doesn’t go all the way through the entire egg
Placental mammals
review all our nutrients through the mom
- wil undergo holoblastic cleavage
Yolk mammals
Birds, reptiles and fish rely on the yolk to receive there nutrients
- undergo mesoblastic cleavage
determinant Cleavage
- they know what they will become
- “it going to become part of the G.I. Tract”
Indetermination cleavage
indecisive and don’t know what genes they will express or suppress
Determination
it has decided what its going to become in the future
- genes is going to express and what genes is going to suppress
- happens before differentiation
- ex: your gonna become a dentist in the future determined
Differentiation
is when we can look underneath a microscope and see a physical change or distinction due to the cell expressing those specific genes that it decided upon
- we know see that you are a dentist and already there
Spiral Cleavage
- no pattern of alignment and is in random
- will look disorganized in its appearance
- Blastomeres will be larger and smaller then one another: Macromeres and micrometers
Radial Cleavage
- is when the cleavage furrow will either be parallel or perpendicular to the polar axis
- Organized and well structured
- Blastomeres will be the same size and on top of each other
Animal Pole
- the egg little yolk
- is very active in cleaving
- embryo grows
Vegetal pole
the egg has more yolk on the bottom, and is very slow at dividing
Polar axis
Line of symmetry, down the middle of the egg, which divides the egg from the top and bottom
protosomes
will undergo:
- Determinant
- Spiral
- Blastopore becomes the mouth first
Deuterostome
- like humans
- will undergo: indeterminant and radial
- Blastopores become the anus first
morula
is a solid ball of cells that is around 16 to 32 in number of blasphemers
Blastulation
The morula will become blastula.
- The human embryo is known as a blastocyst
- Blastula and blastocyst are analogous words referring to the same stage of development
Blastula
is a hollow, fluid-filled ball of cells
Blastocoel
A cavity which is a hollow space
Gastrulation
When the blastula becomes a gastrula
- a process which the diploblastic becomes triploblastic
Gastrula
the process of the cells surrounding the blastocoel will begin an inward folding motion and push themselves into the blastocoel
Blastopore
is the opening of the cell which was formed when folding in
- will become the mouth or anus
- it will push its way to become a opening
Archenteron
The space that is created from when the blastopore creates to go from one opening to the end
G
Germ Layer
1 of the 3 types of cell types that form from gastric
- Ectoderm: exterior lining
- Mesoderm: middle
- Endoderm: interior lining
triploblastic
- three germ layers collectively together on an animal
Diploblastic animals
- will only have two germ layers, which are Ectoderm and Endoderm
bilaminar disc
- the human embryo starts as a bilaminar disc
- which is divided into an epiblast and hypoblast
primative streak
The cell will migrate through the opening of the primitive streak that is located in the epiblast. it will then pop out into the mesoderm which is then placed in the hypoblast
notochord
is derived from the mesoderm
- located in the middle of our trilaminar sandwich
- is a hallmark feature of the phylum Chordata
- all humans have notochord curing organogenesis
induction
Is a cell influencing the development of a neighboring cell
neurulation
is a process by which the neural tube is developed
- neural tube = primitive nervous system
neural plate
Will swell and fold to create neural folds and a neural groove
Neural fold
- are developed from neural plate swelling
- when they finally contact each other, they will pitch off as a tube, collectively creating a neural tube
Neural Tube
Is the development form when two Neural folds connect with each other and pinch off
- the tube is hallow
- on top of the notochord
neural crest cells
The cells in the neural folds eventually pop off
- derived from ectoderm
Delamination
The process of when neural crest cells pop off the neural fold and migrate to create their own tissue
Ectoderm
- the exterior of the embryo
EX: hair, nails, sweat glands, mammary glands - neural tube: nervous system
- Adrenal medulla: produces epinephrine and norepinephrine
- Neural crest: Skull (bone, muscle, connective tissue), Melanocytes odontoblast (pigmentation), and P.N.S (sensory neuron, glial cells
Endoderm
- Epithelial lining: GI tract, respiratory tract, urinary tract
- excretory system
- Lungs
- Pancreas
- Liver
- Thyroid
- thymus
Mesoderm
- between ectoderm and mesoderm
- bones
- cartilage
- joints,
- muscles
- connective tissue
- circularity system: blood, vessels, heart
- Lymphatic system
- Spleen
- Adrenal cortex
- Urogenital organs
- Notochord
hox genes
- are a family of related genes that specify regions of the body genes that specify regions of the body plan of an embryo
- corrective placement of body parts, like arms, nose, and eyes placement
- Are responsible for segmentation structures in the body plan
blastocysts
human embryo
- trophoblast
- inner cell mass (ICM), also known for embryoblast
Trophoblast
there on the exterior and give rise to the placenta (chorion)
- implantation: when the embryo is implanted in the endometrium of the uterus
- produces H.C.G (Human chorionic gonadotropin)
implantation
When the embryo is implanted in the endometrium of the uterus
Zona hatching
When the process which the embryo is free of the zona pellucida, exposing the trophoblast layer is exposed
- the embryo is being implanted in the uterus, causing implantation
Human chorionic gonadotropin
A hormone that signals the corpus lignum to continue to produce estrogen and progesterone
- the hormones contain endometrium; if this didn’t happen, then the menstrual cycle doesn’t take place.
ICM (inner cell mass)
- give rise to the embryo blast, amnion, yolk sac, allantois
-distinct cell lineages: epiblast and hypoblast (looks like two pancakes)
Epiblast
outer part
- produces a cavity which is filled with amnionic fluid
- acts like a cushion for the developing embryo
hypoblast
inner part
primitive groove
The dip/inner section/crack from the primitive streak.
eblast cells are going to detach and lost their cell adhesion and go through that primitive streak into the Primitive groove
Mesenchyme
Differentiated and migratory cells that travel through and pop out the other side
Gray crescent
Where the sperm entered and fused with the egg
- mixes the yolk and the animal pole, which makes it grey
- in frogs
Blastopores in frogs
- they do not have primitive streaks, instead cells invaginate through the dorsal lip to form the blastopore
yolk plug
formed from the endoderm cells
- grows into the blastopore and is exposed in the ventral lip of the embryo
Chalaza
anchors the yolk on both ends of the egg shell to help keep in place
Albumen
egg white (helps as a cushion
allantois
the waste sac area when during development
- in placental mammals, it goes to the placenta
