04 EMBRYOLOGY Flashcards
It’s the branch of medicine concerned with the study of embryos and their development.
Embryology
The process of growth and development within the womb, in which a single-cell zygote becomes an embryo, a fetus, and then a baby.
Prenatal Development
This ____________ period happens at the 1st week
Preimplantation
The _________________ extends from the beginning of the 2nd week to 8th week; at this time the developing life is known as an embryo. This is also the most critical time in development.
Embryonic Period
The _________ begins with 9th week and lasts until birth.
Fetal Phase
This occurs when the sperm penetrates and fertilizes the ovum
Fertilization
What do you call a fertilized egg?
Zygote
Birth occurs, on average, ____weeks after conception, or ____weeks after the beginning of the last menstrual period (LMP)
38-40 weeks
Fetal development is divided into ________________.
three trimesters of 3 months each
The fertilized egg undergoes a series of rapid divisions that leads to the formation of a ball of cells called the _______________.
Morula
The fertilized egg undergoes a ___________________________that leads to the formation of a ball of cells called the morula.
series of rapid divisions
Mitotic cleavages
Blastomeres
Fluid seeps into the morula, and its cells realign themselves to form a fluid-filled hollow ball, the _____________.
Blastocyst
As the cells multiply, the blastocyst will arrange themselves into two groups, separating into two distinctive masses:
the outer cells will eventually become the placenta, while the inner cells form the embryo.
The blastocyst is made up of three layers, each of which develops into different structures in the body.
Ectoderm: Skin and nervous system
Endoderm: Digestive and respiratory systems
Mesoderm: Muscle and skeletal systems
_______________ are cells forming the outer layer of a blastocyst, which provides nutrients to the embryo, and develops into a large part of the placenta.
Trophoblast
The blastocyst is the early stages of the prenatal development, consisting of an outer cell layer called the _______________and the inner cell mass at one side of the blastocyst called the ______________________.
trophoblast; embryoblast
It is also used for implantation.
Trophoblast
It is the mass of cells inside the blastocyst that will eventually give rise to the definitive structures of the fetus.
Embryoblast
______________occurs when the cells nestle into the uterine lining and rupture tiny blood vessels.
Implantation
T or F: Implantation is always an automatic and sure-fire process.
FALSE
____________ is a process of conversion/differentiation of embryoblast into two-layered disk.
Gastrulation
T or F: When implantation is successful, hormonal changes halt the normal menstrual cycle and cause a whole host of physical changes.
TRUE
The _____________ is a “uniquely thickened portion” of the endoderm that is in contact with ectoderm immediately rostral to the cephalic tip of the notochord.
Prochordal Plate
The floor of the amniotic cavity is formed by ectoderm, and within it a structure called the ___________ develops along the midline.
Primitive Streak
The rostral end of the streak finishes in a small depression called the _____________
Primitive node, or pit.
Primitive Streak forms:
Embryonic Ectoderm
Intraembryonic mesoderm
Endoderm
Primitive Streak differentiates:
Craniocaudal axis of embryo
Cranial & Caudal Ends
Dorsal and Ventral Surface
Right and Left side
_____is first mesodermal tissue to form.
Notochord
During the third week of development the bilaminar embryonic disk is converted to _______________________________________.
A trilaminar disk; endoderm, mesoderm, and ectoderm.
It forms the epithelium that covers the body and gives rise to cell in the nervous system.
Ectoderm
It forms the connective tissue and soft tissues such as bone, muscles and fats
Mesoderm
It forms the gastrointestinal tract and associated structures involved in digestion.
Endoderm
ENDODERM/MESODERM/ECTODERM:
Epidermis of skin and its derivatives (including sweat glands, hair follicles)
Ectoderm
ENDODERM/MESODERM/ECTODERM:
Cornea and lens of eye
Ectoderm
ENDODERM/MESODERM/ECTODERM:
Epithelial lining of mouth and anus
Ectoderm
ENDODERM/MESODERM/ECTODERM:
Nervous system
Ectoderm
ENDODERM/MESODERM/ECTODERM:
Sensory receptors in epidermis
Ectoderm
ENDODERM/MESODERM/ECTODERM:
Adrenal medulla
Ectoderm
ENDODERM/MESODERM/ECTODERM:
Notochord
Mesoderm
ENDODERM/MESODERM/ECTODERM:
Muscular system
Mesoderm
ENDODERM/MESODERM/ECTODERM:
Skeletal system
Mesoderm
ENDODERM/MESODERM/ECTODERM:
Excretory system
Mesoderm
ENDODERM/MESODERM/ECTODERM:
Muscular layer of stomach and intestine
Mesoderm
ENDODERM/MESODERM/ECTODERM: Circulatory and lymphatic systems
Mesoderm
ENDODERM/MESODERM/ECTODERM:
Reproductive system (except germ cells)
Mesoderm
ENDODERM/MESODERM/ECTODERM:
Dermis of skin
Mesoderm
ENDODERM/MESODERM/ECTODERM:
Lining of body cavity
Mesoderm
ENDODERM/MESODERM/ECTODERM:
Adrenal cortex
Mesoderm
ENDODERM/MESODERM/ECTODERM:
Epithelium of pineal and
pituitary glands
Ectoderm
ENDODERM/MESODERM/ECTODERM:
Tooth enamel
Ectoderm
ENDODERM/MESODERM/ECTODERM:
Epithelial lining of digestive tract
Endoderm
ENDODERM/MESODERM/ECTODERM:
Epithelial lining of respiratory system
Endoderm
ENDODERM/MESODERM/ECTODERM:
Lining of urethra, urinary bladder, and reproductive system
Endoderm
ENDODERM/MESODERM/ECTODERM:
Liver
Endoderm
ENDODERM/MESODERM/ECTODERM:
Pancreas
Endoderm
ENDODERM/MESODERM/ECTODERM:
Thymus
Endoderm
ENDODERM/MESODERM/ECTODERM:
Thyroid and parathyroid
glands
Endoderm
Cells of the ectodermal layer divide at the node and migrate between the ectoderm and endoderm to form a solid column that pushes forward in the midline as far as the prochordal plate. Through canalization of this cord of cells, the ______________is formed to support the primitive embryo.
Notochord
The cells that accumulate anterior to the prochordal plate as a result of this migration give rise to the _____________.
Cardiac Plate
During primary neurulation, the original ectoderm is divided into three sets of cells:
(1) the internally positioned neural tube, which will form the brain and spinal cord,
(2) the externally positioned epidermis of the skin, and
(3) the neural crest cells.
The neural folds eventually fuse so that a __________________ separates from ectoderm to form the floor of the amniotic cavity, with mesoderm intervening.
Neural Tube
The __________ forms the early brain and spine.
Neural Tube