Lecture 4- Embryology Flashcards
How does the medical model view disability
As a deficiency or abnormality
What is the remedy of disability according to the medical model
Cure or normalization of the individual
How does the social model view disability
As being different
According to the social model how is disability remedied
By making society become more accessible to the individual
According to the social model what does disability derive from?
From the interaction of the individual with society
According to the medical model what does disability derive from?
The individual’s physical or mental limitations
Atypical bodies don’t always require _______
Treatment or cure
What are the 3 stages of prenatal embryology
Pre-embryonic, embryonic, fetal
What is the timeframe of the pre-embryonic stage?
1-2 weeks
What is the timeframe of the embryonic stage?
3-8 weeks
What is the timeframe of the fetal stage?
9-38 weeks
What age do clinicians use
Gestational age
When is gestational timed from
The last normal menstrual period
Gestational age in weeks =’s ____________ age in weeks +2
Embryonic
What are the major events of the pre-embryonic stage
Fertilization, blastocyst (formation of and implantation of), bilaminar disc
What happens in the embryonic stage?
Gastrulation, neurulation, body folding, origin of organ systems
What what happens in the fetal stage?
Rapid growth, maturation of tissues and organs
What is a teratogen
Genetic/ environmental agent that alters the development of the embryo/ fetus
When is the greatest risk of of developing a congenital difference
The embryonic period
A teratogen in the pre-embryonic period will cause what
A spontaneous abortion
Superior direction in an adult is _____ in an embryo
Cranial (cephalic)
Inferior direction in an adult is _____ in an embryo
Caudal
What 3 things happen in week 1 of the pre-embryonic stage
Fertilization, blastocyst, implantation
What happens in week 2 of the pre-embryonic stage
Bilaminar disc
Fertilization is the union of what
Gametes (sperm & ovum)
Where is the normal site of implantation
Ampulla of fallopian tube
After the sperm nucleus enters the cytoplasm of the oocyte what is formed
The zygote
Familiarize yourself
Implantations that occur in the abdominal cavity commonly occur where
In the rectouterine pouch
Identify arrows
What are the 2 steps of IVF
▪ Oocytes collected via laparoscopy and placed in culture dish
▪ Sperm added immediately
What are the 2 steps in intracytoplasmic sperm injection
▪ Oocytes collected like in IVF
▪ A single sperm is injected into oocyte (circumvents male infertility)
ARTs are associated with 30-40% risk of what
Spontaneous abortions, multiple births, low birth weight, preterm delivery
During week 1 what do cleavage and compaction achieve
Cleavage: Increases cell number without increasing mass (cells get smaller)
Compaction
Compaction forms what 2 things in week 1
An outer cell mass and an inner cell mass
Cleavage of week one ends with what
Formation of a blastocyst
Define blastocyst
Morula with a fluid-filled cavity
What is the outer cell mass called in week 1&2
Trophoblast
What is the inner cell mass called in week 1
Embryoblast
What are the arrows pointing to
The blastocyst hatches from _____ to allow implantation
Zona pellucida
Day 6: where does the initial implantation of the blastocyst occur
Week 2- What are the 2 things that the trophoblast develops into?
Syncytiotrophoblast, cytotrophoblast
Week 2- What are the 2 things that the Embryoblast develops into?
Epiblast, hypoblast
A morula is composed of how many cells
16
What is the order of naming the baby in the first week
Blastomere–> morula–>blastocyst
Week 2- What are the 2 cavities formed by the epiblast & hypoblast?
Amniotic cavity, chorionic cavity
Week 2- What are the 2 things that the extra-embryonic mesoderm develops into by the chorionic cavity splitting?
Parietal layer, visceral layer
Appearance at the end of week 2- identify arrows coming from the top
Appearance at the end of week 2- identify arrows coming from the right
Appearance at the end of week 2- identify arrows coming from the bottom
What happens in week 2
The completion of implantation
The hole in the uterine mucosa heals by when
Day 13- the blastocyst is now within the uterine mucosa
Week 2- The trophoblast part of blastocyst continues to erode into endometrium and will eventually establish _______________
Uteroplacental circulation
What does the syncytiotrophoblast do
Acts as a barrier between the fetal and moms blood
What does the syncytiotrophoblast secrete in week 2
Human chorionic gonadotropin (HcG-maintains corpus luteum), Progesterone
What does the cytotrophoblast act as
Stem cell reserve
What erodes the uterine epithelium during implantation
Syncytiotrophoblast
What are the derivatives of the epiblast?
Body of the embryo, amniotic sac
What are the derivatives of the hypoblast?
Yolk sac (replaces blastocyst), extra embryonic mesoderm
What causes the embryoblast to differentiate into the epiblast and the hypoblast
Fibroblast growth factor (FGF)
When viewed dorsally the epiblast and the hypoblast form what
Bilaminar disc
The amniotic cavity forms the _____
Epiblast
The chorionic cavity forms between the yolk sac and cytotrophoblast from a new tissue layer called the ________
Extra embryonic mesoderm
What lines the yolk sac
Visceral EEM (gives rise to initial blood cells & vessels in week 3)
Formation of the chorionic cavity splits the extra-embryonic mesoderm into what 2 layers
Parietal, visceral
Gastrulation happens in what weeks
3-4 (cranial end finishes before caudal end)
Gastrulation begins with what
The appearance of the primitive streak on the epiblast
Gastrulation does what
Forms 3 germ layers
What are the 3 germ layers that gastrulation gives rise to
Ectoderm, mesoderm, endoderm
What forms at the head end of the primitive streak?
Primitive node
The primitive node secretes what
Fibroblast growth factor 8 (FGF8)
What does fibroblast growth factor 8 control
The cell migration of epiblast cells
Along the midline, a solid cord of cells differentiates into the _____
Notochord
What are the 3 functions of the notochord- to signal the formation of the….
Midline axis of the embryo, axial skeleton, neural tube
FGF8 causes the epiblast cells to do what
Invaginate at the primitive node and migrate cranially
Invaginating epiblast cells that replace hypoblast cells differentiate into _____
Endoderm
Invaginating epiblast cells that stay between endoderm & epiblast differentiate into ______
Mesoderm
Epiblast cells that remain on the surface differentiate into _______
Ectoderm
Ectoderm gives rise to what
Tissues & organs that maintain contact with external environment (e.g., epidermis, central nervous system, peripheral nervous system, neural crest cells)
Mesoderm gives rise to what
Connective tissues, muscle, vascular & urogenital systems
Endoderm gives rise to what
Endoderm gives rise to epithelial lining of digestive & respiratory systems, bladder & urethra; parenchyma of various glands
What can develop from uncontrolled growth of pluripotent embryoblast cells
Teratoma (germ cell tumor)
What is a totipotent cell derived from & what can it form into
Derived from zygote or blastocyst; can form any cell or tissue type
What is a pluripotent (AKA embryonic stem cell) cell derived from & what can it form into
Derived from embryoblast; can form any of three germ layers and derivatives
What is a multipotent (progenitor cell) cell derived from & what can it form into
Found in red marrow and embryo and adult; can form a few cell types (e.g., hemopoietic progenitor cell forming different types of adult blood cells)
What is a unipotent (precursor cell) cell derived from & what can it form into
Found in embryo and adult; can form a single cell type
What is a summary of week 1
What is a summary of week 2
What is a summary of weeks 1-3
High levels of HcG in urine indicate what
A successful implantation has occurred
The extra-embryonic mesoderm lines what cavity
Chorionic cavity
Gastrulation establishes what
Tissue lineages
