Embryology Flashcards
What are the four adjectives relating to the directions of an embryo?
Ventral
Dorsal
Caudal
Cranial
What is the embryonic period?
Fertilisation to end of week 8
What is the foetal period?
Week 9 to birth
What is ectopic implantation?
Implantation of the foetus outside of the uterus
What are the two versions of the embryo in week 1?
Morula
Blastocyst
What are the two layers of the bilaminar embryonic disc?
Epiblast
Hypoblast
What forms from the epiblast?
Amnion
What forms from the hypoblast?
Umbilical vesicle - yolk sac
What usually happens when there are developmental anomalies within the first 2 weeks of development?
Spontaneous abortion
What is gastrulation?
Formation of 3 definitive germ layers
What is teratology?
Study pf developmental anomalies, birth defects and their causes
What are the four problems that may occur during development?
Malformation
Deformation
Dysplasia
Disruption
What is a malformation?
Morphologic defect of an organ or larger body region
What may a malformation result in?
Anomalies in cell differentiation, migration, proliferation and death
What are some examples of malformations?
Congenital heart defect
Hemivertebrae
What is a deformation?
Abnormal shape or position of a body resulting from mechanical forces
What system is usually involved in a deformation?
Musculoskeletal system
What is a disruption?
Morphological defect of an organ or a larger body region resulting from external breakdown or interference with the normal developmental process
What is a dysplasia?
Abnormal organisation of cells in tissues and its morphological results
What are the four possible patterns of defects?
Sequence
Syndrome
Field defect
Association
What is a sequence?
Cascade of defects arising from a single known or presumed structural defect or mechanical factor
Name two sequences.
Pierre robin sequence
Potter sequence
What is a syndrome?
Multiple defects that occur together in a predictable way
What is a field defect?
Multiple anomalies in the same developmental region
What is an association?
Non-random, pathogenically unrelated, multiple defects
When is an association diagnosed?
If it doesn’t fit under the umbrellas of field defect, syndrome or sequence
What are the two layers that the trophoblast proliferates into?
Cytotrophoblast - faces inward toward uterine cavity
Synctiotrophoblast - Digests the uterine matrix
What are the three parts of the trophoblast?
Cytotrophoblast - White circles
Synctiotrophoblast - outermost, green
Trophoblastic lacuna - red part
What are the name of the two embryonic cavities?
Amniotic cavity
Yolk sac cavity
What is the name of the cavity in the centre of the embryo?
Chorionic cavity
What are congenital defects?
Depending on mutations, teratogen, exposure, timing, a number of anomalies
What are the 4 congenital defects?
Reduction defects
Duplication defects
Dysplasia
Defomations
What term is used for the absence of hands?
Acheiria
What term is used for the absence of feet?
Apodia
What term is used for the absence of both hands and feet?
Acheriopodia
What term is used for the absence of all the digits on a limb?
Adactyly
What term is used for the complete absence of one or more limbs?
Amelia
Ectromelia
What term is used for elongated digits?
Arachnodactyly
What term is used for shortened digits?
Brachydactyly
What term is used for flexion contracture of a finger (often fourth or fifth), which cannot be fully extended?
Camptodactyly
What term is used for the curving of the fifth finger toward the fourth?
Clinodactyly
What term is used for the absence of the pre or postaxial structure of a limb?
Hemimelia
What term is used for the absence of a limb?
Meromelia
What term is used for the absence of any number of fingers or toes?
Oligodactyly
What term is used for the absence of proximal limb structures?
Phocomelia
What term is used for the presence of extra digits or parts of digits?
Polydactyly
What term is used for the absence of the central components of the hand or foot?
Slit hand or foot
What term is used for the fusion of digits?
Syndactyly
What term is used for the fusion of bones and intervening soft tissue?
Synostosis
What term is used for a thumb with 3 rather than 2 phalanges?
Triphalangeal thumb
