Embryology Flashcards
What is a gamete
sperm or egg
When does an embryo exist
between 3 and eight weeks
When does a foetus exist
between 9-40 weeks
Teratogen
an agent that can cause abnormalities
what are example effects of teratogens (3)
malformations
Disruption
Deformation
Malformations (2)
complete/partial absence of a structure
Alterations in a structures normal configuration
Disruption (2)
alterations of already formed structures
Caused by destructive processes
Deformation
abnormal form due to mechanical factors over a prolonged period
What are the phases of embryogenesis (6)
gametogenesis
Fertilisation
Cleavage
Gastrulation
Morphogenetic
Organogenesis
Gametogenesis
formation of a gamete from primordial germ cells
Fertilisation
fusion of sperm and oocyte
Cleavage
rapid cell division with no increase in size
Gastrulation
establishment of three germ layers
What are the three germ layers
endoderm
Mesoderm
Ectoderm
Morphogenesis
Folding of cranial and lateral regions
Followed by folding of the caudal region
Major processes occurring during embryonic development (2)
primary and secondary
Primary developmental processes (6)
division
Apoptosis
Differentiation
Attachment
Induction
Migration
Secondary developmental processes (3)
polarity
Folding/rotation
Change in size and dimension
Dorsal
posteriori
Ventral
anterior
Where does fertilisation take place
Ampulla
Steps of fertilisation (5)
sperm binds with zona pellucida
Release of acrosomal enzymes
Sperm digests into egg
Membranes of sperm and egg fuse
Sperm entry triggers completion of meiosis 2
Describe stages of human development
Zygote - blastomere - morula - blastocyst
What are the components of a blastocyst (3)
blastocoele (cavity)
Embryoblast (inner cell mass)
Trophoblast (outer cell mass)
Where does implantation normally occur
endometrium/uterus
What is the first evidence of gastrulation
formation of the primitive streak
Where is the primitive streak found d
Mid line of caudal region of embryo
Notochord
cellular rod along longitudinal axis
Why is the notochord important (3)
Support
Signalling
Becomes nucleus pulposus
Derivatives of endoderm (3)
lining of gut
Lining of respiratory tract
Lining of bladder and urethra
Derivatives of ectoderm (2)
hair, nails etc
Nervous system
Derivatives of mesoderm (4)
Circulatory system
Lungs
Skeletal system
Muscular system
