ch 29 development pt 1 Flashcards
development
gradual modification of anatomical structures and physiological characteristics from fertilization to maturity
prenatal development
embryonic and fetal development stages
postnatal development
from birth to maturity
maturity
state of full development or completed growth
pre-embryonic development
processes that occur in the first 2 weeks after fertilization
embryology
study of the development of the embryo
fetal development
processes that occur in the development of a fetus, between the 9th week and birth
cellular differentiation
process of cell specialization which created different types of cells
inheritance/heredity
transfer of genetically determined characteristics from generation to generation
genetics
study of the mechanisms responsible for inheritance
fertilization
fusion of sperm to ovum, each containing 23 chromosomes
- produces zygote w/ 46 chromosomes
what stage is the ovum in when fertilization occurs
secondary oocyte
what surrounds the outside of the oocyte
corona radiata - protective layer of follicle cells
zona pellucida - outer layer of ovum, beneath corona radiata
what phase is secondary oocyte suspended in before fertilization
metaphase 2 of meisosis
steps of fertilization (5)
- oocyte at ovulation
- fertilization and oocyte activation (acrosomal enzymes create gaps in corona radiate)
- pronuclei develop and DNA synthesis occurs (sperm absorbed in cytoplasm, female pronucleus develops)
- spindle formation begins
- amphimixis occurs and cleavage begins (maternal and paternal chromosomes align on metaphase plate)
- 1st cleavage forms 2 blastomeres
gestation
time spent in prenatal development
1st trimester characteristics
pre-embryonic to month 3
has 4 processes: cleavage/fertilization, implantation, placentation, embryogenesis
amphimixis
fusion of female pronucleus and male pronucleus. combining to make 46 chromosomes
cleavage
sequence of cell divisions that begins immediately after fertilization
- results in 2 cells each called a blastomere
morula
blastomeres organized into a solid ball of nearly identical cells on the 3rd day
blastocyst
on day 6, the morula enters the uterus and becomes a blastocyst, a hollow ball of cells with an internal cavity called the blastocoele
implantation
blastocyst attaches to the endometrium of uterus
- begins on day 7 or 8
what cells make up the outside of a blastocyst
trophoblasts
cytotrophoblast
cells closest to the inner cell mass
syncytiotrophoblast
outer layer which erodes a path through the uterine epithelium by secreting hyaluronidase
placentation
the placenta develops to permit the exchange between maternal and embryonic blood
embryonic period
from implantation to week 9
2nd trimester characteristics
articulations begin to form
fetus doubles in size
3rd trimester characteristics
functional organ systems
fetus responds to sensory stimuli
gastrulation
cell migration in the early embryo that results in the formation of an embryonic disc
3 germ layers of gastrulation
ectoderm
mesoderm
endoderm
ectoderm contributions (ISNERD)
Integumentary: epidermis, hair, nails
Skeletal: pharyngeal cartilages, styloid processes
Nervous: all neural tissue including brain and spinal cord
Endocrine: pituitary gland and adrenal medulla
Respiratory: mucous epithelium of nasal passageway
Digestive: mucous epithelium of mouth and anus; salivary glands
mesoderm contributions (ISME)
I: dermis and hypodermis
Skeletal: all skeletal structures
Muscular: all structures of muscular, cardiovascular and lymphatic systems
Endocrine; adrenal cortex and endocrine tissues of heart, kidnets
mesoderm contributions (CLURM)
Cardiovascular: all structures
Lymphatic: all structures
Urinary: kidneys
Reproductive: gonads
Miscallaneous: pleura linings
ENDOderm contributions (ERDUR)
Endocrine: thymus, thyroid gland + pancreas
Respiratory: respiratory epithelium except nasal passageways
Digestive: mucous epithelium, exocrine glands (except salivary), liver
Urinary: urinary bladder
Reproductive: stem cells that produce gametes + distal portions of duct system
the 4 extra embryonic membrane
yolk sac
amnion
allantois
chorion
body stalk
connection between embryo and chorion
yolk stalk
narrow connection between endoderm of embryo and yolk sac
The trophoblast will eventually become part of the
placenta
What stage of preembryonic development results in a solid ball of nearly identical cells?
morula
Cells of the epiblast move toward the medial plane of the blastodisc to a region known as the
primitive streak
The placenta is made up of a contribution from mother and fetus. Which portion is from the fetus?
chorion
