Development Flashcards
Development
modification of structure and physiological characters from fertilization to mature
how does cell and tissue become diverse?
due to cell differentiate
what is cell differentiate?
change in gene expression
3 periods of human embryo
- pre-embryonic period
- embryonic period
- fetal period
pre-embryonic period
first two weeks after fertilization of egg
embryonic period
– Third through eighth weeks
– All major organ systems begin to
develop
fetal period
– Ninth through thirty-eighth weeks
– Growth and development
continues
– Ends at birth
fertilization
fusion of two haploid gametes
(each 23 chromosomes)
what are the gametes involve in fertilization?
secondary oocyte and sperm
zygote
diploid cell with 46 chromosomes
which gamete is bigger?
Oocyte is 2000 times larger than sperm
Fertilization occurs in uterine
tube within _________ of ovulation
a day
what does head of spermatozoon contain?
nucleus and chromosomes
acrosome
a compartment at tip of head
what structure of sperm contain enzyme essential to fertilize?
acrosome
neck of sperm
contain centrioles
middle piece of sperm
mitochondria and microtubules
tail of sperm
only flagellum in human body
which stage does secondary oocyte leave follicle?
metaphase of meiosis II
Cells of the ________ __________ surround the oocyte
corona radiata
what event must happen to cause fertilization?
sperm must penetrate the corona radiata
The sperm binds receptors in
the ______ _________ beneath
corona radiata
zona pellucida
role of acrosomal enzymes
create gap in corona radiata (sperm can go thru)
Oocyte activation
Fusion between sperm and oocyte membranes
Enzymes inactivate sperm receptors and harden the
______ ______________
zona pellucida
how many sperm fertilizes?
only one
Dad’s contribution
23 chromosomes, 1 centriole, and
determines sex
what happen during pre embryonic period
amphimixis, zygote cleavage, and differentiation
Amphimixis
the male and female pronuclei (1n+1n) fuse
what happen after amphimixis?
zygote begin cleavage ( a series of cell division)
As the zygote divides, cells have differing _________ __________
cytoplasmic
compositions
gestation
time spent in prenatal development
what are the phases of gestation?
- first trimester
- second trimester
- third trimester
(each trimester is 3 months long)
first trimester
- Period of embryological and early fetal development
- Rudiments of all major organ systems appear
second trimester
- Development of organs and organ systems
- Body shape and proportions change
third trimester
- Rapid fetal growth and deposition of adipose tissue
- Most major organ systems are fully functional
4 major stages of first trimester
- cleavage (zygote -> blastocyst)
- implantation
- placentation -> placenta develops
- embryogenesis
which trimester is the most dangerous in prenatal life?
first trimester
The cells produced by cleavage divisions are called _________
blastomeres
3 days of cleavage, the pre-embryo is a solid ball of cells, which is called:
morula
The cells of the morula reorganize into a hollow ball called ______
blastocyst
what is the inner cavity of blastocyst called?
blastocoele
blastomeres then form ________ and _______
trophoblast and inner cell mass
trophoblast
outer layer facilitates nutrient exchange
inner cell mass
cells that will form the embryo
