pre-embryonic
structures are in the head of sperm
Nucleus covered by acrosome
What are the 2 parts blastomeres become?
embryoblast & trophoblast
(blastocyst stage)
What makes up embryonic disk?
Ectoderm: Mesoderm: Endoderm:
(Be able to recognize the 3 germ layers)
Ectoderm: becomes epidermis, hair, nails and nervous system
Mesoderm: muscle, skeleton, dermis, connective tissue, urogenital glands, blood vessels, blood and lymph
Endoderm: epithelial lining of digestive, respiratory and urinary systems, glandular cells of organs i.e. liver pancreasFetal age range when Quickening may be sensed, Eye movement starts, Responds to sound
wks 15-18GA /13-16FA
heartbeat be detected by vaginal U/S?
as early as 6 weeks, but may need to be repeated. Constistently by 8 wk
biparental inheritance,
offspring inherit genetic material from both parents (a chromosome from each parent)
what the zona pellucida does.
a protective shell that surrounds the oocyte (immature egg)
facilitates sperm binding and the acrosome reaction, and blocks other sperm from binding to the fertilized egg.
organize the order of the pre-embryo to embryonic development from the following terms: morula, blastocyst, zygote, embryo
zygote, morula, blastocyst, embryo
when eyebrows and head hair begin to appear.
present by 22 weeks into pregnancy/20 weeks after conception; hair follicles start week 14,
bones become visible on U/S
as early as 9 weeks, and most by 12 weeks
what decidual reaction
The uterine lining responds to the embedding fetus to produce decidua stroma endometrial cells to support the pregnancy, accompanies implantation, supported by progesterone from the ovaries and human Chorionic Gonadotropin (hCG), a hormone produced by the embryo after implantation, is crucial for this process
Define cleavage.
Repeated mitotic divisions of the zygote
The ectoderm of the neural plate give rise to the
brain, spinal cord and various other structures of the nervous sytem
heart begin to beat
end of the third week (day 21-22); Heart pumps blood 24-28 day
Preterm fetal survival depends on adequate development of what 2 systems?
circulatory and respiratory
where fertilization takes place.
ampulla of the fallopian tube
compaction (pre-embryo)
Compaction in a morula = The basis of embryoblast formation due to cell to cell interaction (the individual cells (blastomeres) flatten and adhere tightly to one another, losing their individual boundaries)
during this embryonic week: Oral and nasal cavities and upper lip formed;
auditory systems forming; Liver begins to form blood cells
wk 8GA/ 6FA
In early embryonic development, the trophoblast layer of the blastocyst differentiates to form both ___ and ____ membranes
amnion and chorion sac.
what is surfactant and what time frame does it start to be secreted
lipids and proteins mixture secreted by the lung starting around 24week GA, however, not in sufficient amounts until around 35weeks.
reduce surface tension at the air-liquid interface within the alveoli (tiny air sacs in the lungs), preventing them from collapsing during exhalation
what is ectopic pregnancy, where does it usually occur = the accompanying symptoms
pre-embryo embeds outside the uterus, usually in the fallopian tube = bleeding, tenderness, severe pain on one side
Most common cause of SAB and Estimated rate of SABs
Chromosomal abnormalities; between 10% and 20% but up to 30%
digital rays begin to develop
6 weeks after conception (finish end of week 8)
what is the difffernce between lanugo and vernix
lanugo; fine downy hair all over the fetus; appears wks 19-22GA/ 17-20FA; dissapears near or after term
fat, waxy white substance to protect the skin; develops wks 19-22GA/ 17-20FA, dissappears near term
what fetal age range for the Hiccups, suck and grasp reflex
9-22GA/ 17-20FA