Slide 1
Stages of human developmentprenatalinfancybabyhoodByAngelica L.
AndayaGemma VillanuevaPrenatal PeriodFrom Conception to Birth
Prenatal DevelopmentFrom conception to birthProceeds according
to a genetic blueprint that directs the construction of an
extremely complex being from what starts out as only single cell
(zygote)Three stagesGerminal stageEmbryonic stageFetal stage
Germinal StageFertilization to two weeks (implantation)During
this stage, the organism divides, become more complex and is
implanted in the wall of the uterus.
The blastocyst is made up of three layers:
A. Ectodermthe outermost of the three germ layers, or masses of
cells, which appears early in the development of an animalembryo
gives rise to hair, skin, nails or hooves, and the lens of the eye;
the epithelia (surface, or lining, tissues) of sense organs, the
nasal cavity, the sinuses, the mouth (includingtoothenamel), and
the anal canal; and nervous tissue, including the pituitary body
and chromaffin tissue (clumps of endocrine cells)B. Mesodermthe
middle of the three germ layers, or masses of cells (lying between
the ectodermand endoderm), which appears early in the development
of an animalembryo. gives rise tomuscle,connective
tissue,cartilage,bone,notochord,blood, bone marrow, lymphoid
tissue, and to the epithelia (surface, or lining, tissues) of blood
vessels, lymphatic vessels, body cavities, kidneys, ureters, gonads
(sex organs), genital ducts, adrenal cortex, and certain other
tissues.
C. Endodermthe innermost of the three germ layers, or masses of
cells (lying withinectoderm and mesoderm), which appears early in
the development of ananimalembryo. gives rise to
theepithelium(tissue that covers, or lines, a structure) of the
pharynx, including the eustachian tube, the tonsils, thethyroid
gland, parathyroid glands, and thymusgland; the larynx, trachea,
and lungs; the gastrointestinal tract (exceptmouthand anus),
theurinary bladder, the vagina (in females), and theurethra.
Embryonic Stage Two to 8-12 weeksa time when the mass of cells,
embryo becomes a distinct human being. Cells continue to rapidly
divide and clusters of cells begin to take on different functions
(called differentiation)Most vulnerable to prenatal environmental
influencesAlmost all of the developmental birth defects occurred
such as cleft palate, incomplete or missing limbs, blindness,
deafness
Fetal Stage8-12 weeks to birthDuring the long period until
birth, the finishing touches are put on the various parts, and the
body changes in formGrows about 20 times lengthFetus kicks, turns,
flexes its body, somersaults, squints, swallows, makes fist,
hiccups, and sucks its thumbResponds to both sound and
vibration
Infancy from birth to the end of the second week
THANK YOU!!
