DEVELOPMENT & AGING (2) Flashcards Preview

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Flashcards in DEVELOPMENT & AGING (2) Deck (17):
1

ovulation

ovaries release eggs (erupt) once a month
-birth control and being pregnant stops it from cycling

2

zygote

fertilized egg and sperm

3

embryo

implanted zygote (pregnant)

4

fetus

after 3 months embryo turns into this

5

cleavage

zygote divides into 2 cells, then 4, then 8, then 16, and 32 cells

6

growth

cells increase in size

7

morphogenesis

cells move or migrate to shape the embryo

8

differentiation

cells take on specific structure and function

9

extraembryonic membranes

1. chorion
-develops in the fetal half of the endometrium (placenta)
2. yolk sac
-little yolk and is the the first site of RBC formation
3. allantosis
-gives rise to the bladder; the allantosis blood vessels become the umbilical blood vessels
4. amnion
-contains amniotic fluid to cushion and protect the embryo

10

pre-embryonic

encompasses the events of first week of development after fertilization
-cleavage
-morula
-blastocyst
-implantation

11

cleavage

cell division that increases the number of cells

12

morula

solid mass of cells
(a zygote that is cleaving)

13

blastocyst

inner cell mass becomes the embryo surrounded by the trophoblast that becomes the chorion

14

implantation

usually occurs on the 6th day

15

embryonic development

begins in the 2nd week and lasts until the end of the 2nd month of development
-pregnancy begins after implantation
-nervous system becomes evident
-heart begins development the 3rd week and begins beating the 4th week
-all organ systems have been established by the end of this development stage

16

fetal development

includes the 3rd thru the 9th months of development
-fetus has visible human characteristics
-cartilage begins to be replaced by bone
-3rd month can distinguish sex of it
-4th month heartbeat is loud enough to hear with a stethoscope
-5th-7th month fetal movement can be felt, fetal position, eyelids can open
-fetus is about 201/2 in long and weighs about 71/2 pounds at the end of this stage of development

17

stages of life

-infancy
-childhood
-adolescence
-adulthood