Section 4: Prenatal Development and Birth Flashcards
Periods of prenatal period:
Germinal
Embryonic
Fetal
Germinal period is
begins when the mother’s and father’s germ cells are joined at conception, and lasts until the developing organisms becomes attached to the wall of the uterus, about 8-10 days later
includes cleavage and implantation
cleavage is
zygote divides by mitosis into two cells, which then also divide, and so on
heterochrony
different parts of the organism develop at different rates is called
heterogeneity
variability in the levels of development of different parts of the organism at a given time
totipotent stem cells are when
each cell has the potential to grow into an embryo, and, ultimately, a normal, healthy baby
multipotent stem cells are when
the cell can become different types of cells, but not any type of cell
Adult stem cells are ____ stem cells
multipotent
Implantation is
process by which organism becomes attached to the uterus
a. Developing cell mass moves further into the uterus
b. Outer cells put out tiny branches that burrow into the spongy wall of the uterus until they come in contact with the mother’s blood vessels
Embryonic period is
extends from the time the organism becomes attached to the uterus until the end of the 8th week
- All the major organs take primitive shape
- Organism begins to respond to direct stimulation
- Period of rapid growth
- Development of Placenta, Amnion, Amniotic fluid, and Chorion: Sources of Nutrition and Protection
Amnion is
thin, tough transparent membrane that holds amniotic fluid
Early in development, surrounds the embryo
Amniotic fluid is
- Cushions the organism
- Provides liquid support for its bones and muscles
- Gives it a medium in which it can move and change position
(In the amnion)
Chorion is
membrane that surrounds the amnion
Later becomes the fetal component of the placenta
Placenta is
complex organ made up of tissue from both the mother and the embryo
a. Barrier that prevents the bloodstreams of the mother and the infant from coming into direct contact
b. Filter that allows nutrients and oxygen to be exchanged
c. Converts nutrients carried by mother’s blood into food for the embryo
d. Enables the embryo’s waste products to be absorbed by the mother’s bloodstream
The separation of inner cell mass into two layers occurs in what prenatal period?
Embryonic
The ectoderm is
- Outer layer
- Gives rise to the outer surface of the skin, the nails, part of the teeth, the lens of the eye, the inner ear, and the nervous system
The endoderm is
- Inner layer
2. Develops into the digestive system and lungs
The mesoderm is
- Middle layer
- Becomes the muscles, bones, circulatory system, and the inner layers of the skin
Forms after ectoderm and endoderm
Epigenesis is
idea that each new phenotypic form emerges as a result of the interactions that take place between the preceding form and its environment
Two patterns of body development that are maintained until the organism reaches adolescence
i. Cephalocaudal pattern
ii. Proximodistal pattern
Cephalocaudal pattern is when
development proceeds from the head down
Proximodistal pattern is when
development proceeds from the middle of the orgnism out to the periphery
No structural differentiation for first _____
six weeks
gonadal ridge is
ridge of tissue from which the sex organs will develop
Androgens are
- Produced by male gonads
2. Male hormones, including testosterone
Fetal period is
begins the 9th week after conception, with the first signs of the hardening of the bones, and continues until birth.
- Primitive organ systems develop to the point where the baby can exist outside the mother without medical support
- Ossification
- Fetus increases in length and in weight dramatically
- Organ systems increase in complexity
Ossification is when
tissue that will become the skeleton begins to harden
disease of spinal cord and backbone
Spina bifida
disease of the brain and skull
Anencephaly
Teratogens are
Environmental agents that increase risk of deviations in normal development and can lead to serious abnormalities or death
In Stage 1 of labor
a. Uterine contractions of sufficient frequency, intensity, and duration begin to cause the cervix to dilate
b. Continues until the opening of the uterus into the vagina is fully dilated and the connections between the bones of the mother’s pelvis become more flexible
In Stage 2 of labor
a. Begins as baby is pushed headfirst through the fully dilated cervix into the vagina
b. Contractions now no more than a minute apart and last about a minute
c. Pressure of the baby in the birth canal and the powerful contractions of the uterus cause the mother to bear down and push the baby out
In Stage 3 of labor
a. Baby has emerged from the vagina
b. Uterus contracts around its diminished contents
c. Placenta buckles and separates from the uterine wall, pulling the other fetal membranes with it
d. Contractions quickly expel them, and they are delivered as the afterbirth
used to rate babies’ physical condition at 1 minute and again at 5 minutes after birth using five vital signs
Apgar scale
5 signs used in Apgar scale
i. heart rate
ii. respiratory effort
iii. Muscle tone
iv. Reflex responsivity
v. Color
used to rate babies’ behavioral condition after birth
Brazelton Neo-natal Assessment scale
5 signs used in Brazelton Neo-natal Assessment scale
i. Orientation to animate objects
ii. Pull-to-sit
iii. Cuddliness
iv. Defensive movements
v. Self-quieting activity
