Intro Flashcards
The period of gestation that is prior to birth
Prenatal period
22 weeks gestation to 28 days after birth
Perinatal period
Up to 1 month after birth
Neonatal period
First Postnatal year
infancy
12 months to 12-13 years
Childhood
10-15 years (girls) 12-17 years (boys)
Puberty
3-4 years post puberty
Adolescence
From 18-25 years to…
Adulthood
What is the estimated pregnancy length
281 days with a standard deviation of 13 days
What occurs in week 1
Preimplantation stage: zygote, morula, blastocyst
What occurs in week 2
Inner cell mass forms bilaminar embryo
What occurs in week 3
Bilaminar embryo becomes trilaminar embryo
What occurs in weeks 3-8
Embryonic period - organogenesis
What occurs in week 9 to term
Fetal period - growth and differentiation
The age of the conceptus from the presumed first day of the last menstrual period
Gestational age (GA)
The age of the conceptus from the fertilization day
Fertilization age
GA is approximately _ weeks longer than the fertilization age because…
2; the oocyte is not fertilized until about 2 weeks after LMP (Last menstrual period)
What is naegele’s rule for EDD?
First day of the LMP subtract 3 months, then add one year and one week
Expulsion from the uterus of conceptus prior to the age of viability (22-23 weeks) or conceptus weight
Abortion
Spontaneous expulsion from the uterus of conceptus relatively early (
Miscarriage
The majority of miscarriages are caused by
Chromosomal abnormalities
Infants born between stage of viability and 37 weeks
Premature birth
Majority of premature births caused by
maternal complications of the pregnancy
The first 2 weeks of development known as the
All or nothing period
What stage is the most vulnerable to teratogenic agents
Embryonic stage (critical period)
During what period is an injury most likely to produce minor structural defects or functional abnormalities.
Fetal period
These are identified during the 4th week in the yolk sac
Primordial germ cells
In weeks 4-6 PGCs
migrate to the future genital ridge area
PGCs stimulate the surrounding epithelium to create the
somatic support cells -> swelling = primitive gonad
After PGCs stimulate the surrounding epithelium they are now called
gonocytes
Somatic support cells become
Ovarian follicles (female) and Sertoli cells (male)
Gamete maturation is called _ in males and _ in females
spermatogenesis; oogenesis
Agonies that survive are arrested in
meiosis I
Primary oocytes don’t form after _ and remain dormant until _
birth; puberty and then one is released each month
Shortly before ovulation, primary oocytes undergo
the first meiotic division which forms a haploid secondary oocyte and the first polar body
A polar body is a
small, nonfunctional cell
At ovulation the secondary oocyte enters _ and progresses to _
the second meiotic division; metaphase and is then arrested
The second meiotic division of the secondary oocyte is only completed if
fertilization occurs
By birth, females have about _ primary oocytes and by puberty have
700,000; 400,000
Spermatogonia’s inside the embryonic male gonad remain dormant from
the 6th week until puberty
Spermatogenesis takes place continuously from
puberty until death (200-300 million sperms/day)
The entire spermatogenesis process takes about
2 months
At puberty, Sertoli cells differentiate into
seminiferous tubules
Spermatogenesis takes place in the
luminal side of the seminiferous epithelium
Primary spermatocytes are
diploid
2 secondary spermatocytes become
4 spermatids
Spermatids become mature sperm while
completing their migration to the lumen
What is the process of sperm cell differentiation called
spermiogenesis
Name the 4 anatomical embryological planes
Median (longitudinal), Sagittal (parallel to the median plane), Transverse (axial) (perpendicular on both median and coronal), Frontal (coronal) (perpendicular on the median plane).
