Chapter 29
acutal genetic make up relating to a trait
genotype
physical expression of the genotype
phenotype
Punnet square
used to show the possible genes inherited from two parents
any agent or influence tha can cause developmental defect in an embryo or fetus
teratogen
Placenta functions
O2 and nutrients from mom to fetus; CO2 from fetus to mom
Protective barrier
Stores nutrients and release them when fetus is need of them
Trophoblast
blastocyst; develop into the outer chorionic sace surrounding the fetus and the fetal portion of the placenta
embryoblast
blastocyst; develop into the embryo (inner cell mas)
blastocyst
free in pelvic cavity for 2 days then implants itself by attaching to endometrium
day 7-becomes firmly embedded in endometrium; forms new blood vessel; secretes enzymes then burrows into endometrium and comes surrounded by it
Gastrulation
15 days after fertilization; 2 layered embryonic disc turns into 3 layers
ectoderm, mesoderm, endoderm (germ layer)
Gastrulation
Associtated with rearrangement and migration of cells from epiblast with first step being the formation of the primitive streak
gastrulation
Primitive streak
establishes the head and tails end of embryo, as well as right and left sides
Allantois
fucntion is to collect liquid waste from embryo and exchange gases by embryo
Alleles
genes for the same trait that are in the same locatin of each homoloque
Homozygous
a person with the same allele on homologous chromosome for that certain train; ex PP
Heterozygous
a person with different alleles on the chromosome for that certain trait; ex Pp
Dominant allele
dominates or masks the presence of another allele
recessive allele
presence is completely masked
Incompleted dominance
situation where neither member of the pair alleles is dominant over the other
Polygenic inheritance
a trait is controlled by the combined effects of many genes and enviromnetal factors
chromosomes
23 pairs (46); 22 autsomes,; one pair of sex chromosome
Karyotype
an entire set of chromosomes arranged in decreasing size order and according to the portion of the centromere
Breastfeeding
baby's brain development; immunity, antibodies, optimal growth, reduction in several diseases
Milk-ejection reflex
oxytocin stimulates the contraction of cells around structures that produce milk into mammary ducts
down syndrome
three rather than 2 coped of at least a part of chromosome 21 formed
Relaxin
secreted by corpu luteum then later by placenta
increases flexibility of ubic symphysis and helps dilate cerix during labor
relaxin
Lochia
uterince discharge for 2 to 4 wks after delivery that consist of blood and then the serous fluid from former sire of placenta
Corticotropin-releasing hormone
secreted by placenta; needed to increase secretion of cortisol, maturation of fetus's lungs and surfactant
shock absoprtion, regulats body temp, preents drying out, prevent adhesions of skin of surrounding tissues
amniotic fluid functions
Third Trimester
rapid fetal growth, wt of fetus doubles, organ systems fully fuctional
stimulate uterine motility and aid in sperm movement
Prostaglandins in sperm
Glycoprotein ZP3
receptor for the sperm; binding cause ascrosomal reaction which causes ascromosal enzymes to be released to digest a path in zona pellucida
after implanataion, functional layer of endometrium
separates from endometrium after fetus is delivered
decidua
provides glycogen and lipids for embryo/fetus and later becomes maternal part of placenta; part of endometrium beneath implanting embryo
basal decidua
Capsular decidua
covers the embryo after implantation; becomes thin as embryo and fetus enlarge and then degenerates adn disappears around 27wks
parietal decidua
lines that noninvolved areas of the rest of fetus
secretes progesterone and estrogen in first 3 to 4 months of pregnancy in low levels to inhibit menstruation until placenta takes over
corpus luteum
True labor
begins when contractions occurs in regular intervals
Stage of dilation
typically 6 to 12 hrs; time from onset to complete dialtion of 10cm; regular contractions;l usually rupturing of sac
Stage of Expultion
from the time of complete dilation to delivery of fetus; 10 mins to several hrs
Placental stage
time after deliver until placenta is expelled
Puerperium
6wks after delivery for maternal reproductive organs and physiology to return to prepregancy state
Organogensesis
all major organs develped between 4th thru 8 wks
Fetal Ultrasound
more accurate fetal age, confirm pregnancy, fetal position, indentifies mutliple pregnancies
Amniocentesis
perform 14 to 18wks; checks for genetic abnormalties
Chronic villi sampling
done to identify the same gentec defects as seen on amniocentesis; can be done at 8 wks and results in days
Maternal alpha fetoprotein (AFP)
blood from mother to detect high levels of AFP that indicates neural tube defects such as spina bifida or anencephaly