Ch 12 Conception And Fetal Development Flashcards
Implantation
Occurs between 6-10 days after fertilization
Bleeding or spotting may occur
Fetal membranes
Chorion
Amnion
Chromosomes
XX female XY male
Amniotic fluid purpose
Space for movement and protection Thermo regulation Supplies fetus with nutrients and fluid Can be tested for genetic disorders Prevents amnion (layer of the amniotic sac) from sticking to fetus Prevents umbilical cord compression
Amniotic fluid amount
800 to 1200 ml present at birth
Polyhydramnios
Too much amniotic fluid, more that 2000 ml
Could indicate GI malformation of the fetus
Oligohydramnios
Not enough amniotic fluid
Less than 300 ml
Associated with renal malformations
Umbilical cord is protected by
Wharton’s jelly
Vessels in umbilical cord
2 arteries 1 vein
Arteries away from fetus
Vein carries oxygen rich blood to fetus
Organs in the fetus originally develop where?
In the umbilical cord because the abdomen is so small in the beginning
Placenta
Considered an endocrine gland
Secretes hcg, hpl, estrogen, progesterone
Hcg detected how long after conception
10 days (in maternal serum)
Hpl
Human placental lactogen, also known as chorionic somatotropin
Similar to human growth hormone, needed for fetal development
Stimulates maternal metabolism to supply nutrients needed for fetal growth
Placental development
Develops during week three and is fully functional by week 12
Other placenta jobs
Regulates transport of gases, nutrients, and waste
Dirty Duncan
Maternal side
Shiny Schultz
Fetal side
Pre-embryonic stage
Conception to day 14
Rapid cell division
Primary germ layers and the embryonic membranes form
The primary germ layers are the basis for all tissues and all organs to grow from
Embryonic stage
Day 15 to week eight
Structures of major organs are complete and organ systems are functioning
Big risk for teratogens
Most deformities will occur between weeks three and week eight
Examples of teratogens
Radiation, lead, chemotherapy agents, cmv (a virus), MMR vaccine (avoid pregnancy 28 days after vaccine), rubella
Month one
Hematopoiesis (formation of blood cells)week three
Day 25 the heart is beating
Fourth week the GI system is functioning
In the first month the liver, thyroid, bones, muscles and epidermis are forming
Neural tube (start of central nervous system)
At the end of this month the fetus is half an inch long and less than 1 oz
First functioning organ system
Cardiac system
Month two
Ears, ankles, wrists are developed The eyelids are still shut Hematopoesis continues By the fifth week is swallowing and voiding The brain has five lobes Pancreas and nerve fibers are developing At the end of month two fetus is 1 in long and less than 1 oz Rh factor is developed by about 6 weeks
Month three
Baby has fingers and toes, soft nails, baby teeth
Can hear fetal heart rate with Doppler
Renal function
Baby starting to move
Adrenal cortex is producing hormones
Reproductive parts begin to develop and sex characteristics begin to develop (may not be visualized)
Lanugo and vernix
By the end of month three baby is 2 1/2 in long and greater than 1 oz
