Maternal Newborn 3 Flashcards
Implantation of the blastocyst:
The embedding of the blastocyst( composed of an inner cell mass known as the embryoblast, which will develop into the embryo) into the endometrium of the uterus, begins around day 5 or 5.
Where does implantation begin?
Implantation normally occurs in the upper part of the posterior wall of the uterus.
Embryo:
The developing human is referred to as an embryo from the time of implantation through 8 weeks of gestation.
What is Organogenesis:
The formation and development of body organs, which occurs during the first 8 weeks of gestation.
When do the primary germ layers develop?
Around day 14
Ectoderm:
This is the outer germ layer and the primary structures developed are the epidermis(hair, skin, nail, sweat glands), Nervous system, pituitary gland, adrenal medulla, lens and cornea, internal ear, mucosa of oral and nasal cavities, and salivary glands.
Mesoderm:
The middle germ layer and the primary structured developed are the Dermis, bone and cartilage; skeletal muscles; cardiac muscle, most smooth muscles, kidney; adrenal cortex, bone marrow, and blood; lymphatic tissue; and the lining of blood vessels.
Endoderm:
The inner germ layer and the primary structures developed are the Mucosa of esophagus, stomach and intestines; epithelium of respiratory tract, including lungs; and liver and mucosa of gallbladder; and thyroid gland, and pancreas.
When does the heart form:
During the 3rd gestational week and begins to beat and circulate blood during the 4th.
What gestational week does the human transform from primary germ layer to a clearly defined human that is 3 cm in length with all organ systems formed?
By the end of the 8th gestational week.
When is the developing human referred to as a fetus:
From week 9 to birth. During this stage of development, organ systems are growing and maturing.
How does oxygenated blood enter the fetal circulatory system?
High levels of oxygenated blood enter the fetal circulatory system from the placenta via the umbilical vein.
How does the majority of the high oxygenated blood enter the right atrium?
By way of the ductus venous, which connects the umbilical vein to the inferior vena cava.
What is the opening in the heart between the right and left atria:
The foramen ovale; Oxygenated blood is shunted to the left atrium via the foramen ovale. After birth it closes in response to increased blood returning to the left atrium. This can take up to 3 months to fully close.
Ductus Arteriosus:
Connect the pulmonary artery with the descending aorta. The majority of the oxygenated blood is shunted to the aorta via the ductus arteriosus with smaller amounts going to the lungs. After delivery, the ductus arteriosus constricts in response to the higher blood oxygen levels and prostaglandins.
Metabolic and gas exchange:
In the placenta, fetal waste products and CO2 are transferred from the fetal blood into the maternal blood sinuses by diffusion. Nutrients, such as glucose and amino acids, and O2 are transferred from the maternal blood sinuses to the fetal blood through the mechanisms of diffuse and active transport.
Hormone Production of the placenta:
The major hormones the placenta produces are progesterone, estrogen, human chorionic gonadotropin(hCG), and human placental lactogen(hPL), also known as chorionic somatonmammotropin.
What does progesterone do?
Progesterone facilitates implantation and decreases uterine contractility.
What does estrogen do ?
Estrogen stimulates the enlargement of the breasts and uterus.
What does hCG do:
hCG stimulates the corpus luteum so that it will continue to secrete estrogen and progesterone until the placenta is mature enough to secrete these hormones. This is the hormone assessed in pregnancy tests. hCG rises rapidly during the first trimester and then has a rapid decline.
hPL:
Promotes fetal growth by regulating glucose available to the developing human. It also stimulates breast development in preparation for lactation.
Week 12 Gestation:
8cm & 45 grams/ RBC produced in liver; fusion of palate complete; external genitalia developed to the point that sex of fetus can be noted with u/s; eyelids closed; fetal heart tone can be heard by Doppler.
Week 16 Gestation:
14cm & 200 grams/ Lanugo is present on head; Meconium is formed in the intestines; teeth begin to form; sucking motions are made with mouth; skin is transparent.
Week 20 Gestation:
19cm & 450 grams / Lanugo convers the entire body; vernix caseosa covers body; nails are formed; brown fat begins to develop.