3-3-16-Fetal And Neonatal Physiology (Lopez) Flashcards
Weeks 3-8 are described as the ___ period
Weeks 9-36 are described as the ___ period
Week 38 is considered ___ term
Embryonic
Fetal
Full
Major morphologic abnormalities can occur during weeks ___
Physiologic defects and minor morphologic abnormalities can occur during weeks ___
3-7
8-full term
list the 3 sequential phases of growth:
- Pure hyperplasia
- Hyperplasia and concomitant hypertrophy
- Hypertrophy alone
The time courses of the 3 phases of growth are organ specific–> placenta goes through all 3 phases of growth, but these phases are compressed b/c the placental life span is relatively short
___ is the primary form of placental growth
Growth of the fetus occurs almost entirely by ____
Hypertrophy
Hyperplasia
___ of the fetus increases almost in proportion to age
___ of the fetus increases almost in proportion to the cube of the age of the fetus
Length
Weight
List roles that the placenta plays in fetal growth and development:
- Transport and storage functions
- Synthesis of steroids (estrogen and progesterone) and protein hormones (hCG and hCS’s)
___ is an abnormality of fetal growth and development. The growth-restricted fetus is at substantial risk of morbidity and mortality and may occur as a result of decreased placental reserve caused by any insult
Intrauterine Growth Restriction (IGR)
Mothers who smoke during pregnancy tend to have small placentas and are at high risk of delivering a low birth weight baby
___ stimulate fetal growth
The fetus uses ___ as its major energy source
Glucocorticoids, insulin, GH, IGFs, and thyroid hormones
Glucose
___ promote the storage of glucose as glycogen in the fetal liver
___ contributes to the storage of glucose as glycogen, as well as to the uptake and utilization of AAs and lipogenesis
Glucocorticoids
Insulin
___ acts by binding to its receptors, primarily in the liver, and triggering the production of somatomedin or IGF-1
___ are mitogenic peptides that are extremely important for fetal growth
___ are obligatory for normal growth and development
GH (postnatally)= may only have a minimal effect on fetal growth, fetal liver has relatively few GH receptors
IGF-1/2=present in fetal circulation from end of 1st trimester, their levels increase thereafter in both mother and fetus
Thyroid hormones=hypothyroidism has adverse effects on fetal growth
The fetal heart begins beating during the __ week after fertilization, initially contracting at 65 bpm and rate increases steadily to ~140 bpm immediately before birth
4th
During the 3rd week of fetal development, nucleated RBCs are formed in the ___ of the placenta
Yolk sac and mesothelium
During the 4th-5th weeks of fetal development, non-nucleated RBCs form by __ cells of the fetal BV’s
Fetal mesenchymal and endothelial cells
At the 6th week of fetal development, the ___ now forms blood cells
Liver
At about the 12th week of fetal development, ___ tissues begin forming RBCs
The spleen and lymphoid
From the 3rd month on of fetal development, ___ becomes the principal sources of RBCs
Bone marrow–> also produces WBCs
___ begins to be formed in the 3rd week after fertilization, the content of which rises to ~15 g/dL by midgestation.
Hb–> [Hb] of fetal blood at term is higher than [Hb] of maternal blood, which may be only 12 mg/dL
Fetal Hb has higher affinity for O2: can carry 20-30% more O2 than maternal Hb
Most of the reflexes of the fetus involving the spinal cord and brain stem are present by __ months after pregnancy
3rd-4th
Cerebral cortex development continues after birth
___ is composed of swallowed amniotic fluid and partly of mucus, epithelial cells, and other residues of excretory products from the GI tract and glands
Meconium
Regarding fetal metabolism, ___ accumulates rapidly starting at 12 weeks gestation. About 1/3 of this compound in a fully developed fetus is stored in the liver and can be used for formation of additional Hb
Iron
