Fetal Growth And Devlelopment Flashcards
How does weight gain of the fetus change throughout pregancy?
Is slow at first, but becomes increasinhly rapid in the mid and late fetal periods
What are the main features of emboryonic growth?
Intense morphogenesis and differenation, with little weight gain and the placental growth is most significant
What are the features of growth in the early fetus?
Protein deposition
What are the features of growth in the late fetus?
Adipose depsostion
How do the body proportions of the fetus change?
At 9 weeks the head is about ahlf the crown rump lenth, and thereafter the body length and the lower limb growth accelarates
How can ultrasound scans be used in pregancy?
Can be used early in pregnancy to calculate age, and also rule out ectopic pregnancies and the number of foetuses, and is routinely carried out at about 20 weeks to assess fetal growht and fetal anaomlies
When would you measure the crown rump length?
Between 7-13 weeks to date the pregancy and estimate the date of devlivery
What is the parietal daimaete wand when would you use it?
Teh distance between the parietal bones of the fetal skull, and is used in combination with other measurments to date pregancies in T2 and T3
When would you use the abdominal circumfrance and femur length?
Used in combination wiht BPD to dating and growht montiting, and is also useufl for anaomly detection
What parts of the lung develop within the emboryonic period?
The borchopulmonary tree
What is the membrane that seperates the devlopng respiratory and Gi tracts?
The tracheooesphageal speutm
When is the pseduglandular stage of lung development?
Duct system beings to form within the brochopulmonary segments created during the emboroynic period, and is forming the brochioles between weeks 8-16
What is the canialicular stage?
The formation of the respiratory brochioles, budding from brochioles formed during the pseduoglandular stage, and occurs beween weeks 16 and 26
What is the terminal sac stage?
From weeks 26 onwards, terminal sacs begin to bud from the respiratory bronchioles, causing the differenitation of the type I and type II pneumocytes and therefore the production of surfactant
What is the role of the lungs between T2 and T3?
Gas echange conducted at the placental, but lungs must be prepared to assume the burder, and the breathing movements are used to condition the respiraotory muscles, and are fluid filled whihc are crcuicla fro normal lung deelopment
What is the threshold of viability?
Vibaility is only a possibilty once the lungs have entered the terminal sac stage of devleopment, therefore >24 weeks
What is respiratory distress syndrome of the neonate?
Often occurs in infants born prematruely, there is insufficent surfactatn production, as you do not have adquate numbers of type two pneumocytes,.
How can you try and prevent respiratory distress sydndrome of the infant?
If pre term delivery is inevitable or unavoidable, give the mother gluocortocid treatment which drives the increased production of surfactant
What is the role of the urianry system in the fetus?
The fetal kidney fucntion beings in week ten, and fetal urine is a major contributor to the aminotic fluid volume, and fetal kidney function is not neccessary for survial in utero but without it there is olgiohyrdominoas
What is olgiohydromaonias?
To little aminotic fluid, caused by placentla insufficeny, or fetal reanl impairment
What is polyhrdomonais?
Too much amniotic fluid, cna be idipathic and causes fetal abnormalities such as inability to swallow
When do the cortciospinal tracts begin to ofomr?
These are required for volunatry movement and begin to form in the 4th month
When does the myelination of the brain beigin?
In the 9th mont
Hwo does the nervous sytem develop after briht?
Cortciospinal trac myelination incomplete at birht, and is evidecnet by the increasing infant mobility in the 1st year
What are some of the features of devleopment of the sensory and moto systems?
There is no movemetn until the 8th weeks, thereafter a large respotire of movements develop that are practsiing for post natatl life such as sucking and breathing
