2nd & 3rd Tri Assessment Flashcards
What weeks are 2nd trimester? 3rd?
2nd: 13-26 wks
3rd: 27-40, can go to 42
What are the 3 germ layers from inner to outer?
endoderm, mesoderm, ectoderm
What does the endoderm become?
GI & respiratory systems
What does the mesoderm become?
MSK & circulatory systems
What does the ectoderm become?
brain, nervous system, skin
What are the two variants of vertex position?
anterior occiput: face toward mat spine
posterior occiput
What type of cephalic positioning is better for labor and delivery?
anterior occiput
What are the 3 types of breech positioning?
- complete: fetal bottom down, legs folded
- incomplete: bottom down, one leg bent & one straight up near ear
- frank: bottom down, legs straight up near ears
When are bony and soft tissue structures of the face seen?
bony: wk 12
soft tissue: wk 16
What facial structures do you see in a sagittal view?
frontal bone, nasal bone/nose, chin
What facial structures do you see in the coronal view?
- upper lip
- orbits/lens
- nostrils
- palate
What are two facial measurements?
OOD: outer to outer orbital diam
IOD: inner orbital diam
What structures are located within the thorax?
- lungs
- thymus
- diaphragm
- heart
- great vessels
How does the size of the thorax compare to the abdominal cavity?
thorax is slightly smaller
What 3 structures border the lungs medially, inferiorly, and laterally?
medial: heart
inferior: diaphragm
lateral: rib cage
What is the US appearance of fetal lungs?
solid, homogeneous, slightly more echogenic than liver
How much time does the fetus practice breathing?
1/3 of time
What are the two ways to record fetal respiration?
- watch diaphragm & ribs move
- CF on nostrils
How is the diaphragm best visualized? What does it look like?
- best vis. in sag, spine down
- thin, hypo line separating chest & abd cavities
What are fetal risk factors for fetal echo?
- IUGR
- IVF
- arrythmias
- abnormal amniocentesis w/ trisomy
- abnormal HR
- hydrops
What is fetal hydrops?
Fatal condition w/ abn accumulation of fluid in 2 or more compartments
What are maternal risk factors for fetal echo?
- family/personal hx of heart defect
- DM
- lupus
- substance abuse
- abnormal HR
What structures should be visualized in the 4 chamber heart?
- atria & ventricles
- valves
- intracardiac septae
- papillary muscles
- foramen ovale
- great vessels (ao, pulm art/vein, ivc/svc)
What is the RVOT?
pulmonary artery, leaves rt ventricle, PA has hockey stick appearance (ductal arch)
What is the LVOT?
aorta, leaves lt ventricle, ao has candy cane appearance
How is oxygenated blood supplied to the fetus?
brought to fetus by umbilical vein from placenta
Where does the umbilical cord enter the abdomen?
umbilicus
What happens to the blood as it reaches the liver via falciform ligament?
1/2 filters through the liver, 1/2 bypasses the liver via the ductus venosus
What hepatic vessel does the umbilical vein join?
left portal vein
Where does the IVC join the heart?
right atrium
How does the blood travel after entering the right atrium?
- portion travels to left atrium via foramen ovale
- rest travels from rt atrium to rt vent via tricuspid valve
- blood then leaves rt ventricle through pulm artery
How does blood travel from right to left atrium?
foramen ovale
How does blood travel from right atrium to right ventricle?
tricuspid valve
Where does blood travel after leaving the right ventricle through the rvot?
most enters ductus arteriosus & bypasses lungs, small amount travels to the lungs
What happens after the ductus arteriosus enters the descending aorta?
- desc ao enters umbilical arteries
- umbilical arteries within umbilical cord enter placenta
- bring blood from fetus back to placenta
What happens to the small amount of blood that travels to the lungs through the pulmonary artery?
- returns to lt atrium via pulmonary veins
- travels from lt atrium to lt ventricle via mitral valve
- travels from lt ventricle to asc. aorta via aortic valve
How does blood travel between the left atrium and left ventricle?
mitral valve
How does blood travel from the left ventricle to the ascending aorta?
aortic valve
What is the ratio of heart to thorax size?
1:3
How do the atria and ventricle size compare?
equal
How does the foramen ovale move?
it moves to the left with systole
What are the 3 embryologic components of the abdomen? What are they formed by?
foregut: cranial end fold
midgut: side folds
hindgut: caudal end fold
What does the foregut become?
- esophagus
- stomach
- duodenum
- liver
- biliary
- pancreas
- spleen
What does the midgut become?
- small intestines
- majority of colon
- cecum
- cloaca
What does the hindgut become?
- descending colon
- sigmoid colon
- bladder
- urethra
How does the growth of the midgut compare to the growth of the abdominal cavity?
midgut grows faster than abdominal cavity
What is the result of the liver and kidneys growing faster than the abdominal cavity?
results in herniation of the bowel which extends to the prox umbilical cord
When does fetal bowel herniation resolve?
week 11
When does the esophagus reach final length?
week 7
What divides the trachea and esophagus?
tracheoesophageal septum
When is the stomach visualized?
seen at 11 weeks due to swallowed amniotic fluid, must be seen after 16 weeks
What do the intestines appear like?
slightly hyperechoic to liver, appears mass-like
When are small and large intestines differentiated? When is peristalsis seen?
small and large differentiated at 20 weeks, peristalsis seen after 27 wks
What happens to the umbilical vein following birth?
forms ligamentum teres
How does fetal liver size compare to the body?
liver is 10% of fetal weight at 11 weeks and 5% at birth
What landmarks are included in AC measurement?
trv spine, fluid filled stomach, umbilical vein
What does the genitourinary system develop from?
intermediate mesoderm
What is the cloaca?
How feces & urine pass in embryos, at the end of the hindgut & divides into rectum, urinary tract & genitalia
What is the ureteral bud?
Forms from outpouching of wolffian duct, gives rise to ureter, renal sinus, collecting tubules
When does urine production begin?
week 16
What are the 3 sets of embryologic urinary excretory glands?
- pronephros: first set of kidneys, nonfunctioning
- mesonephros: 2nd set of kidneys, function for short period & degenerate
- metanephros: permanent kidneys, develop at wk 5 while mesonephros are acting
When do the kidneys rise in the abdomen and separate?
week 9
How does the appearance of the kidneys change from before 13 weeks to after 15 weeks?
before 13: hyperechoic
after 15: decreased echogenicity, still hyperechoic to surroudings
