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At what stage of embryologic development does the ovum enter the uterus?
The respiratory system arises from which of the following germ layers?
- Reference page 7.
The earliest development of the lung begins at:
b. 24 days
c. 36 days
d. 8 weeks
Dichotomy of the airways occurs during which phase of lung development?
- Reference page 9
Which of the following statements best describes surface tension?
a. diffusion of similar molecules following concentration gradients
b. the inward movement of surface molecules due to kinetic energy
c. the tendency of a liquid surface to contract.
d. the attraction of surface water molecules to gas molecules.
- The tendency of a liquid surface to contract.
- Reference page 10.
Which of the following, when found in amniotic fluid, is the best indicator of fetal lung maturity?
Which of the following does not appear to accelerate fetal lung maturation?
C. Maternal preeclampsia
- Maternal preeclampsia
- Reference page 14
Which of the following are true concerning lung fluid?
I. There is approximately 20 to 30 ml/kg present at birth.
II. At term, it is produced at a rate of 2 to 4 ml/kg/hr.
III. It has lower pH, protein, and bicarbonate levels than amniotic fluid.
IV. It has lower sodium and chloride concentrations than amniotic fluid.
V. It maintains the patency of the developing airways.
a. I, III, V
b. II, IV, V
c. I, II, III, V
d. I, II, III, IV
- I. There is approximately 20 to 30 ml/kg present at birth.
- II. At term, it is produced at a rate of 2 to 4 ml/kg/hr.
- III. It has lower pH, protein, and bicarbonate levels than amniotic fluid.
- V. It maintains the patency of the developing airways.
- Reference page 15
Which of the following may occur following Cesarean section?
c. Diaphragmatic hernia
d. Aspiration pneumonia
The heart develops form which germ layer(s)?
The embryologic truncus arteriosus develops into:
I. The vena cava
II. the pulmonary artery
III. the atria
IV. the aorta
V. the right and left ventricles
a. IV, V
b. I, III
c. I, II, III
d . II, IV
- II. the pulmonary artery
- IV. the aorta
- Reference page 18
Which of the following describes the path of blood that is shunted through the foramen ovale?
a. from the umbilical vein to the inferior vena cava
b. from the right to left atrium
c. from the right to left ventricle
d. from the iliac artery to the umbilical artery.
- From the right to left atrium
- Reference page 20
The ductus arteriosus shunts blood from:
a. the pulmonary artery to the aorta
b. the right to left atrium
c. the umbilical vein to the inferior vena cava.
d. the right to left ventricle
- The pulmonary artery to the aorta
- Reference page 20
Which of the following statements is correct?
a. Baroreceptors are not active during fetal life.
b. Baroreceptors sense changes in Pa02, pH, and PaCO2
c. Baroreceptors are actually stretch receptors
d. Baroreceptors are instrumental in the initiation of the first breath.
Baroreceptors are actually stretch receptors.Reference page 21
Stimulation of baroreceptors causes what?
Bradycardia and hypotension
In the placenta, the fetal vessels are contained in the:
a. intervillous space
c. spiral arteries
d. chorionic villi
- Chorionic villi
- Reference page 22
What are chemoreceptors sensitive to?
Pa02, PaC02, and pH
Where are chemoreceptors located?
- On the carotid arteries and aorta or the carotid and aortic bodies.
- (Function in the initiation of the first breath.)
What is the wharton's jelly? How many umbilical veins and arteries?
Wharton jelly prevents from occluding of the umbilical cord. There are two umbilical arteries and one umbilical vein.
Polyhydramnios is defined as:
a. an absence of amniotic fluid
b. a decreased amount of amniotic fluid
c. infection of the amniotic fluid
d. an excessive amount of amniotic fluid
- An excessive amount of amniotic fluid.
- Reference page 24
Which of the following are possible causes of polyhydramnios?
II. esophageal atresia
III. choanal atresia
IV. Down syndrome
V. cleft palate
a. II, III, IV, V
b. I, II, IV
c. I, II, IV, V
d. I, II, III, IV, V
- I. hydrocephalus
- II. esophageal atresia
- IV. Down syndrome
- V. cleft palate
When the endometrium begins eroding, creating pockets around the villi that will contain the maternal blood. What are these spaces called?
The maternal surface contains 15 to 28 segments. What is this called?
What do each cotyledon possess?
A chorionic villus and an intervillous space.
True or false: The fetal blood has high levels of C02 and waste materials but is low in oxygen and nutrients. In contrast, the maternal blood has high levels of oxygen and nutrietns but is low in CO2 and waste materials.
True or False: The normal placenta is round, occupies about one third of the uterine surface, and weighs around 1 pound, or 15 to 20% of the fetal weight at term.
What is the amnion?
The sac that surrounds the growing fetus and contains the amniotic fluid.
What are functions of the amniotic fluid?
- Protection from traumatic injury
- Facilitation of fetal movement
What is oligohydramnios?
Scant or decreased amount of amniotic fluid.
What causes oligohydramnios?
- Usually associated with a defect in the urinary system.
- Renal dysplasia or agenesis as well as urethral stenosis are involved.
During what period is pulmonary surfactant produced in increasing amounts by the Type II alveolar cells?
What is Laplace's Law?
As the radius of the alveoli decreases, surface tension increases.
At what gestational week is mature surfactant present?
The first surfactant produced lacks PG and is termed what?
What is the lecithin (PC) to sphingomyelin ratio when fetal lungs are beginning to mature?
The combination of the L/S ratio and testing for PG is called what?
What is the foam test?
- When amniotic fluid is mixed with ethanol. The mixture is shaken for 15 seconds and read 15 minutes later.
- If there is a ring of bubbles, there is enough lecithin present.
Describe fetal circulation. BE IN GREAT DETAIL.
The pressure found inside the fetal vasculature are the reverse of those found in teh adult. Pressures int he venous system are higher than those in the arterial system. There are two reasons for this.
- 1) During the development of the fetus, the growing lungs provide a very high resistance to blood flow. This high resistance is secondary to pulmonary vasculature constriction caused byt he low Pa02 in the fetal blood and also by teh fact that the lungs are for the most part collapsed.
- (In short low Pa02, lungs collapsed, pulmonary artery constriction.)
- Thus this increases the prsesures in teh right ventricle, right atrium, and vena cava.
2) Placenta offers very little resistance to blood flow. Low resistance causes low pressures in the aorta, left ventricle, left atrium, and the entire arterial system.
- Now onto the actual circulation...
- 1) Umbilical vein carries into first shunt, the ductus venosus. 50% is in the liver, the rest goes through the ductus venosus towards the inferior vena cava.
2)After arriving at the right atrium from the inferior vena cava, most of the blood shunts through the foramen ovale to the left atrium. There is a flap that acts as a one way valve for the foramen ovale that closes shut when the pressures int he left atrium are greater than right. This allows no shunted blood to move backwards. The rest of the blood moves on towards the right ventricle.
3)Upon the right ventricle meeting the pulmonary artery, there is another shunt, the ductus arteriosus. It joins the pulmonary artery to the aorta. Most of the blood enters the shunt, leaving only 10% to perfuse the lungs.
4) After the blood reaches the aorta, blood perfuses the mothers extremeities while 60% goes through the umbilical arteries where the cycle starts again.
Assessment of the fetus in the first trimester is facilitated by which technique?
a. high-resolution ultrasound
b. Doppler velocimetry
c. real-time displays
d. transvaginal ultrasound
What is amniocentesis?
Obtaining a sample of amniotic fluid by inserting a 3.5 to 4 inch 20 to 22 gauge needle ttached to a syringe into a pocket of amniotic fluid. The position for insertion of the needle is guided by ultrasound. Once the needle is inserted, 20 to 30 ml of amniotic fluid are aspirated and placed into sterile tubes.
What are complications of amniocentesis?
Trauma, infection, and hemorrhage.
Which of the following can be performed when an amniotic sample is obtained?
I. L/S ratio
III. Bilirubin level
IV. creatinine levels
V. Identification of meconium staining
VI. cytologic examination of cells
All of the above
A high level of AFP is good in determining what?What about low?
1) Neural tube defects such as anencephaly or meningomyelocele (spina bifida)
2) Down syndrome
Increasing amount of bilirubin in amniotic fluid is a sign of what?
Creatinine in amniotic fluid is used to determine what?
Fetal kidney maturaity
What is the average heart rate in early gestation?
What are the three ways to monitor fetal heart rate?
1)Abdominal transducer - senses the movement of the fetal heart and its valves and can determine heart rate.
2) Placing electrodes on abdomen
3) Placement of a small spiral electrode into the fetal scalp (most accurate)
Fetal heart monitor is excellent in monitoring what in utero?
It is excellent in identifying infants who asphyxiated in utero
There are two methods in measuring uterine contractions. What are they?
- 1) tocodynamoeter (most commonly used)
- 2)intrauterine pressure catheter (only used for difficult prolonged labors)
Why must the fetal heart rate be assessed so crucially?
Even within normal limits, a decrease or increase in baseline heart rate of 20 to 30 bpm may be abnormal even though still within normal limits.
What is fetal bradycardia?
A baseline heart rate of less than 100 bpm or a maintained drop of 20 bpm from the previous baseline.
What is the most dangerous cause of fetal bradycardia?
What is fetal tachycardia?
When baseline is consistently above 180 bpm.
What is the most common cause of fetal tachycardia?
If FHR exceeds 160 bpm for less than 2 minutes, it is called what? Is it good or bad?
- It is good because the fetus is reacting ot the contraction in a positive way.
What is it called when the fetal heart rate drops below 120 bpm for less than 2 minutes.
Decelerations. May be threatening or harmless.
What is Type I deceleration?
May drop to 60-80 bpm during contraction rapidly returning to baseline following contraction.
- Caused by compression of the fetal head against the cervix and are benign.
- Bradycardia is due to a parasympathetic response and is not indicative of hypoxia
What is Type II decelerations?
Do not follow uterine contractions. Occur 10 to 30 seconds following the onset of a contraction. Heart rate does not return to baseline until after contraction is over. Even a small decrease of 10 to 20 bpm from baseline is suggestive of problems.
Secondary to uteroplacental insufficiency during contractions, leading to fetal asphyxia.
What are type III decelerations?
- Are independent of uterine contractions.
- Secondary to compression of the umbilical cord, leading to hypoxia. May be wrapped around neonate's neck.
When is fetal scalp pH assessment indicated?
- 1) absence of baseline variability
- 2) late decelerations with decreasing variability
- 3) abnormal tracings
Tell me about fetal blood pH.
- Normal fetal pH is considered to be above 7.25.
- A pH of 7.2 to 7.24 shows slight asphyxia
- A pH of less than 7.2 signifies severe asyphyxia.
Which of the following cannot be detected by ultrasound?
a. Presence of infection
b. position of the fetus
c. position of the placenta
d. volume of amniotic fluid
Presence of infection
A high level of alpha-fetoprotein found during amniocentesis indicates which of the following?
a. neural tube defect
b. heart anomaly
c. fetal infection
d. Down syndrome
- Neural tube defect
- Reference page 34
Which of the following tests done on amniotic fluid is used to help determine fetal kidney maturity?
a. bilirubin level
b. L/S ratio
c. creatinine level
d. cytologic cell examination
- Creatinine level
- Reference page 34
Monitoring of the fetal heart rate during labor and delivery is used to detect:
I. uterine contractions
II. placental insufficiency
III. rupture of the amniotic sac
IV. compression of the umbilical cord
V. bradycardia secondary to a vagal stimulus
- II. placental insufficiency
- IV. compression of the umbilical cord
- V. bradycardia secondary to a vagal stimulus\
- Reference page 37
The most accurate method of measuring fetal heart rate is:
a. Doppler sensors
d. fetal scalp electrode
- Fetal scalp electrode
- Reference page 36
A common cause of fetal bradycardia is:
b. congential anomaly
c. heart defect
d. tocolytic drugs
- Reference page 37
Type III decelerations are caused by which of the following?
a. uterine contractions
b. placental insufficiency
c. rupture of the amniotic sac.
d. compression of the umbilical cord
- Compression of the umbilical cord
- Reference page 39
Which fetal scalp pH is the lower limit of normal?
What is Nagele's rule? Explain.
- Most common method of determining EDC.
- To determine EDC, 3 months are subtracted from the first day of the last menstrual period. Seven days are then added to the result to determine the EDC.
What is fundal height? Explain.
Another method of determining EDC. By measuring the distance from the symphysis pubis to the top of the fundus. During the first 2 trimesters it is fairly accurate. 20th week gestation = 20 cms.
What is quickening? Explain
First sensation of fetal movement experienced by the mother. Occurs between 16-22 but on average 20th week gestation.
Fetal heartbeat determining EDC. Explain.
Fetal heart beat can be heard as early as 16 weeks, but no later than 20. Can be heard on 8th week with the use of Doppler.
What is the contraction stress test?
Determine uteroplacental insufficiency
A positive CST is defined as more than 50% of contractions having late FHR decelerations.
A negative CST, no decelerations are seen after are seen after any contractions.
Contraindications to CST?
placenta previa, previous vertical cesarean section, previous uterine rupture, premature labor, premature rupture of the membranes, and incompetent cervix