Fetal Growth and Development Flashcards
Menstrual age is usually __ weeks before ovulation and fertilization
2 weeks
This is the elapsed time since the first day of the LMP
Menstrual age or Gestational age
Menstrual age is nearly __ weeks before implantation of the blastocyst
3 weeks
The number of days and calendar month duration of mestrual age
280 days
9 1/2 months
This starts 3 weeks after ovulation
Embryonic period
Positive pregnancy test
3 weeks after ovulation
Embryonic disc is well defined, the body stalk is differentiated
3 weeks after ovulation
Chorionic sac is approximately 1 cm
3 weeks after ovulation
There is a true intervillous space that contains maternal blood
3 weeks after ovulation
Villous core in which angioplasties chorionic mesoderm can be distinguished
3rd week after ovulation
Chorionic sac is 2 to 3 cm in diameter
4th week after ovulation
Embryo is about 4 to 5 mm in length
4th week after ovulation
Partitioning of the primitive heart begins
4th week after ovulation
Arm and leg buds are present
4th week after ovulation
Amnion begins to unsheathe the body stalk which becomes the umbilical cord
4th week after ovulation
The embryo is 22 to 24 mm in length
6th week after fertilization
Head is quite large compared to the trunk
6th week after fertilization
Heart is completely formed
6th week after fertilization
Fingers and toes are present
6th week after fertilization
Arms bend at the elbow
6th week after fertilization
Upper lips is complete
6th week after ovulation
External ears from definitive elevations on either side of the head
6th week after fertilization
This occurs 8 weeks after fertilization or 10 weeks after the onset of the last menstrual period
Fetal period
The embryo fetus is nearly 4cm long
Fetal period
The major portion of lung development is yet to occur
Fetal period
The crown rump length of the fetus is 6 to 7 cm
12 gestational weeks
Centers of ossification have appeared in most of the fetal bones, and the fingers and toes are differentiated
12 gestational weeks
Skin and nails have developed and scattered rudiments of hair appear
12 gestational weeks
The external genitalia are beginning to show definitive signs of male or female gender
12 gestational weeks
The fetus begins to make spontaneous movements
12 gestational weeks
The crown rump length of the fetus is 12 cm
16 gestational weeks
What is the weight of the fetus in a 16 gestational week
110 grams
The gender can be correctly determined by experienced observer by inspection of the external genitalia by ___
14 weeks
The fetus now weights somewhat more than 300 grams
20 gestational weeks
Weight begins to increase in a linear manner
20 gestational weeks
The fetal skin has become less transparent, a downy lanugo covers the entire body, and some scalp hair has developed
20 gestational weeks
The fetus weighs around 630 grams
24 gestational weeks
The skin is characteristically wrinkled and fat deposition begins
24 gestational weeks
The head is STILL comparatively large and eyebrow and eyelashes are usually recognizable
24 gestational weeks
The canalicular period of lung development occurs during which bronchi and bronchioles, enlarge and alveolar ducts develops
24 gestational weeks
Canalicular period is nearly completed by the ___
28 gestational weeks
Crown rump length of about 25 cm
28 gestational weeks
The fetus weighs around 1100 grams
28 gestational weeks
And infant born at this time moves limbs energetically
28 gestational weeks
Cries weakly
28 gestational weeks
The otherwise normal infant of the age has a 90% chance of survival without physical or neurological impairment
28 gestational weeks
Crown rump length of about 28 cm
32 gestational weeks
The weight of the fetus is about 1800 grams
32 gestational weeks
The skin surface is still red and wrinkled
32 gestational weeks
Infants born at this period also usually survive intact
32 gestational weeks
The crown rump length of the fetus is about 32 cm
36 gestational weeks
The weight of the fetus is about 2500 grams
36 gestational weeks
Deposition of subcutaneous fat, the body has become more rotund
36 gestational weeks
Infants born at this time have an excellent chance of survival with proper care
36 gestational weeks
Fetus is fully developed
40 gestational weeks
Crown rump length of the fetus at term is about 36 cm
40 gestational weeks
The fetus weight is approximately 3400 gram
40 gestational weeks
Sutures between two frontal bones
Frontal
Suture between two parietal bones
Sagittarius
Between frontal and parietal bones
Coronal sutures
Between posterior margins of the parietal bones and upper margin of the occipital bone
Lambdoid suture
Where several sutures meet, an irregular space forms which is enclosed by a membrane
Fontanels
Is a lozenge-shaped space situated at the junction of the Sagittarius and the coronal sutures
Greater or Anterior fontanel
Small triangular area at the intersection of the sagittal and lambdoid sutures
Lesser or posterior fontanel
Give the measurement of the following: Biparietal: Bitemporal: Occipitomental: Suboccipitobregmatic: Occipitofrontal:
- 5 cm
- 0 cm
- 5 cm
- 5 cm
- 5 cm
The greatest circumference of the head corresponds to the plane of the ____ diameter that averages ___ cm
Occipitalfrontal diameter
34.5 cm
The smallest circumference corresponds to the plane of the ____ diameter which is ___ cm
Suboccipitobregmatic diameter
32 cm
Myelination of the ventral root of the cerebrospinal nerves and brainstem begins at approximately:
6 months
This is the organ of transfer between mother and fetus
Placenta
Occasional development of breaks in the chorionic villi is seen in:
Sensitization of erythrocytes of their D-positive fetus
The ____ and _____ together function for the fetal as lung, GI and kidney
Chorionic villus
Intervillous space
Residual volume of the intervillous space of the term placenta measure ___ ml
140 ml
Uteroplacental blood flow NEAR TERM has been estimated to be ___ with most blood apparently going to the intervillous space
700-900ml/min
Blood pressure in the intervillous space is significantly ___ the uterine arterial pressure but somewhat __ the uterine venous pressure
Less than
Greater than
Uterine venous pressure varies depending on several factors such as the ___
Maternal position
Substances that pass from the maternal blood to the fetal blood must traverse this:
Syncytiotrophoblast
Storma of the intravillous space
Fetal capillary wall
This actively or passively permits, facilitates, and adjust the amount and rate of transfer if a wide range of substances if the fetus
Syncytiotrophoblast
The total surface area of capillaries? at term has been estimated to be approximately
10 m2
In the regulation of placental transfer what is the fetal tissue interface
Syncytiotrophoblast
The maternal facing surface of the placental transfer is characterized by _____
Complex microvillous structure
This is the site of transfer to the intravillous space through which the fetal capillaries traverse
Fetal facing basal cell membrane
Determining of the effectiveness of the human placenta as organ transfer, at least 10 variables are important:
- concentration of the substance in the maternal plasma bound to carrier protein
- rate of maternal blood flow in the intervillous space
- area available for exchange across the villous trophoblast epithelium
- substance transferred by diffusion the physical properties of the tissue barriers
- receptors for active transport
- amount metabolized by the placenta
- area for exchange across fetal capillaries in the placenta
- bound substance in the fetal blood
- specific carrier protein in the fetal circulation
- rate of blood flow through the villous capillaries