What milestones happen at 4 weeks?
Heart develops, double chambers visible, begins to beat; aortic arch and major veins completed
What milestones happen at 8 weeks?
Eyes, ear, nose and mouth are recognizable.
First indication of ossification.
Definitive trunk, limbs, and head.
Testes and ovaries distinguishable; external genitalia is sexless but begins to differentiate
What milestones occur at 12 weeks?
Nails begin to appear; resembles a human.
Bile is secreted.
Smooth muscle layers indicated in hollow viscera.
Blood forms in marrow.
Lungs acquire definite shape and vocal cords appear.
Kidney able to secrete urine; bladder expands as a sac.
Sucking is pr
What milestones are reached at 16 weeks?
Arm/leg ratio proportionate; scalp hair appears.
Meconium in bowel; some enzyme secretion and anus open.
Joint cavities appear; muscular movements can be detected.
Heart muscle well developed; blood formation in the spleen.
Bronchioles appear.
Kidneys ful
What milestones occur at 20 weeks?
Vernix, lanugo and sebaceous glands appear.
Enamel and dentine deposition.
Sternum ossifies; mother can feel movements.
Respiratory-like movements begin.
Nose and ears ossify.
What milestones occur at 24 weeks?
Skin is red and wrinkled and sweat glands form.
Blood formation increases in bone marrow and decreases in liver.
Alevolar ducts and sacs present, lecithin begins to appear (week 26-27).
Can hear.
What milestones occur at 28 weeks?
Pupils capable of reacting to light.
Indefinite sleep-wake cycle.
What milestones occur at 30-31 weeks?
Subcutaneous fat beginning to collect; skin is smooth and assumes birthing position.
Can turn head side to side.
Sense of taste and hears sounds.
What milestones occur at 36 weeks?
Sustained, definite movements; can turn and elevate head.
L/S ratio: >2:1.
What milestones occur at 40 weeks?
Active, sustained movement; good tone.
Pulmonary branching only 2/3rds complete.
Myelination of brain begins; patterned sleep-wake cycle with alert periods; strong suck reflex.
Testes in scrotum.
When does the heart develop into four chambers?
Between 4th and 5th week.
What three special characteristics enable the fetus to obtain sufficient oxygen from the maternal blood?
1)Fetal hemoglobin has a high affinity for oxygen and carries 20%-30% more oxygen than maternal hemoglobin
2)The hemoglobin concentration of the fetus is about 50% greater than that of the mother
3) The fetal heart rate is 110-160 beats/minute, making the
When does hematopoiesis begin in the liver?
6th week
When are the antigenic factors that determine blood type present in RBCs?
6th week
When does the fetus begin swallowing amniotic fluid?
5th week
When is glycogen synthesized in the liver?
9th or 10th week
Between what weeks does stores of brown fat deposit under the dermis?
26-30 weeks
When does bile, a constituent of meconium, begin to form?
12th week
When are the kidneys fully developed?
9 weeks
When are brain waves first recorded?
by week 8
When can a fetus respond to sound?
week 24
When does thyroid gland develop? When does thyroxine get secreted?
3rd-4th week; 8th week
When does the adrenal cortex form? When does it start secreting hormones?
6th week; 8th or 9th week