FETAL DEVELOPMENT

Question 1

FIRST 14 DAYS AFTER FERTILIZATION

Answer 1

preembryonic or germinal stage

Question 2

week 3 - primitive nervous system, eyes, ears, RBC present, heart begins to beat day 21

Answer 2

embryonic stage

Question 3

FROM WEEK 9 UNTIL 38 TO 40 WEEK / FULLTERM

Answer 3

FETAL STAGE

Question 4

• Central nervous system (brain and spinal cord)
• Peripheral nervous system
• Skin, hair, and nails
• Sebaceous glands
• Sense organs
• Mucous membranes of the anus, mouth, and nose
• Tooth enamel
• Mammary glands

Answer 4

Ectoderm

Question 5

• Supporting structures of the body
  (connective tissue, bones,cartilage, muscle, ligaments,and tendons)
• Dentin of teeth
• Upper portion of the urinary system
  (kidneys and ureters)
• Reproductive system
• Heart
• Circulatory system
• Blood cells
• Lymph vessels
• Entoderm Lining of pericardial, pleura, and peritoneal cavities
• Lining of the gastrointestinal tract, respiratory tract, tonsils, parathyroid, thyroid, thymus glands
• Lower urinary system (bladder and urethra)

Answer 5

Mesoderm

Question 6

Lining of pericardial, pleura, and peritoneal cavities
- Lining of the gastrointestinal tract, respiratory tract, tonsils, parathyroid, thyroid, thymus glands
- Lower urinary system (bladder and urethra)

Answer 6

Endoderm

Question 7

• Arms and legs are budlike structures.
• Rudimentary eyes, ears, and nose are discernible.

Answer 7

End of 4th Gestational Week

Question 8

• Organogenesis is complete.
• External genitalia are forming, but sex is not yet distinguishable by simple observation.

Answer 8

End of 8th Gestational Week

Question 9

• Spontaneous movements are possible, although they are usually too faint to be felt by the mother.
• Some reflexes, such as the Babinski reflex, are present.
• The heartbeat is audible through Doppler technology.

Answer 9

End of 12th Gestational Week (First Trimester)

Question 10

• Fetal heart sounds are audible by an ordinary stethoscope.
• Sex can be determined by ultrasound.

Answer 10

End of 16th Gestational Week

Question 11

• Spontaneous fetal movements can be sensed by the mother.
• Antibody production is possible.
• The hair forms on the head, extending to include eyebrows.
• Passive antibody transfer from mother to fetus begins.
• Definite sleeping and activity patterns are distinguishable (the fetus has developed biorhythms
that will guide sleep/wake patterns throughout life).

Answer 11

End of 20th Gestational Week

Question 12

• Meconium is present as far as the rectum.
• When fetuses reach 24 weeks, or 601 g, they have achieved a practical low-end age of viability (earliest age at which fetuses could survive if born at that time), if they are cared for after birth in a modern intensive care facility.
• Hearing can be demonstrated by response to sudden sound.

Answer 12

End of 24th Gestational Week (Second Trimester)

Question 13

Testes begin to descend into the scrotal sac from the lower abdominal cavity

Answer 13

End of 28th Gestational Week

Question 14

• Fetus responds by movement to sounds outside the mother’s body.
• Active Moro reflex is present.

Answer 14

End of 32nd Gestational Week

Question 15

• Most babies turn into a vertex (head down) presentation during this month.

Answer 15

End of 36th Gestational Week

Question 16

• Fetus kicks actively, hard enough to cause the mother considerable discomfort.
• Fetal hemoglobin begins its conversion to adult hemoglobin. The conversion is so rapid that, at birth, about 20% of hemoglobin will be adult in character.
• Vernix caseosa is fully formed.

Answer 16

End of 40th Gestational Week (Third Trimester)