Third Month to Birth: The Fetus Flashcards Preview

Anatomy > Third Month to Birth: The Fetus > Flashcards

Flashcards in Third Month to Birth: The Fetus Deck (10):

When does the greatest length increase occur?

months 3, 4, and 5


When does the greatest weight increase occur?

months 8 and 9


Length of pregnancy

38 weeks (266 days) after fertilization or 40 weeks after the last menstrual period


When does the external genitalia develop?

week 12 (the sex of the fetus can be determined by ultrasound)


Highlights of 13 to 16 weeks

growth is very rapid here, limb movements are more coordinated, face becomes more human-looking, by 16 weeks the ovaries are differentiated and contain primordial follicles that have oogonia


Highlights of 17 to 20 weeks

growth slows down, movements are felt by mother, brown fat forms, testes begin to descend


Highlights of 21 to 25 weeks

substantial weight gain, secretory epithelial cells in the lung have begun to secrete surfactant, sucking movements and can react to sounds, respiratory system immature


Highlights of 26 to 29 weeks

lungs have developed sufficiently for gas exchange, CNS has matured where it can direct rhythmic breathing and control body temp., formation of red blood cells moves to bone marrow


Highlights of 30 to 34 weeks

pupillary light reflex of the eyes, 32 weeks and older typically survive if born


Highlights of 34 to 38 weeks

finishing period, circumference of head and the abdomen are approx. equal, growth slows, CRL of 36cm, CHL of 50cm, and weigh approx. 3000-3400g