pregnancy and embryonic development. fertilization oocyte is viable for 12 to 24 hours after it is...
TRANSCRIPT
Pregnancy and Embryonic Development
Fertilization
• Oocyte is viable for 12 to 24 hours after it is cast out of the ovary
• Sperm generally retain their fertilizing power within the female reproductive tract for 12 to 48 hours
• It takes 1 to 2 hours for sperm to complete the journey up the female duct system
Fertilization
• After sperm entry, changes occur in the fertilized egg to prevent other sperm from gaining entry
• Fertilization occurs at the moment the genetic material of a sperm combines with that of an ovum to form a zygote
• The zygote represents the first cell of the new individual
Fertilization(conception) video
• https://www.youtube.com/watch?v=BFrVmDgh4v4
Cleavage provides large number of cells to serve as building blocks A solid ball of
Blastomeres (a type of cell)
Morula hollows out and fills with fluid
Human Development Video
• https://www.youtube.com/watch?v=UgT5rUQ9EmQ
Fetal Development • Once the embryo is planted in the
uterus, the blastocyst develops elaborate projections called chorionic villi,
- Chorionic villi will operate with the tissues of the mother’s uterus to form the placenta
• Once the placenta is formed, the embryonic body is surrounded by a fluid-filled sac called the amnion
- The amnion is attached to the placenta by umbilical cord
How a baby develops video
• https://www.youtube.com/watch?v=h82ltr84_Yg&feature=youtu.be&src_vid=KXRbV33J5qk&feature=iv&annotation_id=annotation_2692649789
Childbirth
• Also called parturition• It usually occurs within 15 days of the calculated due date• The series of events that expel the infant from the uterus
are referred to collectively as labor• Cause of labor: high level of estrogen in the mother’s
blood- Abundant oxytocin (hormone) receptors in the
myometrium - Interfere with progesterone's quieting influence on the
uterine muscle• False labor: Braxton Hicks contraction, weak irregular
uterine contractions
Stages of Labor
• Stage 1: Dilation Stage- Time from the appearance of true contractions
until the cervix is fully dilated by the baby’s head ( about 10 cm in diameter)
- Contractions gradually become stronger- As the infant’s head is forced against the cervix,
the cervix begins to soften and becomes thinner and dilates
- Eventually, the amnion rupture- Longest part of labor, usually last 6 to 12 hours
Stages of Labor
• Stage 2: Expulsion Stage- The period from full dilation to delivery of the infant- It last typically 50 min. in a first birth and around 20
min. in subsequent births- The head will be delivered first- After birth, the umbilical cord is clamped and cut• Stage 3: Placental Stage- It is the delivery of the placenta- Usually within 15 min after birth of the infant