Ch 29 A Pregnancy

Question 1

What are the cell stages of preembryo?

Answer 1

Zygote-fertilized cell (1st diploid cell)
Blastomere-first mitotic div (2-8 cells)
Morula-solid mass of cells (16-100)
Blastocyst-hollow sphere with 100+ cells (This implants into endometrium)

Question 2

What occurs in embryo stage?

Answer 2

Organogenesis-development of tissues into organs. All present before next phase (8 weeks)

Question 3

During fertilization what protects the egg from infection?

Answer 3

Corona Radiata and zona pellucidum

Question 4

What is capacitation?

Answer 4

activation/destabilization of the acrosome. Necessary for sperm to be able to burrow through corona radiate and zona pellucidum.

Question 5

What is Human Chorionic Gonadotropin (hCG)?

Answer 5

Hormone produced by fertilized cell maintaining corpus luteum secreting progesterone (instead of losing into menstrual cycle) until placenta takes over.

Question 6

What gives rise to the placenta?

Answer 6

Trophoblast become chorion and then placenta. Chorionic villi grow into endometrium and become immersed in maternal blood w/o mixing with fetus.

Question 7

What is the function of the blood testes barrier?

Answer 7

Keeping the immune system out of seminiferous tubules since sperm are non self. this prevents antibodies from destroying sperm rendering man sterile.

Question 8

What is Gastrulation?

Answer 8

converts the blastula into a gastrula and develops 3 germ layers.

Question 9

What are the 3 germ layers and the assoc. developed systems?

Answer 9

Endoderm-digestive, respiratory, urogenital systems
Mesoderm-connective tissue and muscles
Ectoderm-nervous system and epidermis

Question 10

What are the stages of conceptus?

Answer 10

Preembryo-0-2 weeks
Embryo-2-8 weeks
Fetus-9 weeks to birth (40)

Question 11

Name and define the embryonic membranes.

Answer 11

Amnion-provides environment for fetus/embryo to grow, maintains temperature
Yolk sac-forms beginnings of digestive system
Allantois-forms base of umbilical cord and urinary bladder
Chorion-surrounds all membranes and forms placenta

Question 12

What is chadwicks sign?

Answer 12

darkening of vagina due to increased blood flow during pregnancy

Question 13

What is Lordosis?

Answer 13

Exaggerated lumbar spinal curvature from increased abd weight.

Question 14

What are the hormones of the placenta?

Answer 14

Estrogen
Progesterone
Human Placental Lactogen
Human Chorionic Thyrotropin
Relaxin

Question 15

What stimulates uterine smooth muscle to become more responsive to ________ and ________ as delivery approaches.

Answer 15

Oxytocin
Oxytocin
Prostaglandins

Question 16

What are the 3 periods of dilation?

Answer 16

Cervical dilation:0-10 cm
Engagement-head enters true pelvis and presses against the cervix
Water breaks-amnion ruptures releasing its fluid