Pregnancy

Question 1

What protective layer covers the secondary oocyte?

Answer 1

corona radiata (formed from granulosa cells)

Question 2

Oocyte activation

Answer 2

Intact sperm contacts zona pellucidum
- Digestive enzymes

Fusion of oocyte and sperm membrane

Question 3

Fusion of oocyte and sperm membrane process

Answer 3

Depolarization of oocyte
- Na+ and Ca+2

Completion of meiosis II
- Ovum

Hardening of zona pellucidum (acrosome has no effect)
- Polyspermy (no multiple sperm/fertilization)

Question 4

What forms 30 hrs after amphimixis?

Answer 4

blastomeres

Question 5

Amphimixis

Answer 5

sexual reproduction involving the fusion of two different gametes to form a zygote.

Question 6

Blastocyst formation

Answer 6

Pre-embryo continues to divide

Moves through fallopian tube

Muscular contractions and cilia

Arrives at uterus ~ day 4
- Morula (is solid)

~ day 6 form blastocyst

Question 7

Blastocyst characteristics

Answer 7

Hollow
Trophoblast (outer layer)
Blastocoel (fluid-filled cavity)
Inner cell mass

Question 8

Implantation Day 7 & 9

Answer 8

Day 7, blastocyst contacts uterine wall
- Trophoblast digests (embeds) into uterine lining (troph- = food/nutrition)

Day 9, blastocyst surrounded by endometrium (completely embedded)
- Formation of amniotic cavity

Question 9

Eptopic pregnancies occur during what stage of pregnancy?

Answer 9

implantation

Question 10

Uterine glands

Answer 10

Nutrition provided by uterine glands

Question 11

Human chorionic gonadotropin (hCG)

Answer 11

Maintains corpus luteum

Question 12

Gastrulation

Answer 12

the blastocyst is reorganized into a multilayered structure known as the gastrula
- forms third layer

Question 13

Implantation: Day 12-15

Answer 13

• Gastrulation
• Formation of germ layers
  - Ectoderm, mesoderm and endoderm

Question 14

Yolk sac:

Answer 14

• formed from endoderm and mesoderm
• blood cell formation

Question 15

Amnion:

Answer 15

• fromed from ectoderm and mesoderm
• amniotic fluid

Question 16

Allantois:

Answer 16

• formed from endoderm and mesoderm
• bladder formation

Question 17

Chorion:

Answer 17

• Formed from mesoderm and trophoblast
• Nutrient transfer
• Chorionic blood vessels and villi
• Formation of placenta

Question 18

What occurs during the First Trimester?

Answer 18

Implantation
Gastrulation
Embryogenesis
Organogenesis

Question 19

What occurs during the Second Trimester?

Answer 19

• Growth
• Further organ development

Question 20

What occurs during the Third Trimester?

Answer 20

• Organs prepare for functioning
• Large weight gain

Question 21

Maternal compensations

Answer 21

Breathing rate and tidal volume increases

Blood volume increases

Nutritional requirements increase 10-30%

Increased GFR

Uterus increase in size

Mammary gland increase in size
- Secretion of products

Question 22

What factors initiate labor?

Answer 22

• Placental estrogens
  - Increase smooth muscle sensitivity
• Relaxin
• Stretch of myometrium
  - Fetal growth
• Fetal oxytocin
• Positive feedback cycle

Question 23

How is smooth muscle sensitivity increased?

Answer 23

Contraction

Oxytocin: causes contractions

Question 24

What are the effects of relaxin during labor?

Answer 24

Relaxing pubic symphysis

Dilates cervix

Question 25

Labor: Positive feedback cycle

Answer 25

Increases frequency and strength of uterine contractions

Question 26

What are the three stages of Labor?

Answer 26

Dilation stage Expulsion stage Placental stage

Question 27

Dilation stage

Answer 27

Start of contractions Fetus shifts towards canal Rupture of membranes - "breaking water"

Question 28

Expulsion stage

Answer 28

Dilation complete Strongest contractions - Lengthen and come closer together Delivery

Question 29

Placental stage

Answer 29

Contractions and shrinkage of uterus tears placenta Afterbirth