b3

Question 1

fertilization step 1

Answer 1

Sperm cells release enzymes from acrosome cap to digest the egg’s outer coating.

Question 2

fertilization step 2

Answer 2

Sperm move closer through the coating to the plasma membrane.

Question 3

fertilization step 3

Answer 3

Egg’s plasma membrane depolarizes after one sperm enters, blocking others.

Question 4

fertilization step 4

Answer 4

Sperm and egg nuclei fuse, forming a zygote with 46 chromosomes.

Question 5

Hormonal Contraception Mechanism

Answer 5

Inhibits Ovulation: E & P inhibit FSH and LH.

Question 6

Cervical Mucus

Answer 6

Thickens mucus: Progesterone makes it harder for sperm to swim through the cervix.

Question 7

Endometrial Lining

Answer 7

Alters lining: Progesterone changes the lining, reducing chances of implantation.

Question 8

Tubal Ligation

Answer 8

-Prevents eggs from traveling from ovaries to uterus.
-Blocks sperm from fertilizing the egg.

Question 9

Vasectomy

Answer 9

Vas deferens are cut and sealed, stopping sperm transport.

Question 10

Cleavage

Answer 10

Equal division without size increase.

Question 11

Morula (16 cells):

Answer 11

Formed ~3 days post-fertilization.

Question 12

Blastocyst (day 5)

Answer 12

Hollow ball; outer cells form extra embryonic structures, inner forms embryo.

Question 13

implantation

Answer 13

• 5–7 days after fertilization.
  -Blastocyst attaches to endometrium; trophoblast secretes enzymes for embedding.
  -Implantation completed by day 10–14.

Question 14

Hormonal Maintenance During Pregnancy

Answer 14

-hCG (from trophoblast): Maintains corpus luteum, preventing menstruation.
-Placenta takes over hormone production by 12 weeks.

Question 15

Amnion

Answer 15

Protects with fluid.

Question 16

chorion

Answer 16

Secretes hCG, facilitates nutrient/waste exchange.

Question 17

Allantois

Answer 17

Basis for umbilical cord.

Question 18

Yolk sac

Answer 18

Early red blood cells and digestion support.

Question 19

placenta

Answer 19

Facilitates gas, nutrient, and waste exchange between mother and fetus.

Question 20

what does placenta produce

Answer 20

progesterone and estrogen by 3rd month.

Question 21

Gastrulation

Answer 21

Inner mass flattens into 3 layers:

Question 22

Endoderm

Answer 22

Digestive, respiratory, endocrine.

Question 23

Mesoderm:

Answer 23

Muscles, skeleton, reproductive organs.

Question 24

Ectoderm

Answer 24

Nervous system, skin.

Question 25

First Trimester

Answer 25

Heart, brain, limb buds form; organs begin development.

Question 26

Second Trimester

Answer 26

Organ growth, skeletal hardening, reproductive organs mature.

Question 27

Third Trimester

Answer 27

Rapid growth, organ maturation, immune system development.

Question 28

Teratogens

Answer 28

-Substances affecting development: alcohol, drugs, radiation.
-Can cross placenta and harm embryo/fetus.

Question 29

Dilation

Answer 29

Cervix thins, amnion bursts (“water breaking”).

Question 30

Expulsion

Answer 30

Uterine contractions deliver baby.

Question 31

Placental

Answer 31

Placenta expelled after birth.

Question 32

Hormones involved during birth

Answer 32

Oxytocin, prostaglandins, relaxin.

Question 33

Lactation - prolactin

Answer 33

Stimulates milk production.

Question 34

lactation - Oxytocin

Answer 34

: Ejects milk and contracts uterus.

Question 35

lactation - milk

Answer 35

Milk contains antibodies; initial secretion is colostrum (no fat)

Question 36

Benefits of Breastfeeding

Answer 36

-improves immunity in babies.
-Reduces risks of certain cancers in mothers.