chapter 29 human development and aging

Question 1

the study of prenatal development

Answer 1

embryology

Question 2

examines changes in form and function from fertilized egg through old age

Answer 2

developmental b iology

Question 3

some authorities assert that the fertilized egg or the two-cell stage is an

Answer 3

embryo

Question 4

other authorities (including this textbook) say that an individual becomes and __ when it is 16 days old and consists of 3 primary germ layers

Answer 4

embryo

Question 5

germ layers of an embryo

Answer 5

endoderm (inner), mesoderm(middle) , and ectoderm(outer)

Question 6

the first 16 days after fertilization

Answer 6

preembryonic stage

Question 7

process that migrating sperm must undergo to make it possible to penetrate an egg

Answer 7

capacitation

Question 8

combines the haploid set of sperm chromosomes with the haploid set of egg chromosomes producing a diploid set

Answer 8

fertilization

Question 9

fertilization by two or more sperm which would produce a doomed fertilized egg

Answer 9

polyspermy

Question 10

two mechanisms to prevent polysmery

Answer 10

fast block and slow block

Question 11

binding of the sperm to the egg opens Na+ channels in egg membrane

Answer 11

fast block

Question 12

involves secretory vesicles, cortical granules, just below membrane; releases an inflow of Ca2+

Answer 12

slow block

Question 13

when sperm encounters an egg, it undergoes an __ reaction-excytosis of the acrosome, releasing the enzymes needed to penetrate the egg

Answer 13

acrosomal

Question 14

__ of many sperm are released to clear a path for the one that will penetrate the egg

Answer 14

enzymes

Question 15

two acrosomal enzymes

Answer 15

hyaluronidase and acrosin

Question 16

digests the hyaluronic acid that binds granulosa cells together

Answer 16

hyaluronidase (acrosomal enzyme)

Question 17

protease similar to trypsin

Answer 17

acrosin (acrosomal enzyme)

Question 18

from fertilization of egg through 12 weeks- more than half of embryos die due to chromosomal defects

Answer 18

first trimester

Question 19

weeks 13 through 24, organs complete, fetus looks kinda human

Answer 19

second trimester

Question 20

week 25 to birth- fetus grows rapidly and can survive outside of womb

Answer 20

third trimester

Question 21

at 35 weeks and 5.5 pounds, fetus is considered

Answer 21

mature