LAB 9

Question 1

zygote

Answer 1

fertilized egg (after fertilization) 
back to 46 chromosomes (2n)

Question 2

Blastomere

Answer 2

A cell formed

Question 3

Morula

Answer 3

16-cell stage

Question 4

Blastocyst

Answer 4

forms a blastocele

entered uterus ready for implantation

Question 5

Inner cell mass

Answer 5

face endometrium and become embryo

Question 6

Trophoblast

Answer 6

become placenta

Question 7

Blastocele

Answer 7

embryonic cavity

Question 8

syncytiotrophoblast

Answer 8

perimeter

Question 9

what enzyme is secreted to erode the endometrium?

Answer 9

hyulronidase

Question 10

Cytotrophoblast

Answer 10

interior of trophoblast retaining cell boundaries

Question 11

Chorionic villi

Answer 11

extend into maternal blood filled lacunae

becomes placenta

Question 12

embryonic disc

Answer 12

superficial, forms amniotic cavity

Question 13

endoderm

Answer 13

forms amniotic cavity

Question 14

ectoderm

Answer 14

forms yolk sac

Question 15

Amnion (amniotic cavity)

Answer 15

cushions developing embryo and fetus

room for growth

Question 16

yolk sac

Answer 16

nutrient source for internal cell mass

stem cells for testes, ovaries, and blood

Question 17

primitive streak

Answer 17

raised dorsal groove establishes longitudinal axis of embryo

Question 18

Mesoderm

Answer 18

middle germ layer

Question 19

Allantois

Answer 19

eventually become umbilical cord and urinary bladder

Question 20

Chorion

Answer 20

transit system for blood and nutrients

Question 21

how long is the human gestational period (from federalization to parturition)?

Answer 21

9 months

38 weeks

Question 22

how long is it if you calculate from the last menstrual period?

Answer 22

40 weeks

Question 23

What is the term for rapid mitotic cell division without cell growth?

Answer 23

cleavage

Question 24

what hormone is secreted by trophoblast?

Answer 24

human chorionic gonadotropin (HCG)

Question 25

which part of the blastocyst will become the embryo?

Answer 25

inner cell mass

Question 26

where are the embryonic blood cells made?

Answer 26

yolk sac

Question 27

explain why the corpus lutuem does not degenerate if an embryo implants into the uterus?

Answer 27

HCG maintains corpus luteum which continues to secrete progesterone which quiets the utterers

Question 28

gastrulation

Answer 28

formation of germ layers

Question 29

list the structures that are formed by ectoderm

Answer 29

• nervous and skeletal system

- epidermis

Question 30

list the structures that are formed by mesoderm

Answer 30

• muscle

- cartilage

Question 31

list the structures that are formed by endoderm

Answer 31

• GI tract
• urinary bladder
• urethra

Question 32

when is the placenta fully formed?

Answer 32

8th week

Question 33

umbilical vessels:

1. two arteries
2. one vein

Answer 33

1. deoxygenated

2. oxygenated

Question 34

5 hormones secreted by placenta

Answer 34

hCG
hPL
Relaxin
Progesterone/ estrogen

Question 35

HCG

Answer 35

maintain corpus luteum

Question 36

HPL

Answer 36

prepares mammary glands for milk production

Question 37

Relaxin

Answer 37

increases flexibility of pubis, cervix, vaginal canal.

surpasses release of oxytocin until labor

Question 38

Progesterone/estrogen

Answer 38

maintenance of endometrial lining

Question 39

foramen ovalis becomes

Answer 39

fossa ovalis

Question 40

ductus arterioles becomes

Answer 40

ligamentum arteriosum after birth