WK1 - Development of Body Form: Zygote to Embryo

Question 1

obstetrical age

Answer 1

time elapsed since last menstrual period (a time that actually precedes contraception

Question 2

gestational age

Answer 2

time elapsed since ovulation

gestational age = embryonic age + 2 weeks

Question 3

pre-embryonic period

Answer 3

1 to 2 weeks

Question 4

embryonic period

Answer 4

next 6 weeks

Question 5

fetal period

Answer 5

week 9 to 39

Question 6

trimesters

Answer 6

first, second and third - 3 months each

Question 7

where does fertilization occur?

Answer 7

high up in the fallopian tube

Question 8

what is the function of zona pellucida

Answer 8

• prevents polyspermy

- prevents implantation - lost by blastocyst

Question 9

what stage does implantation occur?

Answer 9

blastocyst stage - about the time the epiblast and hypoblast layers are forming

Question 10

what is ectopic pregnancy

Answer 10

implantation outside of uterus

Question 11

what is a primitive streak

Answer 11

region where cells are detaching from epiblast layer - migrating in

Question 12

ectoderm gives rise to:

Answer 12

• CNS
• PNS
• epidermis of skin
• teeth
• neural crest cells

Question 13

mesoderm gives rise to:

Answer 13

• bone and cartilage
• blood
• dermis of skin
• kidneys and ureters
• genital system (internal parts)
• muscles

Question 14

endoderm gives rise to:

Answer 14

• lining of digestive tract/GI tube
• liver
• pancreas (except the islets)
• urinary bladder (part)
• lungs

Question 15

define notocord and its role

Answer 15

• formed from mesoderm, which has passed through the primitive node and primitive pit
• primary inducer: induces the rest of the embryo to form

Question 16

somite mesoderm gives rise to:

Answer 16

• vertebral column - vertebrae dermis of skin
• back muscles
• muscles of body wall and limbs

Question 17

lateral plate mesoderm splits to form:

Answer 17

somatic and splanchnic layers

Question 18

somitic mesoderm gives rise to:

Answer 18

peritoneum and pleura

Question 19

splanchnic mesoderm givers rise to:

Answer 19

mesentaries muscle of the GI tract

Question 20

intermediate mesoderm gives rise to:

Answer 20

urinary and genital systems

Question 21

septum transversum gives rise to:

Answer 21

diaphragm

Question 22

describe the process of neurulation

Answer 22

• formation of the nervous system induced by the notochord
• region of the ectoderm over notocord thickens
• neural plate formed
• neural plate rolls up to form the neural tube
• neural crest formed covered by ectoderm