ch. 3 embryology week 5-8

Question 1

week 5-8: vertabrae adult body plan is established

Answer 1

-tube within a tube embryo
-bilateral symmetry
-segmentation
-notochord
-dorsal hollow nerve chord

Question 2

week 5-8:
-series of changes that result in human appearance

Answer 2

-limb buds grow to form extremities with digits
-head enlarges
-eyes, ears, nose appear
-facial appearance changes
-tail gradually disappears at week 8
-all major organs are formed

Question 3

fetal period: months 3-9
3 months

Answer 3

head dominates, while the body is elongating, ex can be determined, blood cell formation in the bone marrow

Question 4

fetal period: months 3-9
4 months

Answer 4

sucking motions of the lips occur, bones and joint cavities are distinct

Question 5

fetal period:
5 months

Answer 5

first forward bending into the fetal position, eyelashes and eyebrows are present, quickening occurs

Question 6

fetal period
6-7 months

Answer 6

eyes open cerebrum grows, increases in body size

Question 7

fetal period
8-9 months

Answer 7

fat accumulates under the skin in the hypodermis, body continues to increase in length and weight

Question 8

birth defects: causes

Answer 8

occur due to exposure to genetics or exposure to teratogens

Question 9

genetics:

Answer 9

occur in week 0-1 at fertilization

Question 10

embryo is most susceptible to birth defects at

Answer 10

week 5
-all organ systems are trying to be established

Question 11

environment

Answer 11

affected at week 2, until implantation