Chapter 3- Embryogenesis and Development

Question 1

earliest we can tell the sex of a baby

Answer 1

16 to 17 weeks

Question 2

ampulla

Answer 2

widest part of fallopian tube where fertilization occurs

Question 3

what happens after penetration of the sperm through the cell membrane of the egg

Answer 3

cortical reaction, a release of calcium ions (which depolarize cell preventing fertilization by multiple sperm and increases metabolic rate of newly formed diploid zygote)

Question 4

where do fertilization and implantation occur?

Answer 4

fallopian tubes- fertilization

uterus- implantation

Question 5

trophoblast cells

Answer 5

surround the blastocoel and give rise to chorion and later the placenta

Question 6

placental development

Answer 6

trophoblastic cells –> chorion (extraembryonic membrane that develops into the placenta)

Question 7

umbilical cord

Answer 7

2 arteries (carry deoxygenated blood and waste to placenta for exchange) and 1 vein (carries oxygenated blood with nutrients from placenta to embryo)

Question 8

origin of the adrenal glands

Answer 8

adrenal cortex–> mesoderm

adrenal medulla–> ectoderm (b/c it contains some nervous tissue in it as well)

Question 9

induction

Answer 9

ability of one group of cells to influence the fate of other nearby cells (process mediated by inducers)

Question 10

Teratogens

Answer 10

substances that interfere with development, causing defects or even death of the developing embryo or fetus. (ex: alcohol, drugs, viruses, bacteria, and environmental chemicals)

Question 11

what helps with neural tube closure

Answer 11

folic acid

Question 12

stage of implantation during fetal development?

Answer 12

blastula stage (must be implanted for gastrulation)

Question 13

what tissues do neural crest cells develop into?

Answer 13

PNS

Question 14

Morphogens

Answer 14

Molecules that cause determination of cells, diffuse through the organism

Question 15

apoptotic blebs

Answer 15

cell that can be digested by other cells (allows for recycling of materials)

Question 16

necrosis

Answer 16

process of cell death in which a cell dies as a result of injury (can result in internal substances being leaked causing irritation of nearby cells or an immune response)

Question 17

complete vs. incomplete regeneration

Answer 17

complete-replaced with identical tissue

incomplete-replaced with nonidentical in structure or function compared to lost tissue

Question 18

senescence

Answer 18

biological aging. at the organismal level it represents changes in the bodys ability to respond to a changing environment.

Question 19

placenta

Answer 19

where nutrients, gas, and waste exchange occurs through DIFFUSION without mixing mom and child blood types b/c they may be diff.

Question 20

fetal vs. maternal hemoglobin

Answer 20

fetal hemoglobin has a higher O2 affinity

Question 21

fetal vs. maternal organs

Answer 21

lungs (gas exchange at placenta) and liver (detoxification/metabolism in mothers liver) do not serve significant functions prior to birth

Question 22

shunts to protect fetus organs from blood that aren’t in use

Answer 22

keep blood away from…

1. lungs- foramen ovale (blocks R and L atrium connection) 2. ductus arteriosus (blocks leftover blood from pulmonary artery to aorta)
2. liver- ductus venosus (blocks blood returning from placenta via umbilical vein directly to inferior vena cava

Question 23

key events in 1st trimester

Answer 23

most organs have formed and bone is starts hardening, heart starts beating

Question 24

key events in 2nd trimester

Answer 24

growth (9cm to 30/36cm), moves, face like human

Question 25

key events in 3rd trimester

Answer 25

growth and more brain development, antibodies go from mom to fetus for protection. last organ to be fully functional are the lungs

Question 26

birth

Answer 26

rhythmic contractions (smooth muscle) by prostaglandins and oxytocin

Question 27

which layer does notochord form from

Answer 27

mesoderm

Question 28

stem cell classification

Answer 28

totipotent- can be anything including 3 germ layers and placenal cells
pluripotent- can be any of the 3 germ layers and their derivatives
multipotent- differentiate only into specific subset of cell types