Kaplan Biology: Chapter 3 Embryogenesis

Question 1

sonic hedgehog and chemcials that induce differentiation are known as ___

Answer 1

morphogens

Question 2

totipotent

Answer 2

embryonic stem cells that can differentiate into any cell type

Question 3

pluripotent

Answer 3

germ cells that can differentiate into any cell type EXCEPT those found in the placental structures. Ie/ germ cells that can differentiate into any “bodily’ cell

Question 4

multipotent

Answer 4

stem cells that can differentiate into multiple types of cells within a particular group.

ex/ hemopoietic stem cells are cells that are capable of differentiating into all the cells found in the blood (white, red, lukocytes, megakaryocytes.

Question 5

outline the embryonic development from egg and sperm

Answer 5

egg + sperm –> zygote –> embryo –> morula –> blastula–> inner and outer cell masses.

inner mass becomes the 3 germ layers
outer mass becomes the placenta

Question 6

inner cell mass is ____ potent

Answer 6

pluripotent. it gives rise to the 3 germ layers and these cells can differentiate into any cell besides the ones that form the placenta.

Question 7

which cells are totipotent?

Answer 7

morula and embryo. the minute it becomes a blastocyst and forms the inner and outer cell masses, they become pluripotent.

Question 8

____ communication is when chemicals act on the same cell that secreted the signal

Answer 8

autocrine

Question 9

paracrine signalling

Answer 9

act on cells in a LOCAL area

Question 10

juxtacrine signalling

Answer 10

cell directly stimulating receptors of the ADJACENT cell without diffusion

Question 11

endocrine signalling

Answer 11

secreted hormones that travel through the blood stream.

Question 12

reciprocal development

Answer 12

most tissues will be exposed to multiple inducers during the course of development

Question 13

what structures does the ectoderm give rise to

Answer 13

skin, mouth, nervous system, neural tubes, anus

Question 14

what structures does hte mesoderm give rise to

Answer 14

skeletomuscle system
circulatory system
excretory system
reproductive system

Question 15

what structures does the endoderm give rise to

Answer 15

digestive tract
respiratory tract
accessory organs.

Question 16

T/F: aldult cells have telomerases

Answer 16

false. adults do not have telomerases to replicate the telomeres, which is why our cells experience scensence and undergo apoptosis after a certain amount of divisions.

Question 17

which types of cells have telomerases

Answer 17

germ cells, fetal cells, stem cells and tumors.

Question 18

where does oxygenation occur in a fetus

Answer 18

oxygenation occurs at the placenta rather than in the fetal lungs

Question 19

Why does fetal Hemoglobin have higher O2 affintiy

Answer 19

assists with transfer and retention of oxygen into the fetal circulatory system.

Question 20

purpose of fetal shunts

Answer 20

to direct blood flow away from sensitive organs that are sensitive to high blood pressures. This also hinders their development though.

Question 21

name the 3 shunts in the fetus

Answer 21

2 shunts for lungs;

1) foramen ovale. valve that connects the right atrium to the left atrium, diverting blood from the right ventricle and preventing it from circulating in the pulmonary tract
2) ductus arteriosus: shunts left over blood from the pulmonary artery to the aorta

1 shunt for liver:
1) ductus venosus: shunts blood returning from the placenta via the umbilical vein DIRECTLY to the inferior vena cava.

Question 22

oxytocin is produced in the ___ and is secreted into the bloodstream by the ___ pituitary gland

Answer 22

oxytocin is produced in the HYPOTHALAMUS and is secreted into the bloodstream by the POSTERIOR pituitary gland