Kaplan Biology: Chapter 3 Embryogenesis Flashcards
sonic hedgehog and chemcials that induce differentiation are known as ___
morphogens
totipotent
embryonic stem cells that can differentiate into any cell type
pluripotent
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
multipotent
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.
outline the embryonic development from egg and sperm
egg + sperm –> zygote –> embryo –> morula –> blastula–> inner and outer cell masses.
inner mass becomes the 3 germ layers
outer mass becomes the placenta
inner cell mass is ____ potent
pluripotent. it gives rise to the 3 germ layers and these cells can differentiate into any cell besides the ones that form the placenta.
which cells are totipotent?
morula and embryo. the minute it becomes a blastocyst and forms the inner and outer cell masses, they become pluripotent.
____ communication is when chemicals act on the same cell that secreted the signal
autocrine
paracrine signalling
act on cells in a LOCAL area
juxtacrine signalling
cell directly stimulating receptors of the ADJACENT cell without diffusion
endocrine signalling
secreted hormones that travel through the blood stream.
reciprocal development
most tissues will be exposed to multiple inducers during the course of development
what structures does the ectoderm give rise to
skin, mouth, nervous system, neural tubes, anus
what structures does hte mesoderm give rise to
skeletomuscle system
circulatory system
excretory system
reproductive system
what structures does the endoderm give rise to
digestive tract
respiratory tract
accessory organs.
T/F: aldult cells have telomerases
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.
which types of cells have telomerases
germ cells, fetal cells, stem cells and tumors.
where does oxygenation occur in a fetus
oxygenation occurs at the placenta rather than in the fetal lungs
Why does fetal Hemoglobin have higher O2 affintiy
assists with transfer and retention of oxygen into the fetal circulatory system.
purpose of fetal shunts
to direct blood flow away from sensitive organs that are sensitive to high blood pressures. This also hinders their development though.
name the 3 shunts in the fetus
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.
oxytocin is produced in the ___ and is secreted into the bloodstream by the ___ pituitary gland
oxytocin is produced in the HYPOTHALAMUS and is secreted into the bloodstream by the POSTERIOR pituitary gland
