Chapter 3 Embryogenesis

Question 1

What is Cleavage

Answer 1

Cleavage, in this context, is referred to as the rapid mitotic division that a zygote undergoes as it travels from the fallopian tube to the uterine wall (endometrium).

Question 2

Blastula

Answer 2

A blastula is a morula with a cavity in the middle. At this point, there are 2 cell types: the inner-cell mass and the trophoblasts that will eventually form the chorion.

Question 3

What is the oxygenation status of umbillical arteries?

Answer 3

Umbillical arteries are carrying blood away from the FETUS, not the mother. Therefore, the blood is deoxygenated and going toward the placenta to receive oxygen.

Question 4

Mother and fetal blood do not mix; instead a diffusion matrix is formed whereby nutrients and oxygen transport solely by diffusion. What are 2 ways that the fetus has evolved to increase oxygen and nutrients from the mother?

Answer 4

1) Oxygen affinity in fetal blood is higher; there’s a different type of hemoglobin HbF.
2) A number of SHUNTS that reduces blood flow to fetal organs that aren’t being used (lung and liver)

Question 5

Germ layers

Answer 5

Ectoderm, mesoderm, endoderm

Question 6

3 types of tissue that the ectoderm creates

Answer 6

Hair, nails, and nervous tissue

Question 7

3 types of tissue that the mesoderm creates

Answer 7

Muscular systems, circulatory, bone

Question 8

3 types of tissue that the endoderm creates

Answer 8

Lung tissue, digestive tract lining, (epithelial linings) etx

Question 9

4 types of cell-cell communication and their means of function

Answer 9

1) Autocrine - cell is both inducer & responder
2) Paracrine - over nearby distances
3) Juxtacrine - direct cell contact
4) Endocrine - over long distances

Question 10

Difference between apoptosis and necrosis

Answer 10

Apoptosis involves programmed cell death and no harm to neighbors, allowing for the remnants to be digested by other cells
-Necrosis is unintentional death and may result in release of toxic enzymes, harming cells

Question 11

Name the 3 shunts in fetal development and their function

Answer 11

1) Foramen ovale - shunts blood from LV to RA, connecting the two, diverting blood from pulmonary artery.
2) Ductus arteriosus - shunts blood from pulmonary artery to aorta
3) Ductus venosus - bypasses liver by connecting umbillical vein to inferior vena cava