Embryogenesis and Development

Question 1

List the 5 steps of embryogenesis

Answer 1

1. ) Fertilization
2. ) Morula
3. ) Blastula
4. ) Gastrulation
5. ) Neurulation

Question 2

Describe the process of fertilization.

Answer 2

Occurs in the Ampulla of fallopian tube.
Sperm’s Acrosomal enzymes penetrate
corona radiate & zona pellucia.
Acrosomal enzymes inject pronucleus.
Cortical reaction releases Ca2+ which
depolarizes ovum membrane and makes
it impenetrable.

Question 3

What is the morula?

Answer 3

Early, solid mass of cells`

Question 4

Where does the blastula implant?

Answer 4

• Implants in endometrial lining
• Fluid filled blastocoel
• Trophoblast –> Chorion / placenta
• Inner Cell Mass –> Organism

Question 5

When does the ectoderm, mesoderm and endoderm develop?

Answer 5

Gastrulation

Question 6

Ectoderm:

Answer 6

Nervous system, skin, hair, nails, mouth, anus.
“Atract-oderm”: Skin, hair are things people are attracted to.

Question 7

Mesoderm:

Answer 7

Muscoskeleton, circulatory system, gonads, adrenal cortex.
“Move-oderm”: Involved in moving things such as muscles, RBC, steroids

Question 8

Endoderm

Answer 8

Endocrine glands, GI tract, respiratory tract, bronchi, bladder, stomach.
“In-doderm”: Things that are inside.

Question 9

Describe the process of neurulation

Answer 9

Mesoderm develops a Notochord. Notochord induces Ectoderm.

Ectoderm –> Neural folds ——-> Neural tube-→ central nervous system

Ectoderm-→ Neural folds -→ Neural Crest cells -→ Peripheral nervous system

Question 10

What are totipotent stems cells?

Answer 10

Totipotent: “Total”, can be any type of cell

Question 11

What are pluripotent stem cells?

Answer 11

Pluripotent: Can be any cell except those found in placental structures

Question 12

Multipotent stem cells

Answer 12

Multipotent: More specialized. Can be multiple types of cells

Question 13

How is fetal hemoglobin different then adult hemoglobin?

Answer 13

Fetal Hemoglobin (HbF): higher ­O2 affinity than HbA O2 and CO2 exchange via diffusion

Question 14

Define determination in terms of cell specialization.

Answer 14

Cell commits to becoming a certain type of cell

Question 15

Define differentiation in terms of cell specialization

Answer 15

Follows determination. Selectively transcribe genes appropriate for cell’s specific function

Question 16

Define induction.

Answer 16

Group of cells influence the fate of nearby cells. Mediated by inducers, which are commonly growth factors.

Question 17

Define autocrine cell signaling.

Answer 17

Self signaling cell

Question 18

Paracrine in cell signaling

Answer 18

Signal’s another cell

Question 19

Juxtacrine cell signaling

Answer 19

signal neighboring cell