CH3 Embryogenesis and Development

Question 1

Fertilization, where does it occur?

Sperm binding?

Acrosome RXN?

Cortical RXN?

Genetic Transfer?

Answer 1

Occurs in widest part of fallopian tube = Ampulla

1. Sperm BInding: Zona pellucida binds to the outside of the sperm
2. Acrosome Reaction: acrosomal enzyme beggin to digest the zona pellucida for the sperm to get deeper
3. Cortical Reaction: sperm and egg membrane bind release of Ca2+ (depolarises cell) = cortical granules get released and dissolve the zona pellucida (block to polyspermy)
4. Genetic Transfer: membranes fuses and DNA is released inside the egg

Question 2

Cleavage, where is the zygote traveling at this moment?

Answer 2

From fallopian tube to uterus

Cleavage:

1. Quick division without growth (still inside the zona pellucida)

after first division goes from Zygote (unicellular) to Embryo

2. After some divisions, the embryo is called a Morula (mora)

Question 3

Blastulation:

1. Types of cells found and what will they become?
2. Why is it called Blastocyst
3. Zona pellucida

Answer 3

1. Differentiation begins. Cells = Embry​oblast inside (Inner Cell Mass (IMS) that will become the fetus), Throphoplasts (will become placenta) outside layer
2. Embryoblast compact to one side (leave cavity called blastocoel). It is a Blastocyst
3. No more zona pellucida

Question 4

Gastrulation

Embryoblasts differentiate into what cells? what do they from?

Invagination Process? and form what?

Answer 4

Generation of 3 distinct cell layers:

1. Embryoblasts differentiate into Epyblast (creates amniotic cavity) and Hypoblast (will become the umbilical vesicle)
2. Invagination and differentiation of epiblast and hypoblasts form the Ectoderm, Mesoderm, Endoderm

Question 5

Neurulation

Answer 5

Question 6

Teratogens

Answer 6

Substances that interfere with development

Question 7

Morphogens

Answer 7

Substance that can induce cell determination

Question 8

STEM Cells:

• Totipotent
• Pluripotent
• Multipotent

Answer 8

Totipotent: has the greatest potency, embryonic STEM cell that can differentiation into the fetus or in placental structure

Pluripotent: Can differentiate into any cell except those in the placenta

Multipotent: multiple types of cells within a particular group. i.e hematopoietic cell can differentiate into all of the cells in the blood

Question 9

Apoptosis vs Necrosis

Answer 9

Apoptosis is suicide occurs normally

Necrosis is due to injury and can release its contents and damage neighboring cells

Question 10

The Placenta function?

how does oxygen and co2 pass

Fetal Hemoglobin (Hbf) characteristics?

Answer 10

Nutrient, gas, and waste exchange b/w the fetus and the mother. Secretes hormones (estrogen, progesterone, and hCG)

O2 and CO2 are passively exchange due to concentration gradients

Hbf has more affinity for oxygen than Hba

Question 11

Umbilical Arteries and Veins

Answer 11

Umbilical Arteries: carry deoxygenated blood

Vein: Oxygenated blood

Question 12

Fetus Development

1st, 2nd, 3rd, birth

Answer 12

1st trimester: Organogenesis (heart, eyes, gonads, limbs, liver, brain)

2nd trimester: tremendous growth, movement begins, the face looks human

3rd trimester: brain development, antibody transfer

Birth: amniotic sac ruptures, uterine contractions, coordinated by prostaglandins and oxytocin result in birth

Question 13

what do they form?

• Ectoderm
• Mesoderm
• Endoderm

Answer 13

Ectoderm: integumentary system (skin, hair, nails, exocrine glands), brain, spinal cord, pituitary gland

Mesoderm: Muscoskeletas, cardiovascular, excretory, and reproductive system

Endoderm: digestive system, liver, pancreas, bladder, thyroid, parathyroid glands, and epithelial layer of lungs