Female repro pt 3

Question 1

What are the central nervous system effects of estradiol?

Answer 1

Increase excitability of neurons in the hypothalamus that integrate other mating sensory input

Question 2

Where is removal of non-motile sperm?

Answer 2

Cervix

Question 3

What is capacitation of sperm?

Answer 3

• Removal of sterols from the membrane to make it more fluid
• Removal of glycoprotein coat to expose receptor
• Increased motility

Question 4

What happens after capacitation?

Answer 4

Occurs in waves so multiple viable sperm are available over a short window

Question 5

What are the steps to fertilization?

Answer 5

1. Binding
2. Acrosomal reaction
3. Penetration
4. Membrane fusion
5. Cortical reaction
   6.Second meiotic division
6. Pronucleus
7. Zygote formation
   9/ Morula and blastocyte formation

Question 6

What happens when sperm binds?

Answer 6

First it contacts the cumulus oophorus and then weaves through follicular cells to bind to ZP3 proteins in the zona pellucida

Question 7

What happens with acrosomal reaction?

Answer 7

Binding to ZP3 causes sperm to have a rapid increase in Ca and the acrosome fuses to the membrane and the contents are exocytosed. Contents of the acrosome digest the zona pellucida

Question 8

What happens during penetration?

Answer 8

The zona pellucida has been digested and the sperm mechanically penetrates through the zona pellucida and contacts the cell membrane

Question 9

What happens during membrane fusion?

Answer 9

Sperm head lays flat against the oocyte and microvilli grow around the head and bind causing membrane fusion. Contents of sperm head enter cytoplasm

Question 10

What happens during the cortical reaction?

Answer 10

Membrane fusion causes increase in IP3 in oocytes which increases Ca. THis causes cortical vesicles to fuse with the oocyte membrane and crosslinking of the zona pellucida to prevent polyspermy

Question 11

When are morulas formed and what is it?

Answer 11

3-7 days after fertiliazation is a circular mass of cells that enters into the uterus

Question 12

What happens to the morula?

Answer 12

Eventually forms tight junctions and fills with fluid creating a blastocyst with an inner cell mass and a trophoblast outer lyer that then hatches breaking out of the zona pellucida

Question 13

In order for successful concenption, what hormone must be present?

Answer 13

Progesterone, drops in this usually signal luteolysis so to maintain pregnancy have to prevent drops in this

Question 14

What hormones do the placenta secrete?

Answer 14

For the majority it secretes progesterone (sustain pregnancy making CL less important) and low levels of estradiol. Switching amounts induces labor