Cell Bio Lecture 12 - Early Development 1 Flashcards Preview

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Flashcards in Cell Bio Lecture 12 - Early Development 1 Deck (17)
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1
Q

When is it called an embryo and when is it called a fetus?

A

0-8 weeks is an embryo, 9-38 is a fetus.

2
Q

What did thalidomide teach developmental biologists?

A

Gave them a timetable for human embryonic development

3
Q

What is gametogenesis?

A

The formation of fully-developed gametes.

4
Q

How long does it take for sperm development (spermiogenesis)?

A

Three days

5
Q

What is the site of a vasectomy?

A

The vas defrens

6
Q

What forms the acrosome of the sperm?

A

The Golgi

7
Q

What is in the mid-piece of the sperm?

A

Mitochondria

8
Q

When in a male’s lifetime are sperm produced?

A

From puberty onward.

9
Q

At what point in the cell cycle is the primary oocyte arrested?

A

Prophase I

10
Q

At what point in the secondary oocyte arrested?

A

Metaphase II

11
Q

What hormone causes ovulation?

A

LH surge

12
Q

What are the cumulus oophorus?

A

The cells that have direct cytoplasmic bridges with the mature oocyte to provide nourishment and hormones.

13
Q

Describe the process of follicle maturation.

A

GnRH stimulates FSH secretion, which stimulates 4-12 primordial follicles to grow and secrete estrogen. The fastest growing follicle secretes estrogen, which downregulates GnRH (and FSH), but because it has more FSH receptors, it wins the race. This follicle continues to mature; complete maturation takes 2-3 cycles.

14
Q

Describe the process of ovulation (when the Graafian follicle expels the secondary oocyte).

A

FSH drives estrogen levels, and when estrogen hits a threshold, LH surge happens. LH surge triggers release of the primary oocyte from prophase I, and it quickly enters meiosis II and arrests at metaphase. This is now a secondary oocyte within a Graafian follicle. Prostaglandins like PGE2 cause the follicle to rupture, and the oocyte is expelled by contraction of the smooth muscle-like theca cells.

15
Q

How long after the LH surge does ovulation occur?

A

12-24 hours

16
Q

What surrounds the secondary oocyte upon expulsion?

A

The zona pellucida and one or more layers of follicle cells called the corona radiata.

17
Q

How many primordial germ cells will females generate after birth?

A

NONE!