1.6 Reproduction

Question 1

Are sperm and oocytes haploid or diploid?

Answer 1

Haploid

Question 2

What are haploid gamete cells derived from?

Answer 2

Primordial germ cells

Question 3

When are PGC’s set aside?

Answer 3

(Primordial germ cells)
3 weeks post fertilization
-Migrate from yolk sac to genital ridge

Question 4

What does the protein encoded by SRY gene do?

Answer 4

Signals the cells around the germ cells to begin producing the steroid hormone testosterone

Question 5

What does testosterone do in reproductive development?

Answer 5

Tells the boy’s gonad to develop into a testicle, and tells cells elsewhere in the body to begin growing a penis and male brain

Question 6

How does female reproductive development occur?

Answer 6

Lack of testosterone leads to female development by default: ovaries, uterus, vagina

Question 7

When are individuals with XY externally female?

Answer 7

When there is a mutated testosterone receptor

Question 8

What triggers puberty?

Answer 8

The hypothalamus pumps out GnRH

Question 9

What are the two goals of male reproduction?

Answer 9

Producing mature gametes and delivering the gametes

Question 10

What is involved with delivering the gametes?

Answer 10

Erection, emission, ejaculation

Controlled by the autonomic nervous system

Question 11

Reproductive hormone regulation

Answer 11

GnRH from hypothalamus
FSH and LH from anterior pituitary
Inhibin and testosterone

Question 12

What does inhibin do?

Answer 12

Inhibits FSH release

Peptide hormone

Question 13

What does testosterone do?

Answer 13

• Supports sperm formation
  -Secondary sexual characteristics
  (Also inhibits GnRH, FSH and LH)

Question 14

What 3 hormones are required for spermatogenesis?

Answer 14

FSH, LH and testosterone

Question 15

Pulsatile GnRH release from hypothalamus does what?

Answer 15

Stimulates FSH and LH release from pituitary

Question 16

What is the difference in GnRH release in men and women?

Answer 16

Women have surges of GnRH and changes on a monthly basis, men do not

Question 17

What does constant (non-pulsatile) GnRH infusion do?

Answer 17

Shuts down LH secretion from gonadotropes

Question 18

What do leydig cells do?

Answer 18

Interstitial, steroidgenic cells produce testosterone in response to LH stimulation

Question 19

Sertoli Cells

Answer 19

Sustentacular cells

• Support spermatogenesis in response to FSH & testosterone stimulation
• Produce inhibin
• Produce some estrogen

Question 20

Spermatogonia

Answer 20

Diploid, 46 chromosomes
Bona fide stem cells (multipotent) undergoing mitosis and self renewal
One daughter cell enter meiosis to reduce chromosome # to 23

Question 21

Sperm-motile cell

Answer 21

Bears either X or Y chromosome, must mature in epididymis

Question 22

Where is sperm stored?

Answer 22

Epididymis

Question 23

What is the vas deferens?

Answer 23

Smooth muscle surrounding ducts

Question 24

Secondary effects of testosterone

Answer 24

• Maintains muscle mass and bone density
• Maintains remainder of “male plumbing”
• Kills off verbal communication neurons-increased aggression behaviors

Question 25

Goals of Female Reproductive System

Answer 25

1. Nurturing & Releasing gametes - eggs (oocytes)

2. Supporting the potential embryo (fetus)

Question 26

What is a follicle?

Answer 26

Oocyte (gamete) surrounded by support cells

Question 27

Follicle stages

Answer 27

Primordial
Primary
Secondary
Tertiary (Vesicular or Graafian)
-->Estrogen

Question 28

Following ovulation, the follicle becomes..

Answer 28

Corpus luteum–> Progesterone & Estrogen

Question 29

Theca cells

Answer 29

Respond to LH, produce androgen precursors to estrogen, become small luteal cells in corpus luteum
-Female equivalent of leydig cells

Question 30

Granulosa cells

Answer 30

Respond to FSH, express aromatase enzyme to convert androgens to estrogens; become large luteal cells in corpus luteum

Question 31

Oocytes: meiosis

Answer 31

Stuck in meiosis I for majority of woman’s life, paracrine communication with granulosa; estrogen–> GnRH–> LH surge restarts meiosis

Question 32

Hormonal control in females

Answer 32

GnRH–> LH, FSH–>Estradiol (E2), Progesterone (P4), Inhibin

Question 33

Two phases of the female cycle

Answer 33

Ovarian and Uterine (menstrual)

Question 34

What is the dividing point of the two female cycles?

Answer 34

Ovulation

Question 35

Human Chorionic Gonadotropin

Answer 35

Made by the fetal placenta, “rescues” the corpus lute from destruction during luteolysis

Question 36

Follicular Stage of Ovarian cycle

Answer 36

• FSH surge stimulates new follicular wave
• Follicle selection
• LH and FSH stimulate higher and higher levels of estrogen