Lecture 17 - Reproduction

Question 1

What is preformation?

Answer 1

Embryo is preformed and grows or enlarged during development

Question 2

What is epigenesis?

Answer 2

Man arises from the successive differentiation of a formless being

• menstrual blood and semen

Question 3

What is a biopotential gonad?

Answer 3

Sexually indifferent stage in which the embryo has the potential to develop either male or female structures

Question 4

What do the Wolffian (mesonephric) ducts develop into?

Answer 4

Epididymis, ductus deferens, seminal vesicle, urethra

Question 5

What do the Mullerian (paramesonephric) ducts develop into?

Answer 5

Oviduct, uterus, cranial vagina

Question 6

What is the importance of sex differentiation?

Answer 6

Depends on the sex chromosomes X and Y

• specification of the gonad as either testes or ovaries
• SRY (Sex-determining Region of the Y chromosome)

Question 7

What variation must happen for sex differentiation?

Answer 7

Absence of SRY gene - gonads will be ovaries, anti-mullerian hormone, peptide hormone that causes the Müllerian ducts to regress (FEMALE)

With SRY gene - Anti-mullerian hormone (AMH), peptide hormone that causes the Müllerian ducts to regress

Question 8

What is a Freemartin?

Answer 8

Abnormal embryogenesis of the female reproductive tract

• Heifer born twin to a bull

Question 9

What is Oogenisis?

Answer 9

Production of female gametes, oocytes

Question 10

What is folliculogenesis?

Answer 10

Follicle maturation and ovulation

Question 11

What are functions of the ovary?

Answer 11

Oogenisis and folliculogenesis

Produce sex hormones estrogen and progesterone

Question 12

What is the function in the female reproductive tract of Gonadotropin Releasing Hormone?

Answer 12

GnRH

- released by the hypothalamus that stimulates release of LH and FSH from the anterior pituitary

Question 13

What is the function in the female reproductive tract of Luteinizing Hormone

Answer 13

LH

- stimulates estrogen production in ovary and ovulation by binding LH - receptor on the Theca cells

Question 14

What is the function in the female reproductive tract of Estrogen?

Answer 14

• Produced in the granulosa cells by conversion of testosterone to estrogen, primary targets is the reproductive tract
• induction of pre-ovulatory surge of LH, mucus production, increased blood flow, reproductive behaviors

Question 15

What is the function in the female reproductive tract of Progesterone?

Answer 15

• produced by the corpus luteum after ovulation, maintenance of pregnancy

Question 16

When is meiosis arrested and when does it resume?

Answer 16

Meiosis 1 resumes at ovulation

Meiosis 2 is completed at fertilization

Question 17

What is the process of Oogenisis?

Answer 17

• developing female embryo produces oognia
• undergo mitotic divisions up to birth, begin meiosis after birth and stop at prophase 1
• at puberty, FSH stimulates follicle growth, and reactivates meiosis
• process stops again at meiosis 2
• ovum released at ovulation is the secondary oocyte
• completion of meiosis and shedding of the last polar body may occur as late as fertilization

Question 18

What is folliculogenesis?

Answer 18

The process in which immature follicles develop into more advanced follicles and become candidates for ovulation

Question 19

What is the function of the ovary?

Answer 19

• highly vascularized: nutrient and oxygen delivery (hormones in and out)

Question 20

Theca cells

Answer 20

Have LH receptors

- stimulation of ovulation, formation of CL, progesterone secretion

Question 21

Granulosa cells

Answer 21

Line the antrum of the pre-ovulation you follicle, have FSH receptors with primary action of follicular development and estrogen synthesis

Question 22

Pre-ovulatory (tertiary) follicle

Answer 22

Characterized by fluid-filled cavity (antrium) filled with follicular fluid; have Theca and granulosa cell layers, secondary oocyte

Follicle that is ovulated

Question 23

Corpus luteum

Answer 23

Large “yellow bodies” that produce progesterone, formed from granulosa and the cal cells after ovulation

Question 24

Corpus albicans

Answer 24

White, scar-like structure that represents degenerating CL, increasing connective tissue, decreasing secretory tissue