Chapter 4 - Reproduction and Development

Question 1

What reproductive hormone is released from the hypothalamus to the anterior pituitary?

Answer 1

gonadotropin releasing hormone (GnRH)

Question 2

What gonadotropin hormones are released from the anterior pituitary to the gonads?

Answer 2

• luteinizing hormone (LH)
• follicle stimulating hormone (FSH)

Question 3

What are the male and female gonads?

Answer 3

testes and ovaries

Question 4

What are the two responses of the gonads to gonadotropins?

Answer 4

• production of steroid hormones
• production of germ cells

Question 5

What are the germ cells in males and females?

Answer 5

spermatazoa and ova

Question 6

Define spermatogenesis

Answer 6

production of sperm

Question 7

What are the spermatogenic cells called that are closest to the basement membrane of the seminiferous tubule and how many chromosomes do they have?

Answer 7

spermatogonia - 46 chromosomes

Question 8

What is the product of the mitotic division of the first spermatogenic cells and how many chromosomes do they have?

Answer 8

two primary spermatocytes - 46 chromosomes each

Question 9

What is the product of the first meiotic division of spermatogenic cells and how many chromosomes do they have?

Answer 9

2 secondary spermatocytes - 23 chromosomes each

Question 10

What is the product of the second meiotic division of spermatogenic cells and how many chromosomes do they have?

Answer 10

two spermatids - 23 chromosomes each

Question 11

Each primary spermatocytes produces how many spermatids?

Answer 11

4

Question 12

What is spermatogenic transmortion?

Answer 12

spermatids bud out to form spermatozoa

Question 13

What structure of the spermatozoa helps them digest the lining of the egg?

Answer 13

acrosome

Question 14

What is the function of Leydig cells?

Answer 14

They convert cholesterol to testosterone

Question 15

What does testosterone do in Sertoli cells?

Answer 15

It binds a receptor, converting into dihydrotestosterone, which diffuses into the nucleus and instructs DNA to synthesize RNA.

Question 16

What does LH do in the testes?

Answer 16

It binds to Leydig cell receptors resulting in a second messenger that increasing the conversion of cholesterol to testosterone.

Question 17

What does FSH do in the testes?

Answer 17

It binds to Sertoli cell receptors, resulting in a secondary response that converts testosterone to hydrotestosterone.

Question 18

What feedback mechanism results if testosterone is too high?

Answer 18

It inhibits the hypothalamus’ release of GnRH and anterior pituitary’s release of LH.

Question 19

What feedback mechanism results when dihydrotestosterone is too high?

Answer 19

It inhibits the anterior pituitary’s release of FSH.

Question 20

What hormone is responsible for secondary sex characteristics in the male?

Answer 20

testosterone

Question 21

Where is sperm stored?

Answer 21

in the epididymis and vas deferens

Question 22

Define oogenesis

Answer 22

production of ova

Question 23

In oogenesis, what occurs during the 2-3 months of female fetal development?

Answer 23

Oogonia undergo mitotic division to produce primary oocytes.

Question 24

Define atresia

Answer 24

the degeneration of immature primary oocytes

Question 25

What happens to primary oocytes during monthly cycles?

Answer 25

There is s surge in LH, causing the first meiotic division that produces a secondary oocyte (23 chromosomes) and first polar body.

Question 26

What happens to the secondary oocyte after fertilization?

Answer 26

It undergoes the second meiotic division to form an ovum (23 chromosomes +23) and a second polar body.

Question 27

What happens in the follicular phase?

Answer 27

The primary oocyte develops into the secondary oocyte and an LH surge causes ovulation.

Question 28

What happens in the luteal phase?

Answer 28

The leftover follicle becomes the corpus luteum, an endocrine gland, producing estrogen and progesterone. It will degenerate if fertilization does not occur and menstruation will result.

Question 29

What causes the LH surge before ovulation?

Answer 29

an increase in estrogen

Question 30

What hormone surges after ovulation?

Answer 30

progesterone

Question 31

What happens in the theca cells?

Answer 31

LH promotes cholesterol conversion to testosterone.

Question 32

What happens in follicle cells during the follicular phase?

Answer 32

Testosterone diffuses in, converting to estrogen, which helps develop the primary oocyte and grow the follicle cell.

Question 33

What feedback mechanism results from low estrogen?

Answer 33

It inhibits FSH.

Question 34

What feedback mechanism results from high estrogen?

Answer 34

It has positive feedback on LH production.

Question 35

What feedback mechanism results from the combination of progesterone and estrogen?

Answer 35

They inhibit FSH, LH, and GnRH.

Question 36

What form is the zygote when it attaches to the uterine lining?

Answer 36

blastocyst

Question 37

What hormone is responsible for the secondary sex characteristics in the female?

Answer 37

estrogen

Question 38

In the first 3 months of pregnancy, what hormones does the placenta synthesize and what are their roles?

Answer 38

- chorionic gonadotropin (CG) stimulates corpus luteum to make estrogen and progesterone - chorionic somatomammotropin (CS) help mammory glands grow

Question 39

In the last 6 months of pregnancy, what makes estrogen and progesterone?

Answer 39

the placenta

Question 40

In the last 6 months of pregnancy, what hormone is no longer made?

Answer 40

chorionic gonadotropin (CG)

Question 41

What are the individual cells called in blastula formation?

Answer 41

blastomeres

Question 42

In a mature vertebrate, what are the parts of the coelom?

Answer 42

thoracic cavity and abdominal cavity

Question 43

What is the blastocoel?

Answer 43

the fluid-filled cavity inside the blastula

Question 44

What three layers form during gastrulation?

Answer 44

endoderm, ectoderm, and mesoderm

Question 45

What is the ectoderm's final differentiation?

Answer 45

skin, nervous tissue

Question 46

What is the mesoderm's final differentiation?

Answer 46

connective tissues, bones, muscle, blood

Question 47

What is the endoderm's final differentiation?

Answer 47

inner lining of digestive/respiratory tracts, major glands like liver and pancreas

Question 48

What is formed during neurulation?

Answer 48

The ectoderm forms a neural tube which will become the nervous system.

Question 49

What do neural crest cells form?

Answer 49

sense organs in the head, sensory cells, adrenal medulla

Question 50

What is direct vs. indirect development?

Answer 50

Direct development involves care being given to the post-embryonic organism, while indirect development is when the organism is left on its own.

Question 51

What is meant by a prepattern of development?

Answer 51

If an egg is separated at the right place (includes grey crescent), it will still form a complete embryo (2)

Question 52

What is meant by developmental induction?

Answer 52

Certain tissues can direct the differentiation of neighboring cells to take on a fate they were not normally designed to fulfill.

Question 53

What specifically forms the barrier between maternal and fetal blood, but allows diffusion?

Answer 53

chorion

Question 54

In mammals, the formation of what structure marks the beginning of gastrulation?

Answer 54

primitive streak

Question 55

What is meant by uterine quiescence?

Answer 55

whether or not it is receptive to embryo implantation

Question 56

When does the uterus being to contract?

Answer 56

When there is a certain ratio of progesterone:estrogen

Question 57

What is the role of oxytocin in parturition?

Answer 57

It induces contractions of uterine smooth muscle and produces prostaglandins which further induce contractions.

Question 58

How is production of milk stimulated?

Answer 58

Suckling causes the hypothalamus to release prolactin releasing hormone (PRH), which causes the anterior pituitary to release prolactin, which causes the mammary glands to produce milk.

Question 59

How is milk ejection stimulated?

Answer 59

Suckling causes oxytocin release from the posterior pituitary, which causes contraction of the myoepithelial cells of the breast.