Reproduction

Question 1

What is mitosis?

Answer 1

Germ cell proliferation.

Question 2

Which type of cell division is mitosis? Which type of cell division is meiosis?

Haploid/diploid?

Answer 2

Mitosis = Diploid

Meiosis = Haploid

Question 3

When does mitosis and meiosis occur in females and males sex cells, respectively?

Answer 3

In females, mitosis occurs in the fetus, whereas meiosis occurs in the reproductive adult.

In males, mitosis AND meiosis occur in the reproductive adult.

Question 4

In females, when is Meiosis I under arrest?

Answer 4

Primary oocyte arrested in fetus until selected for ovulation.

Question 5

In females, when is Meiosis II under arrest?

Answer 5

Secondary oocyte arrested in reproductive adult unless fertilized.

Question 6

What happens if an egg is unfertilized?

Answer 6

It degenerates.

Question 7

How many eggs does 1 primary oocyte yield?

Answer 7

1 egg.

Question 8

How many sperm does 1 primary spermatocyte yield?

Answer 8

4 sperm.

Question 9

What happens to polar bodies? At what points are they created?

Answer 9

They disintegrate.

First polar body created during Meiosis I. Second polar body created during Meiosis II.

Question 10

What is the main hormone product of testes?

Answer 10

Testosterone (an androgen).

Question 11

What is the main hormone product of ovaries?

Answer 11

Estradiol (an estrogen) and progesterone (a progestin).

Question 12

What do all gonadal steroids mediate?

Answer 12

Feedback at hypothalamus and anterior pituitary, with the exception of estradiol.

Question 13

What will sustained high levels of estradiol cause?

Answer 13

Massive surge release of LH/FSH.

Positive feedback.

Question 14

Which androgen-dependent feature occurs in some species of male mammals?

Answer 14

Testicular migration into scrotal sac.

Question 15

What is cryptochidism?

Answer 15

The failure of testicles to descent.

Question 16

What temperature is required for normal spermatogenesis?

Answer 16

2-3 degrees less than body temperature.

Question 17

What is the epididymis?

Answer 17

A highly convoluted duct behind the testis, along which sperm passes to the vas deferens.

Question 18

What is a spermatid?

Answer 18

It has completed meiosis, but not yet undergone cell remodeling to become final sperm.

Question 19

How is the “blood-testes barrier” formed?

Answer 19

A formation between he basal lamina, cells associated with basal lamina, and tight juctions between Sertoli cells.

Question 20

What are the effects of testicular androgens?

Answer 20

• Negative feedback control of LH/FSH and GnRH.
• Primary sex characteristics
• Secondary sex characteristics
• Behaviour

Question 21

What are the primary sex characteristics for males?

Answer 21

• Development and maintenance of internal and external genitalia.
• Support of spermatogenesis.

Question 22

What is testosterone often converted into, once in the target tissues?

Answer 22

DHT.

Question 23

What is DHT required for?

Answer 23

• Differentiation of external genitalia during development.
• Development and support of accessory sex glands.
• Male pattern baldness, acne, facial hair.

Question 24

What is the endometrium?

Answer 24

The inner lining of the uterus.

Question 25

What is the myometrium?

Answer 25

Smooth muscle of uterus.

Question 26

What are the layers of a tertiary follicle (from outermost to innermost)?

Answer 26

- Theca - Basal lamina - Granulosa cells - Antrum

Question 27

Describe the levels of FSH and LH during the follicular phase, ovulation, and the luteal phase.

Answer 27

During the follicular phase, FSH and LH levels are both low. FSH and LH levels rise dramatically in preparation for ovulation, and right after ovulation, immediately drop off. Higher levels of LH than FSH. During the luteal phase, levels of FSH and LH return to baseline.

Question 28

What is considered the beginning of the follicular phase?

Answer 28

Begins with the luteal regression -> Low ovarian steroids -> Menses.

Question 29

What happens to the ovary during the follicular phase?

Answer 29

- Selected follicle begins to grow and secrete estrogen. - Sustained exposure to high estrogen/low progesterone causes massive release of gonadotropins. - LH surge leads to ovulation.

Question 30

What happens to the uterus during the follicular phase?

Answer 30

- Part of the endometrial lining shed due to steroid withdrawal, leading to menses. - Rising estrogen (from maturing follicle) stimulates regrowth of lining (proliferative phase).

Question 31

What is considered the beginning of the luteal phase?

Answer 31

Begins with LH surge, which triggers ovulation.

Question 32

What happens to the ovary during the luteal phase?

Answer 32

- Oocyte escapes ovary, completes meiosis I in response to LH surge, then arrests again in meiosis II. - Somatic cells of ovulatory follicle transform into luteal cells, which form solid, progesterone-secreting structure (luteinization). - High ovarian steroids suppress gonadotropins, preventing growth of large follicles. - In the absence of pregnancy, luteal regression.

Question 33

What happens to the uterus during the luteal phase?

Answer 33

- Under influence of progesterone and estrogen, continues to prepare for pregnancy (secretory phase). - Luteal regression -> steroid withdrawal -> menses.

Question 34

What is parturition?

Answer 34

- Cervical softening/ripening - Initiation of rhythmic uterine contractions - Delivery of the baby - Expulsion of the placenta

Question 35

What is parturition controlled by?

Answer 35

Sequential cascade of hormones.

Question 36

What is the role that oxytocin plays with parturition?

Answer 36

Positive feedback/neuroendocrine reflex.

Question 37

What is the process of labour and positive feedback?

Answer 37

1) Cervical stretch 2) Oxytocin release 3) Uterine contractions 4) Push baby against cervix 5) Causes more cervical stretch 6) Delivery of baby ends cycle