Reproduction: The Reproductive System (HY)

Question 1

What are mutations in the X chromosome called?

Answer 1

X-linked or sex linked

Question 2

Why do females express X-linked disorders much less frequently than males?

Answer 2

Males are hemizygous for many genes on the X chromosome (only have one copy of the gene), but females are homozygous or heterozygous.
Most X-linked disorders are recessive, so one mutation in females wouldn’t express but one mutation in males would express.

Question 3

What is the sex-determining region Y (SRY) on the Y chromosome?

Answer 3

Y chromosome gene that codes for a transcription factor that leads to testis differentiation and male gonad formation.
without this region, all zygotes will be female.

Question 4

What is the pathway for sperm?

Answer 4

SEVE(N) UP

1. seminiferous tubules (development)
2. epididymis (motility and storage)
3. vas deferens
4. ejaculatory duct
5. urethra
6. penis

Question 5

What cells in the testes release androgens (male sex hormones)?

Answer 5

Interstitial cells of Leydig

Question 6

What cells in the testes nourish sperm cells?

Answer 6

Sertoli cells

Question 7

Where are the testes located?

Answer 7

scrotum

Question 8

What produces seminal fluid?

seminal fluid + sperm = semen

Answer 8

seminal vesicles, prostate gland, and bulbourethral (Cowper’s) gland

Question 9

What compound do seminal vesicles add to seminal fluid?

Answer 9

fructose to nourish sperm

Question 10

what do seminal vesicles and prostate gland do to pH of seminal vesicles?

Answer 10

make it mildly basic so that sperm will survive in mildly acidic female reproductive tract

Question 11

What does the bulbourethral (Cowper’s) gland do?

Answer 11

produce clear viscous liquid that cleans and lubricates urethra

Question 12

what is spermatogenesis?

Answer 12

formation of haploid sperm through meiosis

Question 13

starting from diploid stem cells to mature sperm, what are the stages of sperm?

Answer 13

spermatogonia (diploid stem cell) –> primary spermatocytes (after S stage) –> secondary spermatocytes (after meiosis I) –> spermatids (after meiosis II) –> spermatozoa (maturation)

Question 14

What are the three structural parts of sperm, and what is each’s function?

Answer 14

head - genetic material, penetrates ovum with enzymes in acrosome
midpiece - ATP from fructose
flagellum - motility

Question 15

what is the pathway for female eggs?

Answer 15

follicles in ovaries –> peritoneal sac –> fallopian tube (oviduct) –> uterus (fetal development)

Question 16

where is sperm deposited in the female reproductive tract?

Answer 16

vaginal canal, which is connected to the cervix, which is at the bottom of the uterus

Question 17

what is ovulation?

Answer 17

when one egg per month leaves the ovaries towards the rest of the reproductive tract
occurs between puberty and menopause

Question 18

What is oogenesis?

Answer 18

formation of female gametes

Question 19

what is menarche?

Answer 19

first menstrual cycle

Question 20

How are the meiotic processes of oogenesis different from spermatogenesis (hint: 4)? At what two points does oogenesis pause?

Answer 20

1. all oogenia are made during fetal development; no unending supply of stem cells for females
2. by birth, all oogenia have undergone S stage, so they all become primary oocytes (paused at prophase I)
3. Every menstrual cycle, meiosis I produces secondary oocytes and polar body through unequal cytokinesis (paused at metaphase II)
4. upon fertilization, meiosis II completes to produce one large mature ovum, and haploid pronuclei of ovum and sperm join to create diploid zygote

Question 21

what are the two structures of oocytes?

Answer 21

1. zona pellucida: surrounds and protects oocyte, cell binding
2. corona radiata: outside the zona pellucida; cells that adhered to oocyte during ovulation

Question 22

what is the name for external female anatomy?

Answer 22

vulva

Question 23

At the start of puberty, what hormonal pathway occurs and what glands are involved to trigger the production of sex hormones?

Answer 23

hypothalamus produces ganodotropin-releasing homrone (GnRH) –> triggers anterior pituitary gland to produce FSH (follicle stimulating hormone) and LH (luteinizing hormone)

Question 24

What two cells do FSH and LH, and what is the result?

Answer 24

FSH stimulates Sertoli cells to nourish sperm, triggering sperm maturation
LH causes interstitial cells to produce testosterone

Question 25

What hormone is secreted in response to FSH in females? What are the roles of this hormone in embryo and adults?

Answer 25

estrogen 1. in embryo, development of female reproductive tract 2. in adults, thickening of uterus lining (endometrium)

Question 26

what hormone is secreted in response to LH, and what secretes this hormone? what is the role of progesterone?

Answer 26

1. progesterone is secreted by corpus luteum | 2. progesterone is involved in development and maintenance of endometrium

Question 27

what is the menstrual cycle, and what are it's four stages

Answer 27

the growing and shedding of the endometrial lining in response to rising and falling estrogen/progesterone levels 1. follicular phase 2. ovulation 3. luteal phase 4. menstruation

Question 28

what occurs during the follicular phase of menstrual cycle?

Answer 28

1. GnRH secretion leads to FSH and LH secretion --> follicle development 2. follicles produce estrogen --> vascularization and glandularization of decidua (decidua is a modified versino of endometrium)

Question 29

what occurs during ovulation phase of menstrual cycle?

Answer 29

1. surge of LH, FSH, and GnRH secretion because past a certain threshold of estrogen concentration it stops negative feedback and starts positive feedback 2. surge of LH induces ovulation, released of ovum from ovary into peritoneal sac in abdominal cavity

Question 30

what occurs during the luteal phase of the menstrual cycle?

Answer 30

1. LH causes ruptured follicle to become corpus luteum that secretes progesterone to maintain uterine lining 2. high estrogen and progestrone negative feeback on GnRH, LH, and FSH --> prevent ovulation of multiple eggs

Question 31

what occurs during mentruation phase of mentrual cycle?

Answer 31

only occurs if there is no fertilization 1. low LH level --> progesterone levels decline --> uterine lining sheds 2. low estrogen and progesterone --> block on GnRH production is removed, stimulating next cycle

Question 32

what occurs if fertilization does occur?

Answer 32

1. blastula produces human chorionic gonadotropic (hCG), an LH analog that maintains corpus luteum 2. high estrogen and progesterone --> inhibit further GnRH secretion

Question 33

what supplies progesterone and estrogen during later in pregnancy?

Answer 33

placenta

Question 34

what occurs during menopause?

Answer 34

ovaries become less sensitive to FSH and LH --> less estrogen and progesterone --> endometrium atrophies --> menstruation stops lower estrogen and progesterone --> higher blood levels of FSH and LH