Human Reproductive System - 14.3

Question 1

When is the chromosomal sex or genetic sex determined?

Answer 1

At fertilization

Question 2

What is the sex chromosome combination for a male?

Answer 2

XY

Question 3

What is the sex chromosome combination for a female?

Answer 3

XX

Question 4

How long are male and female embryos anatomically identical?

Answer 4

Until about 7th week of development

Question 5

When does the development of male sex organs begin?

Answer 5

Before birth

Question 6

What does the Y chromosome carry in males?

Answer 6

Testis determining factor gene (TDF)

Question 7

What does TDF do?

Answer 7

Triggers the production of male sex hormones

Question 8

What is another word for male sex hormones?

Answer 8

Androgens

Question 9

What does the presence of Androgens cause?

Answer 9

Initiates the development of male sex organs and ducts in the fetus

Question 10

What is puberty?

Answer 10

Period in which the RS completes its development and becomes fully functional

Question 11

When do most boys enter puberty?

Answer 11

Between ages 10 and 13 years old

Question 12

What are the changes that puberty causes?

Answer 12

*Final development of the sex organs

• Final development of the secondary characteristics

Question 13

What does GnRH cause the anterior pituitary to secrete?

Answer 13

*FSH
*LH

Question 14

What do FSH and LH cause in males?

Answer 14

Cause the testes to begin producing sperm and to release testosterone

Question 15

What does FSH cause in males?

Answer 15

• Causes the interstitial cells in the testes to produce sperm
• Causes the cells in the seminiferous tubules to produce inhibin

Question 16

What does inhibin do?

Answer 16

Acts on the anterior pituitary to inhibit the production of FSH (negative feedback loop)

Question 17

What happens when FSH levels drop?

Answer 17

Testes release less inhibin
Decrease in inhibin causes the anterior pituitary to secrete more FSH

Question 18

What does LH cause in males?

Answer 18

Causes the testes to release testosterones - promotes changes in muscle development and the formation of facial hair

Question 19

What happens when there are high levels of testoserone in the body?

Answer 19

Acts on the anterior pituitary to inhibit the release of LH

Question 20

What are side affects of antibiotic steroids?

Answer 20

Shrinking testicles, low sperm county, loss of body hair, growth of breasts

Question 21

What is andropause?

Answer 21

When testosterone levels decline in males (around age 40)

Question 22

What are symptoms of andropause?

Answer 22

Fatigue, depression, loss of muscle/bone mass. drop in sperm production

Question 23

When does puberty happen in girls?

Answer 23

Between ages 9 to 13 years old

Question 24

What do FSH and LH cause in the female RS?

Answer 24

Act on the ovaries to produce the female sex hormone: estrogen and progesterone

Question 25

What is the pattern in the female reproductive system called?

Answer 25

The menstrual cycle

Question 26

What does the menstrual cycle ensure?

Answer 26

It ensures that the ovum is released at the same time that the uterus is most receptive to a fertilized egg

Question 27

How long does the menstrual cycle last?

Answer 27

About 28 days - cycle ends with menstruation and ends with the starts of the next menstruation period

Question 28

What cycle of the menstrual cycle takes place in the ovaries?

Answer 28

Ovarian cycle

Question 29

What cycle of the menstrual cycle takes place in the uterus?

Answer 29

The uterine cycle

Question 30

What controls the the ovarian and uterine cycle?

Answer 30

estrogen and progesterone

Question 31

What happens when a follicle matures and releases an ovum?

Answer 31

It develops into the corpus luteum

Question 32

What is the first stage of the ovarian cycle?

Answer 32

The follicular stage

Question 33

What is the second stage of the ovarian cycle?

Answer 33

The luteal stage

Question 34

What happens in the follicular stage?

Answer 34

* FSH stimulates follicle to mature * As follicle develops it secretes progesterone and estrogen *Rising levels of estrogen in blood acts on the anterior pituitary to to inhibit the release of FSH *Estrogen triggers hypothalamus to secrete GrNH *anterior pituitary secretes Lh which triggers ovulation - follicle bursts releasing ovum

Question 35

What happens in the luteal stage?

Answer 35

*LH causes the follicle to develop into a corpus luteum * Corpus luteum secretes sone progesterone and some estrogen * As corpus luteum degenerates there are low levels of sex hormones - anterior pituitary secretes hormones again - cycle starts again

Question 36

What happens to levels of estrogen and progesterone if ovum is fertilized?

Answer 36

They remain high under stimulus of hCG - released by embryo supporting membranes

Question 37

What does the continued presence of estrogen and progesterone do?

Answer 37

*Progesterone - maintains the endometrium to support developing follicles * Estrogen - stops the ovarian cycle so no additional follicles mature

Question 38

What day does ovulation take place?

Answer 38

Day 14 - halfway through the ovarian cycle

Question 39

How long does the ovum survive after ovulation?

Answer 39

24 hours

Question 40

What does the uterine cycle ensure?

Answer 40

That the uterus is prepared to receive and nurture a new life.

Question 41

Does the uterine cycle begin on the first day of mensturation?

Answer 41

Yes - this day the luteum has degenerated and the sex hormones in the blood are low

Question 42

What causes a rapid thickening of the endometrium?

Answer 42

The release of progesterone by the corpus luteum

Question 43

What happens if fertilization does not occur?

Answer 43

* Corpus luteum degenerates * Level of sex hormones are low * Endometrium breaks down * Mensuration begins again

Question 44

What is the complete end of the menstural cycle called?

Answer 44

Menopause

Question 45

What is menopause?

Answer 45

When a woman is no longer fertile and is no longer able to produce ova

Question 46

What are symptoms of menopause?

Answer 46

*Blood vessels alternately constrict and dilate * Change in mood * Cholesterol levels rise *Diminishing bone mass * Increased uterine, breast, and heart cancer

Question 47

What can one consider during menopause?

Answer 47

To get hormone replacement therapy (prescription of low levels of estrogen with or without progesterone)

Question 48

What are the risks of hormone replacement theory?

Answer 48

*Increased coronary heart disease, strokes, and blood clots *Increase breast cancer and colorectal cancer *Increased risk of dementia