14.3 Hormonal Regulation Flashcards
When is Chromosomal Sex determined?
At fertilization
Which chromosome is male?
XY
Which chromosome is female?
XX
At what week in development do male and females begin to differ?
The 7th week
What gene does the why chromosome carry?
The Testis-Determining Factor
What does the Testis-determining factor do?
It triggers the production of male sex hormones
What are Androgens?
Another name for male sex hormones
What does the presence of androgens do?
Initiates development of the male sex organs in the fetus
What is Puberty?
The period in which the reproductive system completes its development and becomes fully functional
What physical changes does puberty lead to?
Development of the sex organs as well as development of the secondary sex characteristics
How does puberty begin?
The hypothalamus increases its production of Gonadotropin releasing hormone (GnRH)?
What does The Gonadotropin releasing hormone do?
It acts on the anterior pituitary gland causing it to release Follicle stimulating hormone (FSH) and Luteinizing hormone (LH)
What does the Follicle stimulating hormone (FSH) and Luteinizing hormone (LH) do in males?
They cause testes to begin producing sperm and to release testosterone
What controls the the production of sperm?
Negative feedback
How does negative feedback control sperm?
FSH and LH causes the interstitial cells to produce sperm. At the same time FSH causes some cells to release inhibin. The inhibin. Inhibin acts on the anterior pituitary to inhibit the production of FSH. As the FSH levels drop, the testes release less inhibin. A release in the level of inhibin causes the anterior pituitary to release more FSH
How does the negative feedback loop regulate secondary sex characteristics?
LH causes the testes to produce testosterone. Testosterone acts on the anterior pituitary to inhibit the release of LH
Why do steroids inhibit sperm production?
Because they interrupt hormone feedback systems by mimicking the effects of testosterone. So they increase the amount of inhibin releases which stops the production of FSH
What are the side effects of steroids?
Shrinking testicles
Low sperm count
Loss of body hair
Development of breasts
What is Andropause?
The decline of the testosterone level in men
What are the symptoms of Andropause?
Fatigue, depression, loss of muscle and bone mass, and a drop in sperm production
How is the prostate gland affected with age?
The prostate gland grows with age
What can a grown prostate gland lead to?
Urinary difficulties because the prostate squeezes on the urethra as it grows
What is Prostatitis?
The inflammation of the prostate that causes a burning sensation when urinating and the need to urinate more frequently. Treated with antibiotics
What begins puberty in a female?
The release of Gonadotropin Releasing Hormone GnRH
What does the Gonadotropin releasing hormone do?
They trigger the release of LH and FSH from the anterior pituitary
How does FSH and LH act on the ovaries?
It causes them to produce the female sex hormones estrogen and progesterone
What do estrogen and progesterone do in puberty?
Stimulate the development of female secondary sex characteristics and launch a reproductive cycle
What does the menstrual cycle ensure?
That an ovum is released at the same time as the uterus is most receptive to a fertilized egg
How long is the menstrual cycle and how does it start?
The menstrual cycle is 28 days long and starts with menstruation
what are the 2 cycles of the menstrual cycle?
The ovarian cycle and the uterine cycle
What does the ovary contain?
Cellular structures called follicles
How many follicles are left when puberty begins?
400,000
What happens to a follicle after it matures and releases an ovum?
It develops into a yellowish gland called a corpus luteum
What are the two stages in the ovarian cycle?
Follicular stage and the luteal stage
How does the follicular stage begin?
With an increase in the level of FSH released by the anterior pituitary
How does FSH affect a follicle in the follicular stage?
It stimulates it to mature and release progesterone and estrogen
What inhibits the production of FSH in the follicular stage?
The rising level of estrogen in the blood acts on the anterior pituitary to inhibit the release of FSH
What does estrogen released by a maturing follicle do in the follicular stage?
Inhibits the release of FSH and also triggers a sudden release of GnRH
What does a the sudden release of GnRH caused by a maturing follicle do?
Increases the production of LH which triggers ovulation (when the follicle bursts and the egg is released)
What begins the Luteal stage of the Ovarian cycle?
Ovulation
What happens to the follicle once the ovum is released?
LH causes the follicle to develop into corpus luteam
What does the Corpus Luteum do?
Secretes progesterone and some estrogen
What inhibits the release of FSH and LH in the luteal stage of the ovarian cycle?
The increase of estrogen and progesterone in the blood released by the Corpus Luteum
What happens as the corpus luteum degenerate?
There is an decrease in the levels of progesterone which causes the anterior pituitary to release FSH and LH again and the cycle repeats
What happens if the ovum is fertilized and implanted in the endometrium?
Blood hormone levels of progesterone and estrogen remain under stimulus of HCG released by embryo supporting membranes
What does progesterone do if an embryo is implanted?
Maintains support of the endometrium to support a developing fetus
What does estrogen do if an embryo is implanted?
Stops the ovarian cycle so no additional follicles mature
On what day does ovulation take place?
Day 14
What do the events of the uterine cycle cause?
A build-up of blood vessels and tissues in the endometrium
What happens if fertilization does not occur?
The endometrium disintegrates and fertilization occurs
What day does the uterine cycle begin?
On the first day menstruation, which is also the first day of the ovarian cycle
What happens in reference to the corpus luteum on the first day of menstruation?
It has degenerated and the levels of sex hormones in the blood are low
What happens to the hormones as a new follicle begins to mature in the uterine cycle?
The level of estrogen in the blood gradually increases
What happens on the sixth day of the uterine cycle?
The estrogen level is high enough to cause the endometrium to begin thickening
How does the release of progesterone released by the corpus luteum affect the body?
It causes the endometrium to begin thickening rapidly
What happens between days 15 and 23 of the uterine cycle?
The thickness of the endometrium may even double or triple
What happens if fertilization does not occur in the uterine cycle?
The corpus luteum degenerates and the levels of sex hormones drop and the endometrium breaks down and menstruation begins
What causes menopause?
The decrease in follicles in the ovaries that stop releasing progesterone and estrogen
What can menopause overtime lead to?
Rising cholesterol levels, diminishing bone mass, and increased risk of uterine cancer, breast cancer, and heart disease
