Gonads

Question 1

What are the female Gonads and their Hormones?

Answer 1

Ovaries

• Estrogens (predominantly estradiol) – steroid hormones
• High concentration of aromatase – catalyzes conversion of androgens to estrogen

estradiol = estrogen

Question 2

What are the male Gonads and their Hormones?

Answer 2

Testes

• Androgens (primarily testosterone) – steroid hormones
• High concentration of enzymes that convert androstenedione to testosterone

Question 3

Are testosterone and estrogen exclusive to males or females?

Answer 3

Testosterone and estrogen are not unique to males and females, however, the ratio between the two differs

both derived from cholesterol, in presence of aromatase, androstenedione becomes estrogen. Without aromatase, androstenedione becomes testosterone
(higher level of aromatase in the ovaries)

Question 4

What are the functions of the Male Gonads and Sex Hormones?

Answer 4

Testes: produce testosterone (steroid hormone) and sperm (gametogenesis – spermatogenesis)

Question 5

Where does Spermatogenesis take place?

Answer 5

Spermatogenesis in the seminiferous tubules

Question 6

Where is Testosterone secreted from?

Answer 6

Testosterone secreted from Leydig cells
(found around the seminiferous tubules)

Question 7

What are the 2 primary Androgens?

Answer 7

1. Testosterone

• Majority is synthesized in the testes

2. Dehydroepiandrosterone (DHEA) and androstenedione

• Synthesized in the adrenal cortex
• Much less potent than testosterone

Question 8

What are the effects of testosterone in males?

Answer 8

Question 9

How does testosterone convert?

Answer 9

Testosterone Transformation in Target Tissues

Adult prostate and tissues with 5-⍺-reductase: conversion to
dihydrotestosterone (DHT) (a more potent version of testosterone)

Brain: conversion to estradiol by aromatase

chatgpt

Question 10

make into cards

Answer 10

Hypothalamus secretes GnRH
acts on anterior pituatiry to release FSH and LH
FSH and LH enter testes and act on Sertoli Cells and Leydig Cells
Sertoli cells is responsible for paracrine factors in spermatogenesis

inhbin stops FSH secretion -> negative feedback loop
testosterone stops LH secretion and GnRH secretion - Negative fb loop

Question 11

What is the purpose of Anabolic Steroid Use?

Answer 11

• Use of synthetic androgens to improve increase muscle hypertrophy, sport performance etc.
• Negative effects include but are not limited to overstimulation of the prostate gland, aggression and development of breast tissue

Question 12

Why is taking testosterone bad?

Answer 12

two symptoms ->
when exogeneous testosterone is increased, endogenous testosterone decreases, resulting in reduced testicular size and sperm count

Question 13

What is the function of Gonads and Sex Hormones in the Females?

Answer 13

Ovaries: produce ova (gametogenesis), estrogen and progesterone (steroid hormones)

• Maturation of female gamete (ovum) is cyclical (unlike male gamete which is continuous)
• Average menstrual cycle is 28 days

ova = egg

Question 14

Differentiate b/w the 3 hormones of estrogen

Answer 14

Question 15

Maturation of Ova

What are Oocytes?

Answer 15

Oocytes, also known as ova or egg cells, are the female reproductive cells produced by the ovaries. They are the largest cells in the human body and are essential for sexual reproduction in females.

surrounded by granulosa cells

Question 16

What are Granulosa Cells?

Answer 16

secrete estrogen, and just before ovulation, small amounts of progesterone and inhibin

They surround and support the developing oocyte (egg cell) within the follicle and play essential roles in follicle development, ovulation, and hormone production.

Question 17

What is Theca?

Answer 17

granulosa cells that have proliferated and differentiated during follicle maturation. Also produces estrogen

Question 18

What are Preantral and early antral follicles?

Answer 18

Preantral and early antral follicles are always present in the ovaries between puberty and menopause (they require FSH to further develop)

• At the start of menstrual cycle 10-25 of these already present preantral and early antral follicles begin to develop into larger follicles

one becomes dominant nad the rest of them die,
only one fully matures

Question 19

What is atresia?

Answer 19

• ~1 week into the cycle, a dominant follicle continues to develop, and the others undergo atresia (cell death)
• Just before ovulation, the dominant follicle becomes so large that it balloons on the surface of the ovary

Question 20

When does ovulation occur?
What is the corpus luteum?

Answer 20

Ovulation occurs when the walls of the follicle and ovary rupture (due to enzymatic digestion) and the oocyte is carried out

Once the follicle discharges the oocyte, the granulosa cells enlarge to become the corpus luteum which secretes large amounts of estrogen, progesterone and inhibin

Question 21

Follicular Phase

Answer 21

Day 1 -14
Estrogen from granulosa cells of follicle
Progosterone synthesized and screted in very samll amounts by theca and granulosa (just before ovulation)

Question 22

Luteal Phase

Answer 22

Day 14 - 28
Corpus Luteum primarily secrete and sythesize estrogen and progesterone

Question 23

Order of Events

Answer 23

Question 24

What hypophysiotropic hormone stimulates the anterior pituatiry to release FSH and LH? What glands do they act on? What actions do they cause?

Answer 24

GnRH stimulates anterior pituitary
FSH and LH act on testes and ovaries
Releases Testosterone and Estrogen/Progesterone
Testosterone -> Spermatogeneis
Estrogen/Progosterone -> stimulates changes in Ovaries