Endocrinology - Male Reproductive System
1. What are the male reproductive functions?: - Spermatogenesis: formation of sperm
- performance of the male sexual act
- regulation of male reproductive functions by the various hormones
2. What are the 3 male sex hormones?: - testosterone
- dihydrotestosterone (DHT)
- androstenedione
3. What is the primary testicular hormone?: - Testosterone
4. What is the difference between testosterone and DHT?: - DHT is 10 times more potent
and testosterone is converted to DHT in target tissue for greater biological activity
5. What are steroids synthesized from?: - cholesterol or acetyl coenzyme A
6. How is estradiol/estrogen produced in males?: - Sertoli cells in the seminiferous tubules
convert Testosterone to Estradiol and this high local estrogen concentration plays a role in spermiogenesis (maturation
of sperm)
- the liver converts testosterone to estrogen and accounts for 80% of male estrogen production
,7. What stage of development do male external genitalia develop in and what
occurs?: Fetal stage
- formation of penis and scrotum instead of clitoris and vagina
8. What stage of development do internal male reproductive structures develop
in and what occurs?: Fetal stage
- formation of the prostate gland, seminal vesicles, and male genital ducts
- suppression of female genital organ development
9. What occurs in the neonatal stage due to testosterone?: - testosterone promotes the
descent of the testes into the scrotum, as the sperm must be in an area with colder temperature
10. What occurs during puberty and adulthood in men due to testosterone?: -
increases sperm production
- supports the development of secondary sexual characteristics
11. What is the function of testosterone in puberty and adulthood in men?: In-
creases
- skin thickness and contributes to acne development
,- protein synthesis and muscle growth
- bone matrix formation and calcium retention
- basal metabolic rate (BMR)
, - red blood cell production
Enlarges
- penis, scrotum, and testes
- larynx and laryngeal mucosa (deepening of voice)
Promotes
- libido
- hair growth over the pubis, line alba, face, chest, and back
Decreases
- hair growth on the scalp
- fat mass
12. DHT and testosterone relationship to hair:
13. What is testosterone secreted by and how does it affect spermatogenesis?: -
secreted by Leydig cells in the testicular interstitium
- essential for the initiation and maintenance of spermatogenesis
14. What is LH secreted by and how does it affect spermatogenesis?: - secreted by
anterior pituitary gland
- stimulates Leydig cells to produce testosterone
1. What are the male reproductive functions?: - Spermatogenesis: formation of sperm
- performance of the male sexual act
- regulation of male reproductive functions by the various hormones
2. What are the 3 male sex hormones?: - testosterone
- dihydrotestosterone (DHT)
- androstenedione
3. What is the primary testicular hormone?: - Testosterone
4. What is the difference between testosterone and DHT?: - DHT is 10 times more potent
and testosterone is converted to DHT in target tissue for greater biological activity
5. What are steroids synthesized from?: - cholesterol or acetyl coenzyme A
6. How is estradiol/estrogen produced in males?: - Sertoli cells in the seminiferous tubules
convert Testosterone to Estradiol and this high local estrogen concentration plays a role in spermiogenesis (maturation
of sperm)
- the liver converts testosterone to estrogen and accounts for 80% of male estrogen production
,7. What stage of development do male external genitalia develop in and what
occurs?: Fetal stage
- formation of penis and scrotum instead of clitoris and vagina
8. What stage of development do internal male reproductive structures develop
in and what occurs?: Fetal stage
- formation of the prostate gland, seminal vesicles, and male genital ducts
- suppression of female genital organ development
9. What occurs in the neonatal stage due to testosterone?: - testosterone promotes the
descent of the testes into the scrotum, as the sperm must be in an area with colder temperature
10. What occurs during puberty and adulthood in men due to testosterone?: -
increases sperm production
- supports the development of secondary sexual characteristics
11. What is the function of testosterone in puberty and adulthood in men?: In-
creases
- skin thickness and contributes to acne development
,- protein synthesis and muscle growth
- bone matrix formation and calcium retention
- basal metabolic rate (BMR)
, - red blood cell production
Enlarges
- penis, scrotum, and testes
- larynx and laryngeal mucosa (deepening of voice)
Promotes
- libido
- hair growth over the pubis, line alba, face, chest, and back
Decreases
- hair growth on the scalp
- fat mass
12. DHT and testosterone relationship to hair:
13. What is testosterone secreted by and how does it affect spermatogenesis?: -
secreted by Leydig cells in the testicular interstitium
- essential for the initiation and maintenance of spermatogenesis
14. What is LH secreted by and how does it affect spermatogenesis?: - secreted by
anterior pituitary gland
- stimulates Leydig cells to produce testosterone
