Male Reproductive System. Prof. K. Sivapalan. Structure • • • • • • • • • Ureter Vase Difference Ampula Seminal Vesicle Prostrate Urethra Epididimis Testes Prepuce Male Reproductive system.
Download ReportTranscript Male Reproductive System. Prof. K. Sivapalan. Structure • • • • • • • • • Ureter Vase Difference Ampula Seminal Vesicle Prostrate Urethra Epididimis Testes Prepuce Male Reproductive system.
Slide 1
Male Reproductive System.
Prof. K. Sivapalan.
Slide 2
Structure
•
•
•
•
•
•
•
•
•
2014
Ureter
Vase Difference
Ampula
Seminal Vesicle
Prostrate
Urethra
Epididimis
Testes
Prepuce
Male Reproductive system
2
Slide 3
Blood Testis Barrior• Tight junctions between adjacent
Sertoli Cells.
• This prevents large molecules
penetrating.
• Steroids can diffusebecause of fat
solubility.
• Fluid in seminiferous tubules is
different from plasma- low glucose and
protein. Rich in androgens, estrogens,
K+, inositol, glutamic acid and aspartic
acid.
2014
Male Reproductive system
3
Slide 4
Spermatogenesis
• Spermatogonia [Primitive
germ dells] begin mitotic
division.
• Primary spermatocytes
undergo meiotic [reduction]
division.
• Secondary spermatocytes
• Early Spermatids
• Late Spermatids- develop tail.
• Spermatozoa.
• The descendants remain tied
to Sertoli cell until the late
spermatid state.
• One spermatogonium – 512
spermatozoa [74 days].
2014
Male Reproductive system
4
Slide 5
Sperm.
• Head- chromosomal
material.
• Acrosome- cap on head,
rich in enzymes for
penetration corona radiata
and ovum.
• Proximal portion of the tail
is wrapped in a membrane
packed with mitochondria.
• Capability of motility
develops as it moves
through epididimis.
• Several inhibitory proteins
in the fluid inhibit motility
until ejaculation.
2014
Male Reproductive system
5
Slide 6
Effects of Temperature- 32°C
• Air circulating around the scrotum.
• Counter current exchange between
spermatic arteries and veins.
• Un-descended testes, testes wrapped
closely with body by tight bindersdegeneration and sterility.
• Hot baths- 43 – 45° for 30 minutes and
insulated supporters reduce sperm count
by 90 %.
2014
Male Reproductive system
6
Slide 7
Effect of Hormones.
• Leutinizing Hormone- stimulate Testosterone
secretion.
• Testosterone is essential for growth and division
of germinal cells.
• Follicular Stimulating Hormone- stimulates
Sertoli cells. Absence- no maturation of sperms.
• Estrogens produced by testis is also essential.
• Growth hormone and other hormones also
necessary.
2014
Male Reproductive system
7
Slide 8
Function of Seminal Vesicles.
• Secrets mucoid material with fructose, citric acid,
other nutrients, prostaglandins and Fibrinogen.
• Seminal vesicles empty their contents during
emission into ejaculatory duct.
• Prostaglandins may– modify cervical mucus for sperm motility and
– reverse peristalsis in uterus and fallopian tubes to
facilitate sperm motility.
• Largest volume contribution to the semen.
2014
Male Reproductive system
8
Slide 9
Function of the Prostate.
• Secrets thin milky fluid with calcium,
citrate, phosphate, a clotting enzyme and
profibrinolysin.
• Empties during emission by contraction of
the capsule and ads to bulk of the semen.
• Alkalinity essential to neutralize the acidity
of the seminal vesicular fluid and vaginal
secretions.
2014
Male Reproductive system
9
Slide 10
Semen.
•
•
•
•
•
•
Sperm and vas deferens fluid- 10 %
Fluid from seminal vesicle- 60 %
Fluid from prostate- 30 %.
The pH is 7.5, 2.5 to 3.5 ml.
Sperm count- 100,000,000 per ml.
Clotted on ejaculation [fibrinogen from seminal
vesicle and clotting enzyme from prostate]
• The coagulum dissolves in 15 to 30 minutes
[prostatic profibrinolysin activated]
• Life of ejaculated sperm is about 48 hours.
[storage in Vas deference 42 days]
2014
Male Reproductive system
10
Slide 11
Abnormalities of Spermatogenesis.
• Infections- bilateral orchitis due to mumps.
• Inborn degenerate tubular epithelia due to
strictures in genital ducts.
• Excessive temperature of the testes due to
failure to descend [cryptorchidism] and hot
environment.
2014
Male Reproductive system
11
Slide 12
Endocrine Function of Testes.
• Secretion of Testosterone-4-9 mg/day
• Transport- 98% in plasma is bound to protein.
• 65% bound β globulin- gonadal steroid binding
globulin.
• 33% bound to albumin.
• Plasma level- 300-1000 ng/dl [10.4-34.7 nmol/L]
in males, 30-70 ng/dl in females.
• Converted to 17-ketosteroiod and excreted in
urine.
2014
Male Reproductive system
12
Slide 13
Secretion of Testosterone and
Spermatogenesis.
2014
Male Reproductive system
13
Slide 14
Actions of Testosterone.
• Feed back control of LH secretion.
• Maintain spermatogenesis along with
FSH.
• Develop and maintain male secondary
sexual characteristics.
• Protein anabolic and growth promoting
effect.
2014
Male Reproductive system
14
Slide 15
Secondary Sexual Characteristics.
• External Genitalia
– Penis increases in length and width.
– Scrotum becomes pigmented and rugose with testicular
enlargement.
• Internal Genitalia.
– Seminal vesicles enlarge and secrete.
– Prostrate and bulbourethral glands enlarge and secrete.
• Voice becomes deeper– Larynx enlarges.
– Vocal cords increase in length and thickness.
• Body conformation– Shoulders broaden, all bones matrix increased.
– Narrow pelvic outlet, [male pelvis]
– Muscles enlarge [50% more than female].
2014
Male Reproductive system
15
Slide 16
Secondary Sexual Characteristics2.
• Hair growth–
–
–
–
Beard appears.
Anterior hair line recedes.
Pubic hair with male pattern [triangle with apex up]
Hair appears in axilla, chest, around anus and
increase in body hair.
– Scalp hair decreases.
• Skin– Sebaceous gland secretion thickens and increases.
– Increased melanin.
• Mental– More aggressive, active attitude.
– Interest in opposite sex.
2014
Male Reproductive system
16
Slide 17
Other Effects.
• Anabolic Effects.
– Growth rate increased by increased synthesis and
reduced breakdown of protein.
– Fusion of epiphysis- ? Estrogen [in males, conversion
of testosterone.]
– Moderate retention of sodium, potassium, calcium,
sulfate, and phosphate.
– Metabolic rate increased.
– Red cell count increased.
• Libido– Increased.
2014
Male Reproductive system
17
Slide 18
Production of Estrogens in Males
• 80 % of estradiol and 95 % of estrone in
plasma is formed by extragonadal
aromatization of circulating testosterone.
• The remainder comes from testes.
• Plasma estradiol- 20-50 pg/dl.
• Production increases with advancing age.
2014
Male Reproductive system
18
Slide 19
Functions of Testosterone During
Fetal Development.
• Testosterone is responsible for the
development of the male sex organs.
• Descent of testes.
2014
Male Reproductive system
19
Slide 20
Regulation of Gonadotropin and
Testosterone Secretion.
• Chorionic gonadotropin stimulates
secretion in fetus.
• GNRH from hypothalamus stimulates LH
and FSH from pituitary.
• Testosterone inhibits LH and Inhibin
inhibits FSH at both levels.
• Psychic factors through limbic system
influence GNRH secretion and sexual
functions- stress can inhibit.
2014
Male Reproductive system
20
Male Reproductive System.
Prof. K. Sivapalan.
Slide 2
Structure
•
•
•
•
•
•
•
•
•
2014
Ureter
Vase Difference
Ampula
Seminal Vesicle
Prostrate
Urethra
Epididimis
Testes
Prepuce
Male Reproductive system
2
Slide 3
Blood Testis Barrior• Tight junctions between adjacent
Sertoli Cells.
• This prevents large molecules
penetrating.
• Steroids can diffusebecause of fat
solubility.
• Fluid in seminiferous tubules is
different from plasma- low glucose and
protein. Rich in androgens, estrogens,
K+, inositol, glutamic acid and aspartic
acid.
2014
Male Reproductive system
3
Slide 4
Spermatogenesis
• Spermatogonia [Primitive
germ dells] begin mitotic
division.
• Primary spermatocytes
undergo meiotic [reduction]
division.
• Secondary spermatocytes
• Early Spermatids
• Late Spermatids- develop tail.
• Spermatozoa.
• The descendants remain tied
to Sertoli cell until the late
spermatid state.
• One spermatogonium – 512
spermatozoa [74 days].
2014
Male Reproductive system
4
Slide 5
Sperm.
• Head- chromosomal
material.
• Acrosome- cap on head,
rich in enzymes for
penetration corona radiata
and ovum.
• Proximal portion of the tail
is wrapped in a membrane
packed with mitochondria.
• Capability of motility
develops as it moves
through epididimis.
• Several inhibitory proteins
in the fluid inhibit motility
until ejaculation.
2014
Male Reproductive system
5
Slide 6
Effects of Temperature- 32°C
• Air circulating around the scrotum.
• Counter current exchange between
spermatic arteries and veins.
• Un-descended testes, testes wrapped
closely with body by tight bindersdegeneration and sterility.
• Hot baths- 43 – 45° for 30 minutes and
insulated supporters reduce sperm count
by 90 %.
2014
Male Reproductive system
6
Slide 7
Effect of Hormones.
• Leutinizing Hormone- stimulate Testosterone
secretion.
• Testosterone is essential for growth and division
of germinal cells.
• Follicular Stimulating Hormone- stimulates
Sertoli cells. Absence- no maturation of sperms.
• Estrogens produced by testis is also essential.
• Growth hormone and other hormones also
necessary.
2014
Male Reproductive system
7
Slide 8
Function of Seminal Vesicles.
• Secrets mucoid material with fructose, citric acid,
other nutrients, prostaglandins and Fibrinogen.
• Seminal vesicles empty their contents during
emission into ejaculatory duct.
• Prostaglandins may– modify cervical mucus for sperm motility and
– reverse peristalsis in uterus and fallopian tubes to
facilitate sperm motility.
• Largest volume contribution to the semen.
2014
Male Reproductive system
8
Slide 9
Function of the Prostate.
• Secrets thin milky fluid with calcium,
citrate, phosphate, a clotting enzyme and
profibrinolysin.
• Empties during emission by contraction of
the capsule and ads to bulk of the semen.
• Alkalinity essential to neutralize the acidity
of the seminal vesicular fluid and vaginal
secretions.
2014
Male Reproductive system
9
Slide 10
Semen.
•
•
•
•
•
•
Sperm and vas deferens fluid- 10 %
Fluid from seminal vesicle- 60 %
Fluid from prostate- 30 %.
The pH is 7.5, 2.5 to 3.5 ml.
Sperm count- 100,000,000 per ml.
Clotted on ejaculation [fibrinogen from seminal
vesicle and clotting enzyme from prostate]
• The coagulum dissolves in 15 to 30 minutes
[prostatic profibrinolysin activated]
• Life of ejaculated sperm is about 48 hours.
[storage in Vas deference 42 days]
2014
Male Reproductive system
10
Slide 11
Abnormalities of Spermatogenesis.
• Infections- bilateral orchitis due to mumps.
• Inborn degenerate tubular epithelia due to
strictures in genital ducts.
• Excessive temperature of the testes due to
failure to descend [cryptorchidism] and hot
environment.
2014
Male Reproductive system
11
Slide 12
Endocrine Function of Testes.
• Secretion of Testosterone-4-9 mg/day
• Transport- 98% in plasma is bound to protein.
• 65% bound β globulin- gonadal steroid binding
globulin.
• 33% bound to albumin.
• Plasma level- 300-1000 ng/dl [10.4-34.7 nmol/L]
in males, 30-70 ng/dl in females.
• Converted to 17-ketosteroiod and excreted in
urine.
2014
Male Reproductive system
12
Slide 13
Secretion of Testosterone and
Spermatogenesis.
2014
Male Reproductive system
13
Slide 14
Actions of Testosterone.
• Feed back control of LH secretion.
• Maintain spermatogenesis along with
FSH.
• Develop and maintain male secondary
sexual characteristics.
• Protein anabolic and growth promoting
effect.
2014
Male Reproductive system
14
Slide 15
Secondary Sexual Characteristics.
• External Genitalia
– Penis increases in length and width.
– Scrotum becomes pigmented and rugose with testicular
enlargement.
• Internal Genitalia.
– Seminal vesicles enlarge and secrete.
– Prostrate and bulbourethral glands enlarge and secrete.
• Voice becomes deeper– Larynx enlarges.
– Vocal cords increase in length and thickness.
• Body conformation– Shoulders broaden, all bones matrix increased.
– Narrow pelvic outlet, [male pelvis]
– Muscles enlarge [50% more than female].
2014
Male Reproductive system
15
Slide 16
Secondary Sexual Characteristics2.
• Hair growth–
–
–
–
Beard appears.
Anterior hair line recedes.
Pubic hair with male pattern [triangle with apex up]
Hair appears in axilla, chest, around anus and
increase in body hair.
– Scalp hair decreases.
• Skin– Sebaceous gland secretion thickens and increases.
– Increased melanin.
• Mental– More aggressive, active attitude.
– Interest in opposite sex.
2014
Male Reproductive system
16
Slide 17
Other Effects.
• Anabolic Effects.
– Growth rate increased by increased synthesis and
reduced breakdown of protein.
– Fusion of epiphysis- ? Estrogen [in males, conversion
of testosterone.]
– Moderate retention of sodium, potassium, calcium,
sulfate, and phosphate.
– Metabolic rate increased.
– Red cell count increased.
• Libido– Increased.
2014
Male Reproductive system
17
Slide 18
Production of Estrogens in Males
• 80 % of estradiol and 95 % of estrone in
plasma is formed by extragonadal
aromatization of circulating testosterone.
• The remainder comes from testes.
• Plasma estradiol- 20-50 pg/dl.
• Production increases with advancing age.
2014
Male Reproductive system
18
Slide 19
Functions of Testosterone During
Fetal Development.
• Testosterone is responsible for the
development of the male sex organs.
• Descent of testes.
2014
Male Reproductive system
19
Slide 20
Regulation of Gonadotropin and
Testosterone Secretion.
• Chorionic gonadotropin stimulates
secretion in fetus.
• GNRH from hypothalamus stimulates LH
and FSH from pituitary.
• Testosterone inhibits LH and Inhibin
inhibits FSH at both levels.
• Psychic factors through limbic system
influence GNRH secretion and sexual
functions- stress can inhibit.
2014
Male Reproductive system
20