The document summarizes the male reproductive system. It describes the external anatomy including the penis and scrotum. Internally it discusses the testes, epididymis, ductus deferens, and accessory sex glands. Spermatogenesis and the role of hormones like testosterone are explained. Ejaculation involves emission of semen from the epididymis, vas deferens and accessory glands into the urethra, then expulsion during orgasm.

1. Hormonal Control of Male
Reproductive System
By:
Andisa Shabrina (3425122214)
Putri Ajeng Sariyanti (3425122216)

2. Reproductive Anatomy of the Human Male.
 External:
- penis
- scrotum
 Internal:
- gonads
- epididymis and ductus deferens
- accessory sex glands and ducts.
Human reproduction involves intricate
anatomy and complex behavior

3. Male Reproductive System

4. Male Reproductive System

5. The three parts of the penis:
1. The root, which is
attached to the abdominal
wall.
2. Part of the body or trunk.
3. The glans, the tip of the
penis is shaped like a cone.
The penis is composed of spongy
erectile tissue.
PENIS

6. Testes

7. Testes are the male gonads.
 Seminiferous tubules- form sperm
 Leydig cells (interstitial cells)- produce androgens
(ex. Testosterone, ABP).

8. Testes are located in the scrotum,
outside the body cavity.
 This keeps testicular temperature cooler
than the body cavity.
 The testes develop in the body cavity and
descend into the scrotum just before birth.

9. Epididymis and Ductus Deferens
• The epididymis (sperm maturation)
The epididymis is a meandering channel in the
scrotum which is out of the testes. The epididymis
numbered pair of right and left. The epididymis
serves as a temporary storage of sperm to a
sperm to mature and move to the vas deferens
• The vas deferens (sperm ducts of the testis
into the pockets of sperm)
Vas deferens or sperm duct (ductus deferens) is a
straight channel that leads to the top and is a
continuation of the epididymis. The vas deferens
serves as a channel through which the course of
sperm from the epididymis to the seminal sac or
bag of cement (the seminal vesicles).

10. Semen
Seminal fluid is thick, yellowish, and alkaline.
 It contains mucus, fructose, a coagulating
enzyme, ascorbic acid, and prostaglandins.
Accessory glands:
1. seminal vesicle
2. prostate gland
3. bulbourethral gland

11. Seminal Vesicle
Seminal vesicle:
• A pair of glands that secrete a liquid
component of semen into the vas deferens.
• Secretion is alkaline
• Contains fructose, asorbic acid, coagulating
enzyme, prostaglandin

12. Prostate gland:
• Location- surrounds and opens into the urethra where it
leaves the bladder.
• Secretion- slightly alkaline fluid that activates the sperm
and prevents them from sticking together
 Prostate problems are common in males over 40.
 Prostate cancer is one of the most common cancers
in men.
Prostate

13. Bulbourethral gland (Cowper’s gland):
• Location- paired glands that lie beneath the prostate
• Secretion- a thick, clear alkaline mucous that drains into
the membranous urethra.
• Function- It acts to wash residual urine out of the urethra
when ejaculating semen-- raises pH; neutralizes acidity of
urine.
Bulbourethral
gland

14. Spermatogenesis

15. The Stages of Spermatogenesis
Spermatogenesis occurs after the puberty.
The stages of spermatogenesis:
- Proliferation / mitotic: spermatogonia /
germinal epithelial cells 
spermatocytes
- Meiotic division: primary spermatocyte 
secondary spermatocytes 
spermatid
- Spermiogenesis: spermatids  spermatozoa
This process occurs for 75 days.

16. Mature Spermatozoa
tail
mitochondria
nucleus
acrosome
head

17. Glands and Male Reproductive Hormones
Glands Hormone
Hypothalamus Gonadotropin Releasing
Hormon (GnRH)
Pituitary
anterior
Gonadotropin (FSH dan
LH/ICSH)
Gonad: Testis Testosteron dan inhibin

18. Male Hormones Control
• Gonadotropin
– Produced by pituitary & regulates testis
• FSH (Follicle-Stimulating Hormone)
– Stimulates sperm production in seminiferous tubules
• LH (Luteinizing Hormone)
– Production of testosterone by interstitial cells
• GnRH (Gonadotropin-Releasing Hormone)
– Stimulates pituitary to release FSH and LH
– Secreted by hypothalamus during puberty

19. Pituitary- Hypothalamic Associations
www.cushings-help.com/ anterior-pituitary.gif

20. Male Reproductive
System
• Hormones of brain-testicular
axis
– anterior pituitary drives changes
during puberty
• controlled by GnRH from
hypothalamus
• begins to secrete FSH, LH
– LH – targets Interstitial
endocrinocytes
• testosterone
• dihydrotestosterone (DHT)
– FSH - Sustentacular cells
• Androgen-Binding Protein (ABP)
concentrates androgens for
spermatids
• Inhibin – negative feedback to
the pituitary and hypothalamus

21. Male Reproductive
System
• Development
– testosterone stimulates
pattern development before
birth (internal ducts)
– DHT  external genitals
– estrogens from testes  brain
development
• Puberty – testosterone & DHT
stimulate enlargement of
male sex organs and
secondary sexual
characteristics

22. Male Reproductive System
• Testosterone -
– secondary sex characteristics:
• muscular, skeletal growth
– heavier, thicker muscles and bones in men than in
women
– also triggers epiphyseal closure
• pubic, axillary, facial and chest hair
• oil gland secretion
• larynx enlargement  deepening the voice
– sexual functions
• male sexual behavior and aggressive behaviors
• Spermatogenesis
• sex drive in both male and female
– Anabolism

23. Hormonal
Control Of
Spermatoge-
nesis
Copyright 2009, John Wiley & Sons, Inc.

24. Hormonal Feedback and the Regulation
of the Male Reproductive Function

25. Copyright 2009, John Wiley & Sons, Inc.
Hormonal control of testes
– At puberty, secretion of gonadotropin-releasing hormone (GnRH)
increases
– Stimulates anterior pituitary to increase secretion of luteinizing
hormone (LH) and follicle-stimulating hormone (FSH)
– LH stimulates Leydig cells to secrete testosterone
• Synthesized from cholesterol mainly in testes
• Suppresses secretion of LH and GnRH via negative feedback
• Enzyme 5 alpha-reductase converts testosterone into dihydrotestosterone
(DHT) in external genitals and prostate
– FSH acts indirectly on spermatogenesis
• FSH and testosterone act on Sertoli cells to stimulate secretion of
androgen-binding protein (ABP)
• ABP binds testosterone keeping concentration high
• Testosterone stimulates spermatogenesis
• Sertoli cells release inhibin which inhibits FSH

26. Ejaculation
• A male usually ejaculates about 2 – 5 mL of semen; each
milliliter containing about 50 – 130 million sperm.
• Bulbourethral fluid also carries some sperm released before
ejaculation.
• Ejaculation propels sperm from the epididymis to the vas
deferens.
• The vas deferens run from the scrotum and behind the
urinary bladder.
• Here each vas deferens joins with a duct from the seminal
vesicle to form an ejaculatory duct.
• The ejaculatory ducts open into the urethra.
• The urethra drains both the excretory and reproductive
systems.

27. Ejaculatory Ducts
– formed by ducts
from seminal vesicle
and ductus deferens
– move sperm into
prostatic urethra
before ejaculation

28. Male Reproductive System
• Erection
– Arteries dilate with
sexual stimulation, a
parasympathetic reflex
– Large quantities of blood
enter the sinuses
• compress superficial veins
from sinuses
• trapped blood 
erection
– Close bladder sphincter
• prevent urine flow
• prevent semen backflow
 Ejaculation
 Sympathetic reflex
 Peristalsis
 Arteries constrict, capillary sinuses
empty

29. • Erection
– Penis hardening soft under normal circumstances in order to get
into the vagina
– Swelling of the erectile tissue of the penis by the blood as a
result of intense arteriolar vasodilation triggered by penile
parasympathetic stimulation and mechanical stress vein
• Emission
– Emptying the sperm and glandular secretions additional sex
(semen) into the urethra
– Contraction of smooth muscle in the walls of the ducts and
extra sex glands triggered by sympathetic stimulation
• Expulsion
– Charging urethra in cement
– Contraction of skeletal muscle in the base of the penis that is
triggered by motor neurons