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Male Reproductive System
• Aim: Understand the major structures of the male
reproductive system and explain the functions
Vocabulary: Penis, urethra, seminal vesicle, prostate
gland, urinary bladder, testis, epididymus.
•
Do Now: List 3 things you already know about the
male reproductive system.
The male reproductive system
• Three main functions:
– To produce gametes (the sperm cells)
– To produce hormones (testosterone)
– To deposit the sperm cells it produces inside the
female.
Male Reproductive System
External Genitalia
 Scrotum
 Divided sac of skin outside the abdomen
 Maintains testes at 3°C lower than normal body
temperature to protect sperm viability
Testes
 Function as sperm-forming
factories
 It produces hormones such as
testosterone
Hormones
Testosterone is the hormone that
1. stimulates the production of sperm
2. develops secondary sex characteristics
•deeper voices,
•bigger muscles,
•body and facial hair
Epididymis
 Functions to mature and
store sperm cells (at least
20 days)
 Expels sperm with the
contraction of muscles in
the epididymis walls to the
vas deferens
Sperm
Sperm: has
• head (genetic) with acrosome,
• midpiece (metabolic) containing mitochondria,
• tail (locomotor) which is a flagellum
Whole process of sperm formation takes 64-72
days.
2 - 6 ml ejaculate, 50 - 100 million sperm/ml
Processes of Spermatogenesis
 Spermatogenesis takes 64 to 72 days
Urinary bladder
•VAS DEFERENS
•SCROTUM
Seminal Vesicle
•PENIS,
•TESTIS,
•EPIDIDYMIS,
Urethra
•URETHRA,
•SEMINAL VESICLE,
•PROSTATE GLAND,
•URINARY BLADDER
Prostate Gland
Penis
Vas Deferens
Epididymus
Scrotum
Testis
http://kidshealth.org/parent/medical/body_basics/male_reproductive.html
Seminal Vesicles
 Located at the base of the bladder
 Produces a thick, yellowish secretion (60% of
semen) that contains:
 Fructose (sugar)
 Vitamin C
 Prostaglandins
 Other substances that nourish and activate sperm
Prostate Gland
 Encircles the upper part of the urethra
 Secretes a milky fluid
 Helps to activate sperm
 Enters the urethra through several small ducts
Urethra
 Extends from the base of the urinary bladder to the tip
of the penis
 Carries both urine and sperm
 Sperm enters from the ejaculatory duct
Semen
 Mixture of sperm and accessory gland
secretions
 Advantages of accessory gland secretions
 Fructose provides energy for sperm cells
 Alkalinity of semen helps neutralize the acidic
environment of vagina
 Semen inhibits bacterial multiplication
 Elements of semen enhance sperm motility