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39-3 The Reproductive System
Slide 1 of 41
Copyright Pearson Prentice Hall
What is the true differences between males and females??????
Primary sex characteristics: Are structures directly involved in reproduction.
Males: Testes and penis
Females: Ovaries and uterus
Sexual Development
39-3 The Reproductive System
Slide 2 of 41
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Secondary Sex Characteristics: -Characteristics which evolve in
humans through the production of hormones.
-Distinguishes males from females. Examples: pubic hair, beards, distribution of fat, change in voice, breast development……..
39-3 The Reproductive System
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-These traits indicate sexual maturity
-They indicate sexual readiness
-They are used to attract partners.
Lion’s mane Deer antlers
Male peacock with feathers
39-3 The Reproductive System
Slide 4 of 41
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Sexual Development
Puberty is a period of rapid growth and sexual maturation during which the reproductive system becomes fully functional.
When puberty ends, reproductive organs are fully developed.
Puberty usually begins between the ages of 9 and 15, and usually starts one year earlier in females than in males.
39-3 The Reproductive System
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Male Reproductive System
Copyright Pearson Prentice Hall
39-3 The Reproductive System
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Two main functions of the male reproductive system:
1. To make sperm (testes)
2. To deliver the sperm to the ova (penis)
39-3 The Reproductive System
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Sperm production takes place in the 2 testes-produces sperm and male hormones-located in scrotum
-sack outside body cavity-reduces temperature by 2 to 4
degrees for optimal temperature for healthy sperm production
-each testicle is made up of 200 meters of coiled tubing called seminiferous tubules.
39-3 The Reproductive System
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Space/cells between the seminiferous tubules is where the male produces his sex hormones.
39-3 The Reproductive System
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Inside the seminiferous tubules:
-walls are lined with 2N cells which produce sperm through the process of meiosis/spermatogenesis
39-3 The Reproductive System
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Meiosis/Spermatogenesis:
2N 2N
Spermatogonium
Larger, maturePrimary spermatocyte
Secondary spermatocytes
Produces fourspermatids whichwill differentiateinto sperm
39-3 The Reproductive System
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As spermatogenesis occurs, cell migrate from outerEdges of tubes towards the center cavity.
120 to 200 million of sperm are produced per day
39-3 The Reproductive System
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The Male Reproductive System
Male Reproductive System
Urinary bladder
Vas deferens
Pubic bone
Urethra
Penis
Seminal vesicle
Rectum
Prostate gland
Bulbourethral gland
Scrotum
Testis
Epididymis
39-3 The Reproductive System
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The Male Reproductive System
Once sperm are produced in the seminiferous tubules they move into a sac called the epididymis, where they mature and are stored for up to 5 days
39-3 The Reproductive System
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Sperm can be used/released by an ejaculation or their lysosomes will break open and digest the sperm so it can be disposed of as a waste product.
39-3 The Reproductive System
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Sperm Delivery:
-main organ of sperm delivery is the penis-during an sexual excitement the spongy material which makes up the penis fills with blood.-Spongy material is called glans penis
39-3 The Reproductive System
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An erection is caused by this increase in blood flow~ causing the penis to swell and elongate.
39-3 The Reproductive System
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The Male Reproductive System
From the epididymis, sperm move into a tube called the vas deferens, which extends up from the scrotum to the penis.
39-3 The Reproductive System
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The Male Reproductive System
As sperm travel through the vas deferens it encounters three glands which adds fluid to the sperm creating semen:
-Seminal vessicle: adds citric acid which activates the sperm.
-Prostrate gland: adds fructose, a sugar used for energy by the sperm.
-Cowpers gland: adds a basic fluid which neutralizes the
acid in the females vagina.
39-3 The Reproductive System
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The two vas deferens converge into one main tube, the urethra.
The urethra travels through shaft of penis.
Semen travels at a rate of 200 ft/second and exits out urethra with an ejaculation
39-3 The Reproductive System
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The Male Reproductive System
A sperm cell consists of:
• a head, which contains the 1N nucleus
• Acrosome: top of head which contain specialized lysosomes which release enzymes used to dissolve protective layer around egg so fertilization can take place.
Head
Nucleus
Midpiece
Mitochondria
Tail
Acrosome
39-3 The Reproductive System
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Copyright Pearson Prentice Hall
-a tail/flagella, which propels the cell forward
-a midpiece, which contains energy-releasing mitochondria
Flagella/tail
Midpiece withmitochondria
