39-3 The Reproductive System Sexual Development
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
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39-3 The Reproductive System
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……..
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39-3 The Reproductive System
-These traits indicate sexual maturity
Male peacock with feathers
-They indicate sexual readiness
-They are used to attract partners.
Lion’s mane Deer antlers
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39-3 The Reproductive System 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.
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39-3 The Reproductive System
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39-3 The Reproductive System
Two main functions of the male reproductive system:
1. To make sperm (testes)
2. To deliver the sperm to the ova (penis)
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39-3 The Reproductive System
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.
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39-3 The Reproductive System
Space/cells between the seminiferous tubules is where the male produces his sex hormones.
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39-3 The Reproductive System
Inside the seminiferous tubules:
-walls are lined with 2N cells which produce sperm through the process of meiosis/spermatogenesis
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39-3 The Reproductive System
Meiosis/Spermatogenesis:
2N
Larger, mature
Primary spermatocyte
2N
Secondary spermatocytes
Spermatogonium
Produces four spermatids which will differentiate into sperm
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39-3 The Reproductive System
As spermatogenesis occurs, cell migrate from outer
Edges of tubes towards the center cavity.
120 to 200 million of sperm are produced per day
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39-3 The Reproductive System The Male Reproductive System
Male Reproductive System
Urinary bladder
Vas deferens
Pubic bone
Urethra
Penis
Epididymis
Testis
Scrotum
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Seminal vesicle
Rectum
Prostate gland
Bulbourethral gland
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39-3 The Reproductive System 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
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39-3 The Reproductive System
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.
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39-3 The Reproductive System
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
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39-3 The Reproductive System
An erection is caused by this increase in blood flow~ causing the penis to swell and elongate.
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39-3 The Reproductive System 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.
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39-3 The Reproductive System 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.
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39-3 The Reproductive System
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
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39-3 The Reproductive System The Male Reproductive System
A sperm cell consists of:
Acrosome
a head, which contains the 1N nucleus
Nucleus
Acrosome: top of head which contain specialized lysosomes which release enzymes used to dissolve protective layer around egg so fertilization can take place.
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Mitochondria
Tail
Head
Midpiece
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39-3 The Reproductive System
-a tail/flagella, which propels the cell forward
-a midpiece, which contains energy-releasing mitochondria
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Midpiece with mitochondria
Flagella/tail
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