Grade 12 Human Reproduction Part 1 Male reproductive organs Flashcards
What makes up the male reproductive organs?
- Primary sex organs - the testis / testes in scrotum
- Ducts - epididymis, sperm duct (vas deferens) and urethra
- Accessory glands e.g. prostrate
- External genitalia - penis
To simplify: Testes, Tubules for the transport of sperm, accessory glan
What is the scrotum and what is its function?
**A sac of skin that ecloses the testis.
**Functions: **
* Temperature regulator - keeping testis 2 - 3 degrees lower than body temperature ( for formation of fertile sperm).
* Protects the testis
What is the testis?
- Primary male sex organs - pair of **testes **
- Two oval structures, suspended outside the body in the scrotum
- Oval shaped gland, about 5cm in length
- Divided internally into compartments or small lobules
- Each lobule contains several closely packed, convoluted seminiferous tubules - 250m in each testis
- Tubules - lined with special cells, namely germinal epithelium.
- Epithelium cells can divide and give rise to sperm (male gametes) in a process called - spermatogenesis
- Between the tubules (connective tissue) are groups of endocrine cells - the interstitial cells / cells of Leydig = Produce male hormone testosterone
- A few germinal epithelium cells develop into l**arger columnar cells - Sertoli cells = provide food for sperm
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Discuss the function of the testis:
- Sperm production
- Testosterone - male sex hormone - development of secondary sexual characteristics
List the tubules for the transport of sperm (4)
- Epididymus
- Vas deferens (sperm duct)
- Ejaculatory duct
- Urethra
What is the epididymus?
Seminiferous tubules join to form the epididymis where they:
* mature to become motile and fertile
* are stored for several months (after which they are broken down by the epithelial cells of the epididymis and re-absorbed into the body
* situated at the back of the testes and lined with a mucous membrane
Explain the function of the epidiymis: (2)
- Stores sperm produced in testes - mature inside until ready to become motile and fertile and fertilise ovum
- Mucous membrane lining epididymis secretes a substance that, together with peristaltic movements of tubule walls, facilitate movement of sperm
What is the sperm duct / vas deferens?
- Muscular sperm duct = continuation of epididymis, which passes through abdominal cavity and opens in urethra
- Forms a swelling just before it joins the urethra = ampulla
What is hte function of the sperm duct / vas deferens?
- Transports sperm - by means of peristaltic movements, from epididymis to urethra
- Ejaculation
What is the ejaculatory duct?
The ampulla of the vas deferens leads to a muscular tubule, the ejaculatory duct.
What is the function of the ejaculatory duct?
The smooth muscle fibres in the duct contract, forcing the contents of the duct (semen) along the urethra to the exterior.
I.e. to ejaculate
What is the urethra?
The duct at the end of the uro-genital system leading to the exterior.
What is the function of the urethra?
- Forms a common duct for the transportation of semen and urine.
- These two processes never occur together.
LIst the accessory glands:
- Seminal vesicles
- Prostate gland
- Cowper’s glands
Explain seminal vesicles:
- Two sac-like structures connected by a tubule to the lower end of the ampulla.
- Lined with a mucous membrae that secretes a yellow-ish, sticky substance.