The system in the male body that produces, stores, transports and expels sperm is called the ejaculatory system. Different parts of human reproductive system are-
1. Testis: The main organ of the reproductive system is the testis. There are two hanging scrotums or scrotums at the thigh joint. The left scrotum is larger and the right smaller. The testicles are located inside the scrotum. Each testicle is oval and partially flattened. Its length is 2 inches and weight is 10-12 grams.
Each testicle is covered by 3 integuments. Tunica vaginalis, tunica albuginea and tunica vasculosa testis. The outer layer is the tunica vaginalis, the middle layer is the tunica albuginea and the inner layer is the tunica vasculosa.
Each testicle divides into 250 cells or segments. Each segment contains 1-4 patchy seminiferous tubules. Each testicle contains about 1000 seminiferous tubules. A seminiferous tubule is about 500 mm long.
Many seminiferous tubules join together to form a straight duct. The straight ducts join to form the reti testis. The reti testes join together to form the vas deferens or vasa efferentia.
Function of Testis
(i) Produces sperm.
(ii) Secretes the hormone testosterone.
2. Epididymis: The seminiferous tubules or vasa efferentia of each testicle combine to form the epididymis. It is located at the posterior end of the scrotum and is a coiled duct. Its length is 4-6 meters. Its tail portion is straight and meets the vas deferens.
Function of Epididymis
(i) It separates liquid and solid waste from sperm.
(ii) It increases fertility.
(iii) It stores sperm.
(iv) It keeps the sperm fresh by secreting nutrients.
3. Vas deferens: The tube extending from the end of the epididymis to the root of the urinary bladder is called the vas deferens. It is 40-50 cm long. It forms the ampulla after crossing the urethra.
Function of Vas deferens
(i) It transports sperm.
(ii) It stores sperm.
4. Seminal vesicle: The end of the spermatic cord swells and forms a small, long, muscular and curly bag like a finger is called seminal vesicle or sperm. It produces seminal fluid of which 70% constitutes semen.
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(i) It produces cement.
(ii) secretes copious amounts of mucus to produce sperm or semen.
(iii) It produces fructose to nourish the sperm.
5. Ejaculatory duct: The short duct formed by sperm and seminal vesicles is called ejaculatory duct. It is 19 mm long and 0.3 mm in diameter.
Function: It transports the sperm to the urethra.
6. Urethra: A common tube of the excretory and reproductive system is the urethra. It is 20 cm long. It opens at the apex of the penis.
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(i) It increases the volume of semen by secreting alkaline fluid.
(ii) It preserves the spermatozoa by mitigating the acidic environment.
(iii) It provides nutrition to spermatozoa.
7. External genitalia
(i) Scotum: Two scrotums are suspended between the two thighs. The fluid in the scrotum is called a hydrocele. It maintains a favorable temperature for sperm production. Protects testicles from stress.
(ii) Penis: The soft and muscular organ through which the urethra opens to the outside is called the penis. The base of the penis is called the glans penis, the hanging part is called the glans penis, the red umbrella-like tip is called the glans penis and the tip or foreskin is called the prepuce. Muslims and Jews had their foreskins cut off. The penis is made up of elastic muscles called corpora cavernosa and corpora spongiosum. It is stiff and straight when excited.
8. Reproductive gland
(i) Prostate gland: It is a pear shaped gland. Consists of two parts. base and top. Its wall is composed of muscular and glandular cells. Glandular secretions are released into the urethra.
Work:
* It increases the volume of semen by secreting alkaline fluid.
* It keeps the sperm alive by soothing the acidic environment.
(ii) Bulbourethral of Cowper’s gland: On either side of the urethra there are two pea-like Cowper’s glands. They join the urethra.
Action: It secretes a slippery mucous substance during intercourse and makes the vagina slippery.