The male reproductive system

                                                                    Human Reproduction        

Introduction

   Reproduction is an essential feature of all living organisms and is the process by which an individual multiplies in number by producing more individuals of its own type.

                                                           

                                                                The male reproductive system

    The male reproductive system includes 

•  Pair of testes 

            alongwith

• Accessory ducts
• Glands
• External genitalia

                                                                                    Testes

1. The testes are situated outside the abdominal cavity within a pouch called scrotum.

Function of scrotum

• The scrotum helps in maintaining the low temperature of the testes (2-2.5℃ lower than the normal internal internal body temperature)
• The lowering of temperature is necessary for spermatogenesis.

     2. In adults, each testis is oval in shape

• Length = 4 to 5 cm
• Width = 2 to 3 cm

     3. Each testis has about 250 compartments called testicular lobules. Each lobule contains one to three highly coiled seminiferous tubules in which sperms are produced. Each seminiferous tubule is  lined on its inside by two types of cells called 

                                                 

                                     1. Male germ cells                                             2. Sertoli cells.

1. Male germ cells

•     The male germ cells undergo meiotic divisions finally leading to sperm formation.

2. Sertoli cells

• Sertoli cells provide nutrition to the germ cells.

     4. The regions outside the seminiferous tubules called interstitial spaces, contain small blood vessels and interstitial cells or Leydig cells.

•        Leydig cells =  Leydig cells synthesise and secrete testicular hormones called androgens.

                                                                 Accessory ducts

• The male sex accessory ducts include 

1.   Rete testis

• The seminiferous tubules of the testis open into the vasa efferentia through rete testis.

      2. Vasa efferentia

• The vasa efferentia leave the testis and open into epididymis located along the posterior surface of each testis.

      3. Epididymis

• The epididymis leads to vas deferens.

      4. Vas deferens

• The epididymis leads to vas deferens that ascends to the to the abdomen and loops over the urinary bladder. 
• It receives a duct from seminal vesicle and opens into urethra as the ejaculatory duct.
• These ducts store and transport the sperms from the testies to the outside through urethra.

                                                                     
                                                                              Glands

• The  male accessory glands include paired seminal vesicles, a prostate and paired bulbourethral glands.
• Secretions of these glands constitute the seminal plasma which is rich in fructose, calcium and certain enzymes.
• The secretions of bulbourethral glands also helps in the lubrication of the penis.