Structure of a Sperm
▪️ The body of sperm is covered by plasma membrane or cell membrane.
▪️ Sperm can be divided into 4 parts namely: head, neck, middle piece and tail. The haploid nucleus is present in the head. Acrosome is the cap-like structure of head which helps it to fertilize the ovum.
▪️ Acrosome is the cap-like structure present on the anterior-most end of the sperm head. It is filled with numerous enzymes like hyaluronic acid which are released upon encounter of egg in female oviduct. These enzymes function by digesting the membrane, thus allowing penetration of head and further release of male nuclei.
▪️ Mitochondria are present in the middle piece of the sperm. They are essential for producing energy required for movement of tail. This is essential for movement through the genital tract and oviduct before sperm encounters the egg. Rakesh might have less or poorly functional mitochondria, which prevent his normal count of sperms from moving along the genital tract.
▪️ Sperm count is essential as it determines the probability of a sperm encountering the egg. Sperm motility is essential to ensure the passage of sperms through the genital tract, uterus and oviduct. Sperm production rate determines the number of healthy coitus a male can have. Sperm height is not a determining factor of fertility.
▪️ Low sperm count leads to lesser amount of sperms entering the genital tract and passing successfully before encountering the egg in the oviduct. Thus less sperm count leads to lesser chances of fertilization and might result in infertility.
▪️ Seminiferous tubules are lined by spermatogonia and Sertoli cells. Spermatogonia undergo meiosis to produce sperm that are nourished by Sertoli cells.
▪️ Sperms are released out from seminiferous tubules facilitated by seminal plasma composed of secretions from epididymis, vas deferens, seminal vesicle, and prostate.
▪️ Seminal plasma helps in the motility and maturation of sperm. Secretions produce it from vas deferens, epididymis, seminal vesicle and prostate.
▪️ Testosterone secreted by Leydig cells stimulates spermatogenesis. It also acts on accessory ducts and glands and maintains their proper function. Release of sperms and semen is not coordinated by testosterone.
