REPRODUCTIVE SYSTEM.
Sperm:-
Significance:-continuity of species
-heredity characters are conveyed from parents to offspring through a wide DNA range.
Male reproductive system.:-
Primary sex organ:-testis
-function-spermatogenesis,
-secretion of sperms.
Spermatogenesis:-physiological process of production of matured haploid sperm from diploid spermatogonial cells
Site:-seminiferous tubule
-starts from puberty till death
-normal count-100-200million/ml semen
If the count is less than 20 million/ml causes sterility
Stages of spermatogenesis:-
1)spermatogonia(2n)
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|(multiplication-step 1)
Primary spermatocytes(2n)
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|(reduction- step 2)
Secondary spermatocyte(n)
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Spermatid (n)-non mitotic differentiation-step 3)
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Spermatozoa {(n) mobile
Factors affecting spermatogenesis:-
1)Temperature-should be maintained between 2-4 degree celsius
For the surviving of sperm the scrotum is kept outside in mammalian body
Descent of testis-occurs in in intrauterine life ie,7 month of pregnancy and continues upto9 mouth
Non descend -cryptorchidism
2)Varicose vein in scrotum-decrease in sperm increases temperature.
Hormones-a)LH-acts on leydig cells in testis-testosterone.
b)FSH -differentiation of spermatid -sperm
c)inhibition-inhibits FSH -regulation of spermatogenesis.
d)testosterone-spermatogenesis,growth development,maturation of sperms.
3)Malnutrition:-protein energy malnutrition-kwashiorkor-decrease in sperm count
4)Exposure to x rays,radiation-decrease sperm count
5)Excessive alcohol-decreases sperm count in case of mumps and typhoid fever.
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