spermatogenesis

Definition of spermatogenesis

formation of sperm cells

what is the basic structural unit of the testicle?

seminiferous tubules

What are the phases in order?

multiplication, growth, maturation, transformation, liberation

describe multiplication phase

PGCs travel into testicle and transform from Type A spermatogonia to Type B spermatogonia by mitosis

what are PGCs?

primordial germ cells

describe growth phase

Type B spermatogonia transform into primary spermatocytes by mitosis, meiosis 1 starts

describe maturation phase

primary spermatocytes transform to secondary spermatocytes by meiosis 1. Secondary spermatocytes transform to early spermatids by meiosis 2

what occurs during transformation phase

nucleus decreases, golgi apparatus forms acrosome, centrioles form flagellum. spermatid is now spermatazoa

describe liberation phase

spermatazoa (sperm cells) are released into the lumen of the seminiferous tubule (spermiation)

Where are the most mature sperm cells located?

in the center of the seminiferous tubule (lumen)

what is semen composed of?

spermatazoa and seminal plasma

what is the most mature form of a sperm cell?

spermatazoa

what is the most immature form of a sperm cell?

spermatagonia

how does a normal sperm cell move?

only forward

at least ___% of sperm cells should be normal

60