spermatogenesis

Definition of spermatogenesis

formation of sperm cells

gametogenesis definition

formation of gametes

what 2 characteristics do gametes have to have to perform their function

functional cytodifferentiation (two different cells that have differentfunctions)

1/2 number of chromosomes

what is the basic structural unit of the testicle?

seminiferous tubules

Where are the most mature sperm cells located?

in the center of the seminiferous tubule (lumen)

What are the phases of spermatogenesis in order?

multiplication, growth, maturation, transformation, liberation

what happens in the multiplication phase

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

what are PGCs?

primordial germ cells - origin of gametes

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)

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

spermatogonia is:

diploid

compensable vs non compensable abnormalities

compensable - does not affect function and genetic material

uncompensable - affects function and genetic meterial