CHAPTER 22: THE REPRODUCTIVE SYSTEMS
IV.ORGANS OF THE MALE REPRODUCTIVE SYSTEM
5.Sperm Structure: See Fig 22.10, and Fig 22.12, page 889.
The structure of a mature sperm cell consists of a head, a body, and a tail:
contains 23 chromosomes and
is covered by a helmet like structure called an acrosome.
1.contains enzymes to help penetrate the oocyte.
b.The body (mid-piece)
contains many mitochondria needed to produce ATP for energy for the sperm cell to complete its long journey;
is a flagellum
provides locomotion for the sperm cell.
See gray box on page 888 concerning toxic chemicals that affect a sperm's ability to swim.
6.Hormonal Control of the Testes: Fig 22.18, page 897.
a.At puberty, the hypothalamus secretes a "" that target the male’s anterior pituitary gland;
b.The anterior pituitary gland then secretes two gonadotropins:
Follicle stimulating hormone (FSH), which stimulates spermatogenesis in the germinal epithelium of Seminifierous tubules (ST’s); and
Luteinizing hormone (LH), which stimulates the interstitial cells between the ST's to produce male sex hormones.
c.Male Sex Hormones = Androgens
Testosterone is the major androgen whose production begins at puberty:
Testosterone targets the secondary sex organs of the male:
facial, axillary, and inguinal hair follicles.
bone and muscle
vocal cords of larynx.
Actions include development of male secondary sexual characteristics at puberty and then maintenance throughout life
1.increased growth of body hair;
3.increased muscular growth;
4.strengthening of bones.