16.1

Testes

Male gonads that produce sperm cells.

Function of Male Gonads

Produce male sex cells called sperm.

Spermatogenesis

The process of sperm formation that occurs in the seminiferous tubules.

Seminiferous Tubules

Structures in the testes lined with sperm-producing cells called spermatogonia.

Spermatogonia

Cells that divide to form spermatocytes during spermatogenesis.

Spermatocytes

Cells that develop from spermatogonia and differentiate into spermatids.

Spermatids

Cells that have 23 chromosomes and are the end result of spermatocyte differentiation.

Epididymis

Location where spermatids mature and gain the ability to swim.

Seminal Fluid

Fluid required for sperm transport and survival, secreted by several glands.

Seminal Vesicles

Glands that add fructose and prostaglandins to seminal fluid.

Prostate Gland

Gland that adds an alkaline buffer to protect sperm from the acidic environment.

Cowper's Gland

Gland that provides mucus-rich fluids to protect sperm and assist in movement.

Primary Sexual Characteristics

Directly involved in reproduction and present at birth.

Secondary Sexual Characteristics

External features that differentiate males from females but are not involved in reproduction.

Testosterone

Primary male sex hormone produced in interstitial cells.

Hypothalamus and Pituitary Gland Control

Controls spermatogenesis and male hormone levels, releasing GnRH and gonadotropins.

Follicle Stimulating Hormone (FSH)

Gonadotropin that stimulates spermatogenesis in seminiferous tubules.

Luteinizing Hormone (LH)

Gonadotropin that stimulates testosterone production in interstitial cells.

Negative Feedback Mechanism

System where Sertoli cells release inhibin to decrease FSH and GnRH when sperm counts are high.

Sertoli cells

Support cells in the seminiferous tubules that nourish developing spermatocytes and form a blood-testis barrier.

Blood-Testis Barrier

Barrier formed by Sertoli cells to separate developing sperm from the blood.