The Male Reproductive System Mader Chapter 15.1

The male urogenital system

The urogenital tract The beginning: Testes—produce sperm and interstitial cells produce male sex hormones. Seminiferous tubules—produce sperm. (packed with cells undergoing spermatogenesis) Epididymis—stores sperm while they mature. 15-3

The male urogenital system

The urogenital tract-Cont. Seminal vesicles—produce a sugary alkaline fluid which buffers the sperm against acids in the female reproductive tract. Prostate gland—contributes a milky alkaline fluid to semen. Bulbourethral glands—secrete a slippery alkaline fluid which lubricates the urethral canal. Vas deferens—transport sperm to the urethra. 3.5 ml of ejaculate may contain as many as 400 million sperm which live about 48 hours in the female reproductive tract. 15-5

The testis- in detail

Seminiferous tubules

Spermatozoon

The male gamete - spermatozoon Sperm (spermatozoa) Acrosome—stores enzymes needed to penetrate the egg. Head—contains the nucleus with 23 chromosomes. Midpiece—mitochondria provide energy for movement. Tail—flagellum for movement. 15-7

The male pituitary gonad axis Releasing hormone Negative feedback

The male gonad-pituitary axis Hormonal Regulation in Males: Follicle-stimulating hormone (FSH)—promotes the production of sperm. Luteinizing hormone (LH)—controls the production of testosterone. Testosterone—essential for normal development and functioning of the male reproductive organs. 15-8