Ch 12: Human Reproduction Males

Outer Genitalia

• default is female in absence of SRY gene

• gen SRY is present on Y chromosome and produces testosterone

Inner Genitalia

• testes - males

• ovaries - females

Spermatogenesis (MEIOSIS)

the production of mature sperm cells from spermatogonium in testes

• continuous and prolific process in the adult male

• each ejaculation contains100-650 million sperm

• occurs in seminiferous tubules

• as spermatogenesis progresses, the developing sperm cells move from the wall to the lumen of a seminiferous tubule

• a large number of mitochondria provide ATP to power the flagellum

Structure of Male Reproductive Organ

• seminal vesicle

• prostate gland

• bulbourethral gland

Seminal Vesicle

where meiosis forms sperm

• secretes mucus that contains a molecule that encourages contractions in the smooth muscle of the uterus and glucose to power the flagellum of sperm

Prostate Gland

thin milky fluid that provide mobility and viability to the sperm

Bulbourethral Gland

produces fluid that neutralizes the pH of the urethra before ejaculation

What is the primary goal of sperm?

to find and penetrate an egg

Structure of Sperm

• tipped with an acrosome (contains enzymes that help sperm penetrate the egg)

• haploid nucleus

• spiral mitochondria

• tail (flagellum and sheath)

Hormonal Control of Sperm

• hormones are transported through the blood

• GnRH is produced in the hypothalamus and goes through the blood to the pituitary gland

• this produces 2 hormone:

  • follicule stimulating hormone (FSH)

  • luteinizing hormone (LH)

• too much testosterone will make the brain stop producing GnRH, FSH, and LH

Follicule Stimulating Hormone (FSH)

stimulates spermatogenesis (meiosis)

Luteinizing Hormone (LH)

tells testes to produce testosterone