16.1

Male gonads : testes : produce make sex cells called sperm

Male reproductive system is found in the abdominal cavity

The reason makes have external gonads that hang outside the body is because the testis are a few degrees cooler than body temperature to allow for sperm development

Testis at body temp = no sperm

Once sperm is ready They get carried from testis by vas deferens to ejaculatory duct

Ejaculatory duct carries a combination of sperm and other Saminal fluids through the urethra

Urethra in males carries urine when not carrying sperm

Sphincter prevents the release of ursine when ejaculatory ducts are active they can enter open at the same time

Spermatogenisis: sperm formation , it takes place in the testes, I’m the seminiferous tube

Seminiferous tubules are lined with sperm producing cells called spermatigonia

Spermatoginia divides to form spermatocytes

Spermatocytes differentiate into spermatids Which have 23 chromosomes and this process takes 9-10 weeks

Steroli cells provide metabolic and mechanical support to developing spermatocytes cells

They also create a barrier between blood and seminiferous tubules, basically controlling hormones and nutrients to protect sperm tubules

Spermatids move to epididymis to mature n swim

Quality control is done by the epididymis

Seminal fluid required to give sperm something to swim in

Seminal fluids are secreted by three glands along the vas deference and ejaculatory duct

Seminal vesicles add fructose for source of energy for sperm, add prostaglandins for triggering contraction of smooth muscle along the reproductive tract to assist sperm I’m movement to egg

Prostate gland adds alkaline buffer to protect sperm from acidic environment in vagina

Cowpers gland adds mucus rich fluids before ejaculation to protect sperm from acids in urethra of male and also assists of sperm movement

primary sexual characteristics: directly involved in reproduction and are present at birth

Secondary sexual characteristics: external features that differ males from females but not involved in reproduction

Testosterone: primary male sex hormone

Produced in interstitial cells between seminiferous tubules

It signals maturation of testes, penis, and spermatogenesis

If signals development of secondary sex characteristics

Increases secretion of body oils

Hypothalamus and pituitary gland control spermatogenesis And male sex hormone levels, in testes

Hypothalamus releases GnRH to stimulate pituitary gland

Pituitary gland uses gonadotropic hormone to regulate testes

Two types of gonadotropins

Follicle stimulating hormone :FSH: spermatogenesis in seminiferous tubules

luteinizing hormone :LH: testosterone production in interstitial cells

Low testosterone stimulate hypothalamus to produce GnRH which activates pituitary to produce FSH and LH

Negative feedback comes from

sertoli cells : when they detect high sperm counts they release inhibin to inhibit FSH at pituitary gland and GnRH at hypothalamus

High testosterone: directly inhibits LH production at pituitary gland and indirectly inhibit by inhibiting GnRH at hypothalamus

Testes: Male gonads that produce sperm cells.

• Located in the abdominal cavity, external for temperature regulation (cooler than body temp for sperm development).

• Spermatogenesis occurs in seminiferous tubules: consists of spermatogonia → spermatocytes → spermatids in 9-10 weeks.

• Support Cells: Sertoli cells provide support and nutrients, also forming a blood-testis barrier.

• Transport: Sperm travels via vas deferens to the ejaculatory duct and through the urethra.

• Seminal Fluid: Composed of secretions from seminal vesicles (fructose, prostaglandins), prostate gland (alkaline buffer), and Cowper's gland (mucus).

• Hormonal Control: Governed by the hypothalamus (GnRH) and pituitary gland (FSH, LH), regulating testosterone and spermatogenesis.

• Feedback Mechanism: Sertoli cells release inhibin for high sperm counts; testosterone inhibits LH and GnRH levels.