male reproductive system.txt

aka testes: produce sperm & secrete hormones

• Epididymis: site of sperm maturation
• ductus deferens
• ejaculatory ducts
• urethra
• AID in transport and storing sperm, assisting their maturation and conveying them to exterior

• Seminal vesicles
• prostate
• bulbourethral glands
• AID in adding secretions to semen

Scrotum supports testes & penis delivers sperm to female reproductive tract

• Internally divides scrotum into 2 sacs, each w/single testis
• Made of subcutaneous layer & dartos muscle
• Cremaster muscle is associated w/each testis

• Require 2-3celcius below core body temp to grow
• Cremaster & dartos muscle contract or relax to help achieve this

• Sperm produced here thru SPERMATOGENESIS
• Each of 200-300 lobules contain 1-3 seminiferous tubules

primary spermatocytes -> secondary spermatocytes -> spermatids -> sperm cells -> lumen

• Support cells through:
• nourishing spermatocytes, spermatids & sperm
• Phagocytizing excess spermatid cytoplasm
• Controlling movements of spermatogenic cells
• Releasing sperm into lumen
• Produce fluid for sperm transport
• Secrete Inhibin
• Regulate effects of Testosterone & FSH

• found between seminiferous tubules
• Help secrete Testosterone

• Takes 65-75 days
• 1. spermatogonia (2n): Sperm undergo mitosis & some development
• 2. primary spermatocytes (2n): each duplicates its DNA
• 3. Meiosis 1 (n): homologous pairs line up, crossing over occurs. 2 haploid cells at end of Meiosis 1..each chromosome has 2 chromatids
• 4. Meisosis 2 (n): the 2 chromatids seperate into spermatids form (4 haploid cells)
• cells remain attached by CYTOPLASMIC Bridges
• 5. Spermiogenesis: spherical spermatids into elongated SPERM. Acrosome and flagella form, mitochondria multiply.
• Sertoli cells dispose of excess cytoplasm
• Spermiation: releasing from connections to Sertoli cells
• sperm not yet able to swim

300mil sperm

48hrs

• Head:
• contains nucleus & 23 chromosomes (haploid - n). Acrosome also here - a vesicle with oocyte penetrating enzymes.
• Tail:
• neck contains centrioles forming microtubules comprising remainder of tail
• Middle piece has mitochondria
• Principle piece is longest portion
• End piece is the terminal portion

• secretion of GnRH INCREASES
• stimulates anterior pituitary to INCREASE secretion of LH and FSH
• LH stimulates Leydig cells to secrete testosterone...which suppresses further LH & GnRH (via neg feedback)
• Testosterone is then converted to DHT via Enzyme 5 alpha-reductase
• FSH and testosterone act on SERTOLI cells to stimulate secretion of androgen-binding protein (ABP)
• Sertoli cells release INHIBIT, inhibiting FSH
• Testosterone stimulates spermatogenesis

• DHT: stimulates Devel. of EXTERNAL genitalia
• stimulate devel. of male sex characteristics (organs & 2ndary sex char @ puberty)
• contribute to male sex BEHAVIOR
• contribute to Spermatogenesis
• Contribute to Sex DRIVE (libido)

• Site of sperm maturation: where it acquires motility & ability to fertilize
• Sperm storage (for several months)
• Continues on as ductus (vas) deferens

• Conveys sperm during arousal thru peristaltic contractions
• Sperm storage (for several months)

• Union of ducts from seminal vesicle & ampulla of ductus (vas) deferens
• ends in Prostatic urethra
• Ejects sperm & seminal vesicle secretions just before release of semen into urethra

• shared terminal duct of reproductive & urinary systems
• Ends @ urethral orifice

• contain 60% of semen volume
• Secrete alkaline fluid (contains fructose, clotting proteins from blood)

• contains 25% of semen volume
• Secretes milky, acidic fluid (citric acid, proteolytic enzymes, acid phosphatase & seminalplasmin (antibiotic)

• Secretes alklaine fluid that PROTECTS passing sperm by NEUTRALIZING acids from urine (in urethra)
• Mucus lubricates end of penis & lining of urethra

• Parasympathetic fibers release & cause local production of Nitric oxide (NO)
• NO causes smooth muscle in arterioles to RELAX & dilate, allowing large amounts of BLOOD to enter penis.