The Reproductive System - Male

Overview http://www.lakemichigancollege.edu/dept/Arts-Sciences/bio/anat/mapmale.html http://www.ehow.com/video_4399181_overview-male-reproductive-anatomy.html

Describe the macroscopic and microscopic anatomy of the testes. Testes descend into the scrotal sacs during the last 2 months of fetal development Sterility is possible if they don’t descend (T° is 3° cooler & closely held when cold outside)

The sperm path Seminiferous tubule  epididymis  vas deferens  bladder loop to empty into urethra  3 glands add fluids  ejaculation

Sagittal view of testis Each testis is divided into lobules Each lobule contains 1-3 seminiferous tubules

Lobules contain a network of ducts leading to efferent ductules

Tubular events Each tubule is packed with cells undergoing spermatogenesis Spermatogonia lie just inside of the outer wall of a tubule Newly formed spermatogonia move away form the outer wall, grow  1° spermatocytes  meiosis II  spermatids  spermatozoa (sperm) Sertoli cells (“nurse” cells support, nourish & regulate spermatogenic cells)

http://www. google. com/imgres. imgurl=http://nhscience. lonestar http://www.google.com/imgres?imgurl=http://nhscience.lonestar.edu/biol/reproductive/testis.jpg&imgrefurl=http://nhscience.lonestar.edu/biol/reproductive/testis.htm&usg=__3qlBoypAU92zPsrDfNr8rP9ll4Y=&h=360&w=486&sz=45&hl=en&start=6&zoom=1&itbs=1&tbnid=0N52sXisCeHWIM:&tbnh=96&tbnw=129&prev=/images%3Fq%3Dcross%2Bsection%2Bseminiferous%2Btubule%26hl%3Den%26gbv%3D2%26tbs%3Disch:1

Testosterone Secreted by interstitial cells Called Leydig cells - named after the German anatomist Franz Leydig, who discovered them in 1850

Epididymides Sperm storage – 17 ft of tightly coiled tubule Just outside of testis

Epididymis joins with vas deferens

Vas deferens ascends through inguinal canal to enter the abdomen… ..where it curves around the bladder & empties into the urethra

Spermatic cords – fibrous connective tissue & muscle fibers enclose the vas deferens… … the blood vessels & nerves

Inguinal hernia – where cord enters abdomen

Seminal fluid aka semen 3 types of glands add secretions to s.f. Seminal vesicles –base of bladder Prostate gland - upper portion of urethra Bulbourethral (Cowper’s) glands – posterior to prostate on either side of urethra

tail, middle piece, head 1n = 23 chromosomes flagella mitochondria acrosome

Name the glands and describe the secretions that contribute to the composition of semen. Prostate & seminal vesicles secrete seminal fluid = 10% sperm (50-150 million per ml) & 90% glandular secretions SV = fructose, prostaglandins, proteins that facilitate clotting PG = zinc, citric acid, antibiotic-like molecules, enzymes

Function of glands pH 7.5 is best for sperm – from bulbourethral to neutralize residual urine Fructose – energy from seminal vesicles Prostaglandins – chemicals that cause uterine contractions (sv)

Take good care! http://www.youtube.com/watch?v=iR5aUPAa2ak