The ductuli efferentes possess cuboidal cells with microvilli and lysosomal granules that modify the ductal fluid by reabsorbing some fluid. Sertoli cells, which nurture and support developing spermatocytes, secrete a fluid into seminiferous tubules that helps transport sperm to the genital ducts. The bulbourethral glands secrete a clear secretion into the lumen of the urethra to lubricate it. The prostatic secretion, influenced by dihydrotestosterone, is a whitish (sometimes clear), thin fluid containing proteolytic enzymes, citric acid, acid phosphatase and lipids. The seminal vesicles produce a yellowish viscous fluid rich in fructose and other substances that makes up about 70% of human semen. Human Compositionĭuring the process of ejaculation, sperm passes through the ejaculatory ducts and mixes with fluids from the seminal vesicles, the prostate, and the bulbourethral glands to form the semen. In marsupial and placental mammals, copulation occurs through the vagina. In most vertebrates, including amphibians, reptiles, birds and monotreme mammals, copulation is achieved through the physical mating of the cloaca of the male and female. Internal fertilization takes place after insemination of a female by a male through copulation. Female fish, for example, spawn ova into their aquatic environment, where they are fertilized by the semen of the male fish.ĭuring internal fertilization, however, fertilization occurs inside the female's sexual organs. In external fertilization, the spermatozoa fertilize the ova directly, outside of the female's sexual organs. Cryoconservation of animal genetic resources is a practice that calls for the collection of genetic material in efforts for conservation of a particular breed.ĭepending on the species, spermatozoa can fertilize ova externally or internally. In animals, semen has been collected for cryoconservation. Semen is also a form of genetic material. The fluid is designed to be discharged deep into the vagina, so the spermatozoa can pass into the uterus and form a zygote with an egg. In humans, seminal fluid contains several components besides spermatozoa: proteolytic and other enzymes as well as fructose are elements of seminal fluid which promote the survival of spermatozoa, and provide a medium through which they can move or "swim". The process that results in the discharge of semen from the urethral orifice is called ejaculation. Semen is produced and originates from the seminal vesicle, which is located in the pelvis. It is secreted by the gonads (sexual glands) and other sexual organs of male or hermaphroditic animals and can fertilize the female ovum. Semen, also known as seminal fluid, is an organic bodily fluid created to contain spermatozoa. Subscribe here.Spermatozoa, in this case human, are a primary component in normal semen, and the agents of fertilization of female ova. Originally published in the September/October 2015 issue of World War II magazine. The elder Lewis gave the artifacts on these pages to Steven they went up for sale last April at New York’s Bonhams auction house, where the collection brought in $112,000, and offered a revealing look at one man’s war story.
“He would place items on the dining room table and then we would spend most of our day together discussing them in detail,” Lewis’s youngest son, Steven, recalled. Lewis, later a settled family man with five children, spent a lifetime reflecting on the mission.
Tibbets, selected Lewis to join him in a combat force-the 509th Composite Group-training in secret to use the bomber to deliver a weapon of unprecedented power. Another pilot in the B-29 program, Lieutenant Colonel Paul W.
Lewis had enlisted in the Army Air Corps early in the war electronics experience got him a gig testing weapons systems on a bomber under development, the B-29 Superfortress. In August 1945 the confident and rambunctious Lewis was 27, with sturdy, all-American good looks and a reputation as a skilled pilot and determined ladies’ man. Lewis wrote shortly after the B-29 he was copiloting, the Enola Gay, dropped an atomic bomb on Hiroshima. IF I LIVE A HUNDRED YEARS, I’ll never quite get these few minutes out of my mind,” Robert A. Enola Gay: Pilot's-eye View | HistoryNet Close