How High Planes Fly. Planes equipped with jet engines fly at greater altitudes than propeller-driven aircraft. These include commercial flights, cargo jets and even private passenger jets. The air traffic control tower usually assigns a cruising altitude of up to 39,000 feet, but long flights are typically assigned higher altitudes. By keeping these planes at assigned altitudes, air traffic control creates invisible stacked highways in the sky, keeping enough air space between the flights.
Blockage to or damage in the fallopian tube is one of the causes of infertility. Fallopian tubes play an important role in ovulation, as well as conception. Once the female egg is released from the ovary, one of the fallopian tubes (i.e. the fimbriae) picks up the egg and pushes it to pass through the tube.
Inside the fallopian tube, tiny cilia push the egg toward the uterus. To continue, the sperm must surge against this motion to reach the egg. Some sperm get trapped in the cilia and die. During this part of the journey, chemicals in the reproductive tract cause the membranes covering the heads of the sperm to change.ome sperm remain behind, caught in the folds of the cervix, but they may later continue the journey as a backup to the first group. Inside the uterus, muscular uterine contractions assist the sperm on their journey toward the egg.