A medical procedure used to open a blocked artery. Appeal An appeal is the action you can take if you disagree with a coverage or payment decision made by Medicare, your Medicare health plan, or your Medicare Prescription Drug Plan.
A uniflagellar sperm cell that is motile is referred to as a spermatozoon, whereas a non-motile sperm cell is referred to as a spermatium. Sperm cells cannot divide and have a limited life span, but after fusion with egg cells during fertilization, a new organism begins developing, starting as a totipotent zygote. The human sperm cell is haploid, so that its 23 chromosomes can join the 23 chromosomes of the female egg to form a diploid cell. In mammals, sperm develops in the testicles and is released from the penis.
Human diploid cells contain two sets of 23 chromosomes for a total of 46 chromosomes. When sex cells unite during fertilization, the haploid cells become a diploid cell. The production of sperm cells is known as spermatogenesis. This process occurs continuously and takes place within the male testes. Hundreds of millions of sperm must be released in order for fertilization to take place. The vast majority of sperm released never reach the ovum.