Human cells contain 23 pairs of chromosomes for a total of 46. There are 22 pairs of autosomes and one pair of sex chromosomes. The sex chromosomes are the X chromosome and the Y chromosome.Sex Chromosomes: In human sexual reproduction, two distinct gametes fuse to form a zygote.f an X sperm cell fertilizes an egg, the resulting zygote will be XX or female. If a sperm cell containing no sex chromosome fertilizes an egg, the resulting zygote will be XO or male. Sex Chromosomes Z-W: Birds, insects like butterflies, frogs and some species of fish have a different system for determining gender.
It is the abnormal leaking of blood backwards from the left ventricle, through the mitral valve, into the left atrium, when the left ventricle contracts, i.e. there is regurgitation of blood back into the left atrium. MI is the most common form of valvular heart disease.t is the abnormal leaking of blood backwards from the left ventricle, through the mitral valve, into the left atrium, when the left ventricle contracts, i.e. there is regurgitation of blood back into the left atrium. MI is the most common form of valvular heart disease.
The earliest sign of a leaking mitral valve is normally a heart murmur. This is produced by the turbulence created when some of the blood goes backward through the leaking mitral valve into the left atrium.Dogs may develop a murmur from a leaking mitral valve as early as four to six years of age.he earliest sign of a leaking mitral valve is normally a heart murmur. This is produced by the turbulence created when some of the blood goes backward through the leaking mitral valve into the left atrium.