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.
Mitral valve syndrome is the term for the condition experienced by the small number of people who have symptomatic MVP. Symptoms, which in some cases may be related to leaking of the mitral valve, can include: 1  Chest pain (not caused by coronary artery disease or a heart attack). 2  Dizziness. 3  Fatigue. 4  Sensation of feeling the heart beat (palpitations). 5  Shortness of breath with activity or when lying flat (orthopnea).