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 mitral valve (also known as the bicuspid valve or left atrioventricular valve) is a dual-flap (bi-from the Latin, meaning double, and mitral-from the Latin, meaning shaped like a mitre) valve in the heart that lies between the left atrium (LA) and the left ventricle (LV).uring diastole, a normally-functioning mitral valve opens as a result of increased pressure from the left atrium as it fills with blood (preloading). As atrial pressure increases above that of the left ventricle, the mitral valve opens. Opening facilitates the passive flow of blood into the left ventricle.