Man (man here means mankind)  is composed of parts. He has a body and a soul. His body is composed of different organs or members. His soul, since it is a spiritual being, has no parts in the proper sense of the word; but it has different powers - the intellect, the will and the passions of his sense appetite.

The soul cannot be seen but its existence is known from its acts. Acts of the soul are reasoning, thinking and willing, and these acts are high above the power of flesh and bone. The soul is like to God because it is a spirit and will never die, and has understanding and free will. When we refer to being made in the image and likeness of God, it is mainly the soul that this reference is made to. "Let us make man to our image and likeness" (Gen, 1:26).

Man's soul is not material, (cannot be seen or touched), but was created to give life to a human body. When a soul leaves the body, death follows, for a body cannot live without the soul. The soul then, is the essence or animating  (living) principle of man.

Men do die. But men do not totally die. "It is appointed for men to die once, and after that comes judgment (Heb, 9:27). There is no "reincarnation or a second chance. What we call death is not a complete ceasing to be. Rather, it is a transition to another state of living. Nevertheless, death is a great enemy that men naturally fear and hate. Though his spiritual principle survives death and can be with the Lord, it is not good for man to lose that flesh which is part of himself. Man's immortality is not merely that of the soul but also that of the body in eternal life in the resurrection, when "death is swallowed up in victory" (Cor. 15:54).  At the end of time, the body will be reunited with the soul, as it was meant to be in the beginning.

The Soul Is Eternal. Each man is like God in being destined to live forever. This is one reason why every human person, however young or old, however useless or limited in terms of worldly possibilities is to be treated with great reverence. The soul is the noblest part of us, our true self. It cannot cease to exist. We cannot utterly destroy ourselves. The person who commits suicide transfers himself from one state of existence to another. The human soul is indestructible. This is the reason why abortion is so evil, as God creates the soul at the very instance of conception, and thus there is a real living person waiting to be born.

The soul separated at death, still remains the same being as it was while united to the body. St. Thomas Aquinas said: "There is no interruption in the substantial being of man." Whether in heaven, hell or purgatory, your identity is maintained with a continuity of memory and consciousness.

How long Does The Soul Live? Eternity is such a long existence, contemplating it is almost impossible. An existence which is infinite, with no end, and is independent of time or the things that are perishable. Clocks ticking away, minutes and hours and calendars making days, months and years belong to the perishable world - a world that is passing. Billions of years are as seconds of time compared to the endlessness of eternity. Or as the psalmist says, "A thousand years in Your sight are as yesterday!" (Ps. 90)

Your soul is immortal. It cannot die, and at the end of time, when trumpet sounds, your body will join your soul to participate in your eternal destiny, be it heaven or hell. Purgatory will be no more!

This is the splendid wonder of heaven - it never ends. Likewise, it is the miserable tragedy of hell.

Source: Mary, help of Christians magazine.

365  The unity of the soul and body is so profound that one has to consider the soul to be the "form" of the body; i.e., it is because of its spiritual soul that the body made of matter becomes a living human body; spirit and matter, in man, are not two natures united, but rather their union forms a single nature.

366  The Church teaches that every spiritual soul is created immediately by God - it is not "produced" by the parents - and also that it is immortal: it does not perish when it separates from the body at death, and it will be reunited with the body at the final Resurrection.

Catechism of the Catholic Church.