Ka
kꜣWhat it is
The vital essence, created at birth on Khnum's potter's wheel alongside the body, and the thing whose presence makes a body alive.
What it needs after death
Food and drink, indefinitely. Every offering formula on every tomb wall is addressed to the ka rather than to the person, and mortuary endowments existed to keep the supply running for generations.
What “soul” loses
That death is described as going to one's ka rather than losing it. The ka does not depart; the body does.
The other parts
Ba
bꜣThe mobile, individual part: personality and the capacity to act, shown as a human-headed bird.
Akh
ꜣḫWhat a person becomes if everything works: ba and ka successfully reunited after death, transfigured...
Ren
rnThe name, treated as a real component of a person rather than a label attached to one.
Sheut
šwtThe shadow, understood as a real part of a person and as something with its own presence and protect...
Ib
jbThe heart: the seat of thought, memory, will and character, and the organ that testifies at the judg...