Three consonants carry one motion: something is thrown out. Throw it by hand (the plain verb), let it be thrown (the passive), or force it under the skin (inject, "throw in"). The same hurling idea names the injection itself and the fountain that throws water into the air. Watch how the causative binyan specializes a wide everyday verb into a precise medical act. Every word here is verified against pealim, niqqud included.
The same root runs through the verb system. Each binyan is a voice: it bends the one idea into active, passive, causative or reciprocal. Tap to hear.
Notice the split of labour: pa'al is the broad "throw", nif'al its passive "be thrown", and hif'il narrows to the technical "inject", the causative made it a specialist. The pi'el, pu'al, huf'al and hitpa'el slots are not lexicalized for this root.
Same root letters, different noun moulds (mishkalim). The mould tells you the function: who does it, the act of doing it, or the thing produced.
Strip the prefixes, suffixes and vowels. Three consonants remain, and the meaning lives there.