parentage; heritage; origin

plot; storyline; scenario / previously-settled path forwards; scenario

to hijack a bus

pulse / vein / something that continues (in a straight line, path) / connection

branch (thin and long) / something stringy, thin and long state / path / reason / something written in bullet points (terms)

muscle tone

main point, thread (of a story)

muscle, tendon / vein, artery / reason, logic / plot, storyline / counter for long thin things; counter for roads or blocks when giving directions / lineage, descent

muscle / tendon / have an aptitude / vein / (usually in place names) road

gland