Why is knowing how many breaths someone takes essential? What is incentive spirometry?

Why does body temperature matter? How can hypothermia or hyperthermia affect the body? Is having a fever always a bad sign?

How is pulse different than blood pressure? What is an oximetre? How does a machine on your finger tell you so much about your health?

We have all heard 120/80, but what does that even mean? Where did blood pressure originate? What is a sphygmomanometer?