Final answer:
The standard tourniquet in today's blood collection is an elastic band, which is different from a sphygmomanometer used for measuring blood pressure.
Step-by-step explanation:
The standard tourniquet used in today's blood collection is typically an elastic band that is applied to the upper arm or other limb to temporarily constrict venous blood flow. This makes the veins beneath the tourniquet become more prominent, which facilitates easier insertion of a needle for blood collection. While a tourniquet is primarily used in this manner during phlebotomy procedures, other devices such as a sphygmomanometer (blood pressure cuff attached to a measuring device) and a stethoscope are used for measuring blood pressure, as illustrated in the provided figures. The sphygmomanometer typically consists of an inflatable cuff, a valved rubber bulb to inflate the cuff, and a diaphragm gauge to measure the cuff's pressure. These are distinct from the tourniquet but are related in terms of their use in medical procedures involving the circulatory system.