A Ring of Smooth Muscle, the Ureteral Sphincter, Surrounds the Ureters

question 44

True/False

A ring of smooth muscle, the ureteral sphincter, surrounds the ureters where they enter the urinary bladder.

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Definitions:

Circadian Rhythms

The natural, internal processes that regulate the sleep-wake cycle and repeat roughly every 24 hours.

Pineal Gland

The pineal gland is a small endocrine gland in the brain that produces melatonin, a hormone that regulates sleep-wake cycles.

Melatonin

Melatonin is a hormone produced by the pineal gland that regulates sleep-wake cycles and is often used as a supplement to treat sleep disorders.

Hypothalamus

A small region of the brain that plays a crucial role in many important functions, including releasing hormones, regulating body temperature, and controlling hunger and thirst.