Blood calcium must be tightly regulated to prevent health problems. In the case of low blood calcium, chemoreceptive cells within the parathyroid glands detect the drop in Ca2+. This signals the synthesis of the hormone calcitriol. Calcitriol enters the blood, and encourages the uptake of calcium along the intestine, inhibits the loss of calcium in the urine, and encourages osteoclasts to resorb bone and release calcium into the blood, leading to a return to homeostasis.   What structure is the control center? 

Blood and interstitial fluid are water-based: many reactions occur within these fluids or use water molecules from these fluids to break chemical bonds. Which of the following properties of water does this best describe?

Extra credit: List all three forms of passive transport, and all three forms of active transport.

Which hormone is primarily involved in regulating the body’s circadian rhythms?

In the process of sound transduction, where does the conversion of sound waves into electrical signals primarily occur?

Extra Credit: Explain the role of the endolymph of the semicircular canals in activating the receptors during motion.

What is the primary function of aldosterone?

The release of which hormone is stimulated by low blood calcium levels?

Destroying the nerve cell axons in the infundibulum would result in the loss of which one of the following hormones?

Which type of photoreceptor is responsible for color vision?