BIOMOLECULES AND ENZYMES

Detailed explanation-1: -If calcium decreases, the parathyroid glands sense the decrease and secrete more parathyroid hormone. The parathyroid hormone stimulates calcium release from the bones and increases the calcium uptake into the bloodstream from the collecting tubules in the kidneys.

Detailed explanation-2: -If the calcium in your blood decreases below homeostasis levels, a gland in the brain will sense the decrease and send a chemical message to your bones. Your bones will release calcium into the blood, bringing blood calcium levels back up.

Detailed explanation-3: -Answer and Explanation: The regulation of blood calcium levels is an example of negative feedback. The parathyroid gland secretes the parathyroid hormone (PTH).

Detailed explanation-4: -A negative feedback loop regulates the levels of PTH, with rising blood calcium levels inhibiting further release of PTH. Parathyroid hormone increases blood calcium levels when they drop too low. Conversely, calcitonin, which is released from the thyroid gland, decreases blood calcium levels when they become too high.

Detailed explanation-5: -Positive feedback occurs to increase the change or output: the result of a reaction is amplified to make it occur more quickly. Negative feedback occurs to reduce the change or output: the result of a reaction is reduced to bring the system back to a stable state.