Final answer:
Hypocalcemia is the condition characterized by excessive excitability of the nervous and muscular systems due to low blood calcium levels.
Step-by-step explanation:
Hypocalcemia, a condition characterized by abnormally low levels of calcium, is the condition characterized by excessive excitability of the nervous and muscular systems due to low blood calcium levels. In hypocalcemia, blood calcium levels are too low, which causes increased membrane permeability to sodium and results in muscle twitching, cramping, spasms, and convulsions. Severe deficits can paralyze muscles, including those involved in breathing, and can be fatal. Treatments vary according to the cause, but prognoses are generally good.