Chapter 24, Problem 5WWTS

Summary Introduction

Introduction:

Calcium (Ca) regulates skeletal strength, muscle contraction, blood clotting, acts as a second messenger, and promotes neurotransmitter exocytosis. Low calcium concentration is maintained in the intracellular location because more concentration of phosphates is required for cellular processes. High concentration of Ca and phosphate leads to calcium phosphate crystal formation in the cytoplasm of the cell. Hence, cells pump out calcium ions to the extracellular location to maintain high concentration phosphate ions.

The concentration of phosphate ions is relatively higher in ICF (intracellular fluid) than ECF (extracellular fluid). Phosphate ions are the important components of ATP, GTP, nucleic acids, and cAMP. Hydrolysis of these compounds can generate more phosphates in the ICF. ATP-associated cellular processes depend on phosphates. Phosphate ions activate several metabolic pathways by the process of phosphorylation, where enzymes and substrates are phosphorylated. Also, phosphate ions serve as buffers to stabilize the body pH.