Chapter 24, Problem 3WWTS

Summary Introduction

Introduction:

The concentration of potassium ions (K⁺) is high in the intracellular fluid (ICF). It determines the volume and intracellular osmolarity of the cell. It regulates resting membrane potential and depolarization of nervous and muscular systems with sodium. It serves as a cofactor for translation and is involved in other metabolic processes. Homeostasis of K⁺ is linked with sodium. Nearly 90% of K⁺ ions are filtered through the glomerulus and they are reabsorbed by the proximal convoluted tubule (PCT). The rest of the K⁺ ions are excreted through the urine. Later, nephron controls the variations in the K⁺ ion excretion; distal convoluted tubules and collecting duct (CD) return the amount of K⁺ ions to the tubular fluid. When K⁺ concentration is more, high amount of K ions is released by tubules. If the K⁺ concentration is low, low amount of K⁺ ions is secreted by the tubules.