This work is the outcome of my Ph.D. at H.N.B.Garhwal University,Srinagar,Uttarakhand,India. The work is divided into seven chapters included first chapter having Introductory parts,having definitions of mathematical terms,second chapter is the study of mathematical study of Micro circulation using plasma release-cell layering technology,and Model of blood flow in porous walls, third chapter is study of mathematical approach to fluctuation in human respiration. Chapter four is the mathematical modeling of microbial growth.Chapter five,six and seven deal with mathematical modeling of personality and psycho-dynamics.