The objective of this work is to develop a model of the continuous arterial pressure signal provided by the arterial catheter, and to validate it against real data. The model involves a number of novel features not encountered in previous models of this form, namely terms to describe the arterial valve closing, the respiratory variations of blood pressure and heart frequency, and the dicrotic notch.. The focus of this project is to develop a simple mathematical model capable of describing the well-known blood pressure signal. The model will be verified by comparison with real data.