The sensory receptor involved in detecting blood pressure is the mechano receptor. Mechano receptors are a type of sensory receptor that respond to mechanical stimuli, such as pressure or vibration. In the case of blood pressure, mechano receptors located in the walls of blood vessels are responsible for detecting changes in pressure. These receptors are specifically called baroreceptors. When blood pressure increases, the baroreceptors in the arterial walls detect the increased stretch and send signals to the brain to regulate and maintain blood pressure within a normal range. This feedback loop helps to ensure that the organs and tissues of the body receive an adequate blood supply. Therefore, option 2 is the correct answer.