Brain natriuretic peptide (BNP), also known as B-type natriuretic peptide, is a hormone secreted by cardiomyocytes in the heart ventricles in response to stretching caused by increased ventricular blood volume. BNP is named as such because it was originally identified in extracts of pig brain.
How your bladder works. Your bladder is controlled by a complex system of nerves from your autonomic nervous system (parasympathetic and sympathetic), as well as by your spinal nervesare nerves that enter and exit the spinal cord, transmitting sensory and motor information to and from the brain.
Sympathetic stimulation of the adrenergic receptors causes the contraction of the radial muscle and subsequent dilation of the pupil. Conversely, parasympathetic stimulation causes contraction of the circular muscle and constriction of the pupil. The mechanism of mydriasis depends on the agent being used.