Pneumococcal infections are caused by Streptococcus pneumoniae, a gram-positive, catalase-negative organism commonly referred to as pneumococcus.
Blood pressure is a measure of the changing fluid pressure within the circulatory system. It varies. from a peak pressure produced by contraction of the left ventricle, to a low pressure, which is. maintained by closure of the aortic valve and elastic recoil of the arterial system. The peak.
Blood pressure is influenced by cardiac output, total peripheral resistance and arterial stiffness and varies depending on situation, emotional state, activity, and relative health/disease states. In the short term it is regulated by baroreceptors which act via the brain to influence nervous and endocrine systems.