Heart rate persons with coronary artery disease. The heart rate is rhythmically generated by the sinoatrial node. It is also influenced by central factors through sympathetic and parasympathetic nerves. Nervous influence over the heartrate is centralized within the two paired cardiovascular centres of the medulla oblongata. The cardioaccelerator regions stimulate activity via sympathetic stimulation of the cardioaccelerator nerves, and the cardioinhibitory centers decrease heart activity via parasympathetic stimulation as one component of the vagus nerve. During rest, both centers provide slight stimulation to the heart, contributing to autonomic tone. This is a similar concept to tone in skeletal muscles. Normally, vagal stimulation
Brain heart infusion Haden. BHI typically contains infusion of beef or pig heart as well as calf brain, a source of amino acids (often either digested gelatin or other animal tissue), salt, disodium phosphate as a buffer, and glucose as a source of sugar. Many formulations for BHI agar also exist, in which agar is added as a gelling agent for growing plates of microorganisms. Brain heart infusion Brain heart infusion (BHI) is a growth medium for growing microorganisms. It is a nutrient-rich medium, and can therefore be used to culture a variety of fastidious organisms. In particular, it has been used to