19.6 Regulation of Cardiac Output Flashcards
cardioacceleratory center
cardiac center in the medulla oblongata that communicates with the heart by way of right and left cardiac nerves carrying sympathetic postganglionic nerve fibers
cardioinhibitory center
cardiac center in the medulla oblongata that communicates with the heart by way of the right and left vagus nerves carrying sympathetic preganglionic nerve fibers
cardiac plexus
a web of mixed sympathetic and parasympathetic fibers tucked in between the aortic arch, pulmonary trunk, and lower trachea
cardiac output
the amount of blood ejected by each ventricle per minute
cardiac reserve
the difference between the maximum and resting cardiac output
tachycardia
a persistent, resting adult heart rate of above 100 bpm
bradycardia
a persistent, resting adult heart rate below 60 bpm
positive chronotropic agents
factors outside of the heart itself that raise the heart rate
negative chronotropic agents
factors outside of the heart itself that lower the heart rate
vagal tone
the steady background firing rate of the vagus nerves that holds the heart rate down to its usual 70 to 80 bpm at rest
proprioceptor
A sensory receptor of the muscles, tendons, and joint capsules that detects muscle contractions and joint movements.
baroreceptor
A cardiovascular pressure sensor that triggers autonomic reflexes in response to fluctuations in blood pressure; baroreceptors are located in the heart, aortic arch, and carotid sinuses.
chemoreceptor
An organ or cell specialized to detect chemicals, as in the carotid bodies and taste buds.
beta blockers
drugs that inhibit the binding of catecholamines to the beta-adrenergic receptors and slow down the heart
hyperkalemia
potassium excess that keeps the membrane voltage elevated, inhibiting cardiomyocyte repolarization
