Cardiac Output
Factors that contribute to the regulation of heart rate
Autonomic Nervous System and Hormones released by the adrenal medullae.
Three Factors that Regulate SV
1. Preload - ° of stretch before contraction. 2. Contractility- forcefulness of contraction 3. After load - pressure before ejection of blood from ventricles
Typical Total Blood Volume
5 L
Cardiac reserve
Difference between a person's maximum cardiac Output and cardiac Output at rest.
Cardiac Output
Volume of blood ejected from the left ventricle (or the right ventricle) into the aorta (or pulmonary trunk) each minute.
Positive Inotropic Agents
substances that increase contractility
Preload is proportional to
the EDV (end diastolic volume)
Afterload
the pressure that must be overcome before a semilunar valve can open
Two Key factors that determine EDV
1. Duration of ventricular diastole 2. Venous return- volume of blood returning to the right ventricle.
What makes your heart rate go faster during physical activity?
Proprioceptors that send nerve impulses.
Preload
Strech that increases the force of contraction (like rubber band) the greater blood flow in diastole : greater in systole
Contractility
Strength of contraction at any given preload
Cardiac Output Equation
Stroke Volume (SV in mL/beat) * Heart Rate (HR in beats/min)
What are the receptors that monitor the stretching of major arteries and veins?
baroreceptors
What are the receptors that monitor chemical changes in the blood?
chemoreceptors
What are some conditions that can increase afterload?
hypertension and artherosclerosis
Where in the brain is the HR regulated?
in the cardiovascular center in the medulla oblongata
The Frank-Starling law of the heart
keeps the same volume of blood flowing in both the systemic and pulmonary circulations
Congestive Heart Failure
loss of pumping efficiency by the heart
