Mammalian Cardiovascular System

Cardiac Output = Stroke Volume x Heart Rate
CO = SV x HR ~ 5 liters/min (at rest)
CO = (EDV - ESV) x HR

where End-diastolic Volume (EDV), End - systolic Volume (ESV)

Pressure-Volume Loop

Determinants of Cardiac Performance Preload (initial stretch) Afterload Contractility Heart rate
	Figure 14-26 from Rhoades and Pflanzer.

Intrinsic Regulation of Stroke Volume (SV):

• Huxley’s Sliding Filament theory
• Frank Starling Relationship (Starling’s Law)
• The greater the volume of blood in the ventricle, the greater the contraction.

Extrinsic Regulation of Stroke Volume (SV):

• Sympathetic stimulation or circulating catecholamines
  • increase contractility, decrease ESV.
    
    
• Parasympathetic stimulation
  • decrease contractility, increase ESV.

Extrinsic Regulation of HR

• Sympathetic innervention (norepinephrine) increases the rate of depolarization, increases HR.
• Parasympathetic innervention (acetylcholine) decreases rate of depolarization, decreases HR.
• Adrenal gland (catecholamines), increases HR.
• Thyroid gland (thyroid hormone), increases HR.

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