Learning objectives
Upon completion of this chapter, you should be able to:
1.
Label a diagram of the heart, including all chambers, valves, great vessels, coronary vessels and the conduction
system.
2.
Describe the flow of blood during the cardiac cycle, including flow to the cardiac muscle.
3.
Outline the conduction system of the heart, correlating the normal ECG pattern with the underlying electrical
activity in the heart.
4.
Discuss four normal controls of blood pressure.
5.
Describe the capillary fluid shift, including factors that influence the movement of fluid in clinical situations.
Introduction to the
cardiovascular system
Glossary of key terms
actin:
thin filament, a component of a sarcomere or muscle unit
arrhythmia:
a disruption in cardiac rate or rhythm
arteries:
vessels that take blood away from the heart; muscular, resistance vessels
atrium:
top chamber of the heart, receives blood from veins
auricle:
appendage on the atria of the heart, holds blood to be pumped out with atrial contraction
automaticity:
property of heart cells to generate an action potential without an external stimulus
capacitance system:
the venous system; distensible, flexible veins that are capable of holding large amounts of blood
capillary:
small vessel made up of loosely connected endothelial cells that connect arteries to veins
cardiac cycle:
a period of cardiac muscle relaxation (diastole) followed by a period of contraction (systole) in the heart
conductivity:
property of heart cells to rapidly conduct an action potential of electrical impulse
diastole:
resting phase of the heart; blood is returned to the heart during this phase
dysrhythmia:
a disruption in cardiac rate or rhythm, also called an arrhythmia
ectopic focus:
a shift in the pacemaker of the heart from the sinoatrial node to some other site
electrocardiogram (ECG):
an electrical tracing reflecting the conduction of an electrical impulse through the heart muscle; does not
reflect mechanical activity
myocardium:
the muscle of the heart
myosin:
thick filament with projections, a component of a sarcomere or muscle unit
oncotic pressure:
the pulling pressure of the plasma proteins, responsible for returning fluid to the vascular system at the capillary
level
pulse pressure:
the systolic blood pressure minus the diastolic blood pressure; reflects the filling pressure of the coronary arteries
resistance system:
the arteries; the muscles of the arteries provide resistance to the flow of blood, leading to control of blood pressure
sarcomere:
functional unit of a muscle cell, composed of actin and myosin molecules arranged in layers to give the unit a striped or
striated appearance
sinoatrial (SA) node:
the normal pacemaker of the heart; composed of primitive cells that constantly generate an action potential
Starling’s law of the heart:
addresses the contractile properties of the heart; the more the muscle is stretched, the stronger it will
react, until it is stretched to a point at which it will not react at all
syncytia:
intertwining networks of muscle fibres that make up the atria and the ventricles of the heart; allow for a coordinated
pumping contraction
systole:
contracting phase of the heart, during which blood is pumped out of the heart
Test your current knowledge of the cardiovascular system with a PrepU Practice Quiz!
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