Chapter 9 Flashcards
Blood vessels
Passageways through which blood is distributed from heart to all parts of the body and back to the heart.
Heart
Serves as a pump that establishes the pressure gradient needed for blood to flow to tissues.
Blood
Transport medium within which materials being transported are dissolved and suspended
Pulmonary circulation
Closed loop of vessels carrying blood between heart and lungs
Systemic circulation
Circuit of vessels carrying blood between heart and other body parts.
Atrioventricular valves
Right and left AV valves positioned between atrium and ventricle on right and left sides.
Prevent backflip of blood from ventricles into atria during ventricular emptying.
Right AV valve
Tricuspid valve
Left AV valve
Bicuspid/mitral valve
Chordae tendinae
Fibrous cords which prevent valves from being everted. Papillary muscles
Semilunar valves
Aortic and pulmonary valves.
Lie at juncture where major arteries leave ventricles.
Prevented from everting by anatomic structure and positioning of cusps.
Endothelium
Thin inner tissue.
Epithelial tissue, lines entire circulatory system.
Myocardium
Middle layer, cardiac muscle.
Constitutes bulk of heart wall.
Epicardium
Thin external layer which covers heart.
Cardiac muscle fibers
Interconnected by intercalated discs and form functional syncytia.
2 kinds of membrane junctions: desmosomes
Gap junctions
Autorhythmicity
Heart beats via
Contractile cells
99% of cardiac muscle cells
Do mechanical work of pumping
Normally don’t initiate action potentials
Autorhythmic cells
Do not contract
Specialized for initiating and conducting action potentials responsible for contraction of working cells.
Myocardial aps
RMP of -90mV
Depolarized to threshhold by APs originating in SA node.
Systole
Contraction heart phase
Diastole
Relaxation phase of the heart
End-diastolic volume
Volume of blood in ventricles at end of diastole
Stroke volume
Amount of blood ejected from ventricles during systole
End-systolic volume
Amount of blood left in ventricles at end of systole
Parasympathetic stimulation
Slows heart rate
Sympathetic stimulation
Speeds heart rate up
