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26 Cards in this Set

  • Front
  • Back
Heart pumps blood into 2 circuits in sequence...
pulmonary circuit (to/from lungs); systemic circuit (to/from rest of the body)
Pericardial Cavity
surrounds the heart; lined by pericardium made of two layers (primary goal is to reduce friction)--visceral pericardium (covers heart surface) and parietal pericardium (lines pericardial sac that surrounds heart
Visceral pericardium
epicardium--covers heart surface
Parietal pericardium
lines pericardial sac that surrounds heart
outer portion of atrium
coronary sulcus
deep groove that marks boundary of atria and ventricles
posterior interventricular sulcus (theres an anterior as well)
mark boundary btwn left/right ventricles; sulci contain major cardiac blood vessels; filled w/protective fat
Cardiac Muscle Cells
Shorter than skeletal muscle fibers; have single nucleus; have striations (sarcomere organization); depend on aerobic metabolism; connected by intercalated discs
interatrial septum
separates atria
transmit tension
gap junctions
transmit action potential
interventricular septum
separates ventricles
atrioventricular valves
4--located btwn atrium and ventricle; ensure one-way flow from atrium to ventricle (left thicker than right which only goes to lungs)
Heartbeat needs two types of cardiac cells....
contractile cells--provide the pumping action; cells of the conducting system--generate and spread the action potential
the conducting system
initiates and spreads electrical impulses in heart (wave-like fashion); 2 types of cells (nodal and conducting); heart is self-exciting
Nodal cells
pacemaker cells; reach threshold first and set heart rate
conducting cells
distributes stimuli to myocardium
normal pacemaker is the
sinoatrial (SA) node
impulse spreads from SA node...
across atria, to atrioventricular (AV) node, to AV bundle and bundle branches, via purkinje fibers to ventricles
2 phases in cardiac cycle
systole--contraction phase; both ventricles simultaneously;;;diastole--relaxation phase
blood volume reflexes
stimulated by changes in venous return (VR is amt of blood entering heart); atrial reflex (speeds up heart rate and triggered by stretching wall of right atrium); frank-starling principle (increases ventricular output and triggered by stretching wall of ventricles
Parasympathetic innervention (ANS)
releases Ach (acetylcholine); lowers heart rate and stroke volume
Sympathetic innervation (ANS)
releases NE (norepinerephrine) and raises heart rate and stroke volume
Adrenal medulla hormones (ANS)
epinephrine, norepinephrine released; heart rate and stroke volume increased
other hormones that increase output.. (ANS)
thyroid hormones and glucagon
CNS control of the heart--basic control in medulla oblongata
cardioacceleratory center (activation of sympathetic neurons); cardioinhibitory center (governing parasympathetic neurons); higher centers; blood pressure sensors; oxygen, carbon dioxide sensors