Heart and Vessels Flashcards
ather/o
fatty substance
arter/o, arteri/o
artery
atri/o
atrium
cardi/o
heart
coron/o
heart
pericardi/o
pericardium
rhytm/o
rhythm
sphygm/o
pulse
steth/o
chest
vas/o
vessel
vascul/o
vessel
ven/o, ven/i
vein
ventricul/o
ventricle
pericardial sac (parietal pericardium)
anchors heart to great vessels (aorta and venae cavae)
epicardium (visceral pericardium)
serous membrane covering heart’s surface
secretes pericardial fluid
myocardium
heart’s middle layer composed of cardiac muscle tissue
endocardium
heart’s inner most layer, lines the 4 chambers of the heart
coronary sulcus
marks separation of atria from ventricles
interventricular sulcus
mark separation of left and right ventricles
interatrial septum
separates two atria from each other
interventricular septum
separate ventricles from one another
pulmonary circuit
heart pumping blood to the lungs and back
CO2 is unloaded and O2 is loaded
systemic circuit
once blood is returned from lungs, left side of heart pumps blood to all parts of body to be returned back to heart
O2 is unloaded and CO2 is loaded
Steps of cardiac conduction system
- heartbeat started by SA node
- from SA node, cardiac muscle cells carry electrical impulse across myocardium of both atria causing depolarization
- while step 2 happens, other cardiac cells cary impulse to AV node
- AV bundle carries impulse down interventricular septum to apex
- Purkinje fibers fan out from AV bundle stimulating cardiac muscle cells to depolarize and contract
Phases of cardiac cycle
- Atrial systole: SA node fires, atria depolarize and contract together. increased pressure pushes blood through AV valves to ventricles
- Atrial diastole: atria repolarize and relax. pressure in superior/inferior venae cavae and pulmonary veins is greater than atrial pressure so blood rushes in
- Ventricular systole: once impulse is carried from AV node to purkinje fibers ventricles depolarize and contract together. chordae tendinae also contract to prevent backflow. contraction of ventricles decreases volume and increases pressure inside ventricles. blood pushed through pulmonary and aortic valves.
- Ventricular diastole: ventricles repolarize and relax. blood moves from AV valves to ventricles from atria. all 4 chambers fill with blood during this phase. atria are not contracting during this phase. blood is passively moving from atria to ventricles due to difference in pressure
sinus rythm
normal pace, with 70-80 bpm
vagal tone
a pace normally kept in check by autonomic nervous system through vagus nerve
ectopic focus
occurs when any part of conduction system other than SA node sets pace
nodal rhythm
occurs if AV node is ectopic focus