final chp. 20 Flashcards
4 chambers of the heart
right & left atrium; right & left ventricle
they deliver equal volumes of blood through the pulmonary and systemic system
pericardium structures
- visceral pericardium (inner layer)
- parietal pericardium (outer layer & inner layer of pericardial sac)
cardiac tamponade
excess pericardial fluid
auricle
extension of atrium
heart wall layers
epicardium : covers the heart (visceral pericardium)
myocardium : cardiac muscle tissue
endocardium : inner epithelial layer
atrioventricular valves
folds of fibrous tissue that connect atria to ventricles, permit blood flow in one direction
superior vena cava
returns blood from head, neck, chest and upper limbs
inferior vena cava
returns blood from trunk, viscera and lower limbs
coronary sinus
delivers blood from cardiac veins to the right atrium
moderator band
connects interventricular septum to papillary muscles
pulmonary semilunar valve
regulates blood flow from pulmonary trunk into ventricle
right atrioventricular valve
tricuspid valve
pulmonary veins
deliver oxygenated blood to the left atrium
bicuspid valve
mitral valve, allow blood to flow into the left ventricle
aortic semilunar valve
lets blood travel from the ventricle to the ascending aorta, to the aortic arch into the descending aorta
left and right coronary arteries
vessels with the highest blood pressure
elastic rebound
blood entering the aorta stretches the vessel but when the ventricle relaxes the aorta recoils and pushes blood to the systemic circuit
right coronary artery
supplies blood to right atrium, ventricles and conduction system
left coronary artery
supplies blood to left atrium, left ventricle and interventricular septum
great cardiac vein
all veins empty into here
runs along anterior surface of ventricles
drain blood from region supplied by interventricular artery
empties into coronary sinus
small cardiac vein
drains posterior surface of right atrium and ventricle
conducting system
generates and distributes electrical impulses necessary to push blood through systemic and pulmonary systems
components of conduction system
SA node, AV node, internodal pathways, AV bundle, purkinje fibers
SA node
found in right atrium wall
creates 80-100 action potentials per min
depolarizes to establish heart rate
AV node
found near coronary sinus
impulse from SA node travels by internodal pathways to AV node
allows atria to contract before ventricle due to 100 msec delay
purkinje fibers
distribute impulses to ventricular myocardium
AV bundle
fibers that the impulse travels along
pacemaker action potential
occurs in the SA and AV node
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cardiodynamics
the movement and force generated by cardiac contractions
ESV: end systolic volume
blood remaining in ventricles after ventricular systole
EDV: end diastolic volume
blood remaining in ventricles after ventricular diastole
SV: stroke volume
amount of blood pumped out of ventricles in one beat, results in ESV
stroke volume calculation
EDV - ESV
cardiac output
HR x SV
amount of blood pumped out the left ventricle in 1 min
cardioacceleratory center
increases HR, controls sympathetic neurons
- results in reduced repolarization and more rapid depolarization
- opens Na+ and Ca2+ channels
cardioinhibitory center
slows HR, controls parasympathetic neurons
- opens K+ channels
- results in hyperpolarization
the cardiac cycle part 1
- atrial contraction (systole) AV valves open and blood goes into the ventricles
- atrial relaxation (diastole) AV and semilunar valves are closed, EDV in ventricles
- ventricular contraction (systole) and build pressure in closed AV valves
the cardiac cycle part 2
- pressure built up causes the the opening of semilunar valves and blood ejection from ventricles
- ventricular relaxation (diastole) when pressure drops and blood flow forces all heart valves closed. blood then flows into the atria
- ventricular diastole: all heart chambers relax and valves are closed, as the atria fills this builds pressure in the ventricle and ventricles fill passively
