Flashcards in heart Deck (32):
discuss the cardiac cycle?
the route that a drop of blood takes throughout the heart.
1. vena cava-r. atrium-av valve-r. ventricle-pulmonary semilunar valve-pulmonary circulation
2. pulmonary veins-L. atrium-mitral valve-l. ventricule-aortic semilunar valve- aorta- body tissues.
how the heart cells unique from other tissues?
have the ability to automatically depolarize.
heart can work on its own
all parts of the heart operate in coordinated motion to move blood.
what is the 2 most important functions of the heart?
2. functional syncyctium
name the intrinsic conduction system?
1. SA node
2. intermodal pathway
3. av node
4. av bundle +bundle branches
5. pukinje fibers
what is the pacemaker of the heart?
what iniates contraction of the atrium?
the internodal pathway
what is the role of the av node
delay electrical info. so ventricles can fill
what sends electrical signals to the bottom of the heart?
av bundle (send to apex)
what stimulates the ventricle cardiac muscles to contract (contractor)
what is polarization?
what ends mix (mixing of charges) . the trigger for actions to occur
where do you see membrane potential?
in excitory cells. create a difference of charge in cells.
why can the heart self pace itself?
because of the leaky sodium channels. it can operate outside the nerve influence.
name 3 general rules of intrinsic conduction system?
1. if cells are excited, they immediated excite adjacent cells
2. after cells are excited, it requires little amount of time to reset its membranes and cannot be excited during this period (refractory period)
3. if cells are not excited by neighbor, it will spontaneously depolarize but it may take longer for this to occur on its own based on the location of the cell.
what builds up when 02 not present?
one are of heart is irritated. ex: a. flutter (becomes pacemaker of heart)
ectopic foci (plural)
multiple areas of heart are irritates ex. v. fib
amount of blood pump out by each ventricle in one minute. (meet oxygen and nutrient needs of body)
formula for cardiac output?
CO= HRX SV
measure of the amount of blood per stroke/contraction of the heart.
what controls the heart to beat below 100/min?
parasysmpathetic nervous system
HR above 100/min cause?
sysmpathetic nervous system.
amount of blood in ventricle prior to contractor (how much venous blood return to ventricles
frank starling law
more you stretch heart, more harder it contracts
force with which cardiac muscles contract
pressure heart must overcome to deliver blood to ex: aorta (overcome resistance)
how many % of americans died of cardiovascular disease?
hardening of arteries that inhibit blood flow (build up of plaque)
why is atherosclerosis bad?
in coronary arteries, it increases risk for ischemia and subesequent arrythmia