congestive heart failure Flashcards
(128 cards)
Where is the only vein-capillary-vein system located in the body?
hypothalamus
what part of the body holds the most blood at any given time?
VEINS!
What are things that contribute to resistance of w/in yo body
1) blood viscosity (effected by volume and # of RBC)
2) total blood vessel length
3) blood vessel diameter
what is the biggest contributor to minute-to min control of resistance in the vascular system?
Blood vessel diameter
R= 1/(r^4)
can the heart heal itself?
yes, but very slowly- only 1% of heart muscle cells are replaced per year
how are electrical currents spread w/in the myocytes?
via gap junctions
what does atrial natriuretic peptide do?
regulates the concentration of sodium in the extracellular fluid
What part of the heart does the sympathetic fibers innervate?
the entire heart muscle, and node cells
releases NE
**the receptors will also bind to the neuroendocrine hormone epinephrine from the adrenal gland
what part of the heart does the pSNS innervate?
the SA-AV node, released acetylcholine
what is the inherent rate of the SA node?
100 bpm, but it is moderated by the nervous system
what part of the heart conduction system has a .1s delay>
the AV node- allows the atrai to contract and totally fill the ventricles
What to the purkinje fibers do?
supply the papillary muscles-tell them to contract before the rest of teh ventricles to hlep prevent backflow through the valves
why is the refractory period for heart cells important?
long refraction means the cell won’t fire again until its last contration is almost relaxed away- lets its empty completely
arrhythmia
uncoordinated atrial and ventricular contractions caused by a defect in the conduction system.
Fibrillation
: a rapid and irregular (usually out of phase) contraction where the SA node is no longer controlling heart rate.
ventricular fib
is more life threatening. The ventricles pump ineffectively and without filling. If the heart’s rhythm is not rapidly reestablished then circulation stops and brain death occurs
ectopic focus
abnomral pacemaker that takes over the conduction system- usually bc it goes faster than the SA node
Extrasystole
premature conractions, can be atrial or ventricular
total block
ventricles beat at their intrinsic rate- too slow to maintain circulation
partial block
AV impulse isslow, but it does get through
coronlary ostia
openings to coronary vessels- blood falls back into them during dicrhotic notch- heart is the FIRST THING to get oxygenated b/c of these
Cardiac Output
amount of blood pumpled out of each ventricle in one minute
CO=HR X SV
what is the normal cardiac output?
5.25 L/min
what is the most common way your body varies CO?
Via heart rate