Chapter 20 Part 3 Flashcards
amount pumped by each ventricle in 1 minute
cardiac output
HR=
number of beats per minute
volume of blood pumped out by 1 ventricle with each beat. correlates with force of ventricular contraction
stroke volume
hr x sv=
co
entire blood supply passes through each side of the heat ``
1x/min
what side is pulmonary congestion on
left
left sided heart failure=
pulmonary congestion
in pulmonary congestion what side is fully functioning
right, but left has inadequate ejection
blood vessels in lungs fill with blood, pressure increases and fluid leaks from BV into lung tissue->
pulmonary edema-> suffocation
right sided heart failure=
peripheral congestion
blood is stagnant in peripheral congestion which means
fluids pool in tissue spaces and body impaired to obtain adequate nutrients and O2/ remove wastes. swelling in extremities
failure of 1 side= strain on other side->
complete heart failure
how do you treat congestion
diuretics, decrease BP, digitalis, heart transplant
if sudden drop in BV or heart weak->
SV drops and CO maintained via increase in HR and contractility
temporary stressors influence
HR via homeostatic mechanisms: neural, chemical and physical
factors that increase HR=
+ chronotropic factors
neg vice versa
normal hr
60-100
tachycardia
> 100 due to stress, elevated temp, drugs
bradycardia
<60 due to low temp, drugs or PNS. May warn of brain edema after head trauma
most important extrinsic control affecting HR
ans
emotional or physical stressord activates
SNS
whats is released at cardiac synapses
Ne
ans binds to beta 1 adrenergic receptors in heart which means
threshold reaches quicker
SA node fires more rapidly and heart
beats faster
secreted by adrenal medulla
epi
what increases bmr, large quantities increase in hr
direct heart action, also enhances epi and ne effect
thyroxine
hypocalcemia increase or decrease hr
decrease
hypercalcemia increase or decrease hr
increase
xs elevation=
life threatening arrythmia
hyperkalemia depolarizes
RMP and lead to heart block and cardiac arrest
hypokalemia life threatening also causing
arrhythmia
other factirs on hr
age
gender
exercise
body temp
fetus hr
140-160
females hr
72-82
males hr
64-72
irregular heart rhythm, due to intrinsic conduction system defects
arrythmia
arrythmia causes
uncoordinated atrial and ventricular contractions
arrythmia causes fibrillation=
rapid and irregular vs out of sync contractions where sa node control is disrupted by rapid activity in other parts of the heart
squirming bag of worms. useless as a pump
fibrillation
electrical shock- disruption of twitching by depolarizinf entire myocardium
defibrillation
constant monitoring of heart rhythms and slows an abnormally fast hr or shock given when heart fibrillates
implantable cardioverter defribrillators
prolonged coronary blockage=
ischemia>20 min
in myocardial infarction cardiac tissue dies so
amitotic so tissue is replaced with noncontractile scar tissue
symtoms of MI
chest pain radiates to left shoulder, arm, and jaw , SOB, N/V and diaphoretic
most comon cause of mi
thrombus formation in coronary artery
angioplasty
surgery with small balloon in femoral artery to coronary artery, inflated, flattem deposits. stent inserted to keep open
coronary bypass
surgery relieves effects of obstruction, uses radial artery, saphenous vein, internal mammary artery
tPA=
BREAKS DOWN CLOTS
