17, 18 Flashcards
(131 cards)
volume of blood that the heart pumps out per minute
stroke volume
stroke volume determined by three things
preload
afterload
contractility
the volume of blood returned to the right side of the heart
preload
the force that the heart has to overcome to eject blood into systemic circulation (think pressure)
afterload
preload, afterload and contractility all influence the cardiac output how
by affecting the stroke volume
% of blood that is ejected from the left ventricle during systole
normal %
ejection fraction
50-70%
what kinds of problems can occur with decreased ejection fraction; what would decrease ejection fraction
can cause a backup of blood into the pulmonary vessels
tissue perfusion diminishes
heart failure
problems with too much blood in ejection fraction
increase pressure in the pulmonary vessels can cause pulmonary edema
largest veins in the body; where do they empty blood
superior and inferior vena cave
right atrium
three layers of artery wall tissue
outer: tunica adventitia: ct
middle: tunica media: smooth muscle
inner: tunica intima: endothelial cells
the force that the blood exerts against the walls of the aorta and its branches
blood pressure
blood pressure greatest during what
ventricular contraction / systole, when blood is ejected into the aorta
if blood volume decreases, kidneys secrete what
renin enzyme into the blood
renin acts on certain proteins to produce
angiotensin 1
angiotensin I is converted to angiotensin II by
angiotensin-converting enzyme from lungs
angiotensin II acts directly on what
what is the outcome
What does angiotensin II stimulate
what does this cause
blood vessels
causing constriction and raising blood pressure
adrenal gland to release aldosterone
causing sodium and water retention by the renal tubules- increasing blood volume- increasing bp elevation and improved cardiac output
sympathetic nervous system’s role in regulating vessel diameter (releases what)
prompts release of norepinephrine and epinephrine that cause vasoconstriction
cardiovascular age-related changes:
what happens to the actual heart and the contractility; resulting in what
becomes stiffer and contractile ability decreases, resulting in decreased stroke volume
cardiovascular age-related changes:
coronary arteries, cardiac valves
ca: become tortuous and dilated, areas of calcification
cv: thicken, murmurs are common
cardiovascular age-related changes:
SA node
aorta
SA: loses about 40% of its pacemaker cells over time, predisposing to cardia dysrhythmia or SA node failure
aorta: stiffer, contributing to increase in bp due to left ventricle pumping against greater pressure
Cardiovascular disease:
includes what kind of issues
congenital or acquired, heart failure, stroke, hypertension, dysrhythmias, infection and inflammation, DM, metabolic syndrome, obesity, sedentary lifestyle, and stress
Cardiovascular disease:
causes
coarctation ( narrowing of the aorta)
arteriosclerosis (thickening and loss of elasticity)
atherosclerosis (buildup of plaque)
aneurysms
stenosis (inflammation of the valve structure causing narrowing)
insufficiency (incomplete closure) of heart valves
hypertrophy (thickening of myocardial muscle)
hypertension
pulmonary hypertension
valve problems
ischemia
infarct
endocarditis (inflammation within the lining and valves)
pericarditis ((inflammation of the surrounding sac)
Cardiovascular disease:
modifiable risk factors
obesity
high cholesterol
hypertension
diabetes
smoking
sedentary lifestyle
excessive stress
excessive alcohol
drug use
common diagnostic tests & purpose:
electrocardiography
holter monitor
loop recorder
exercise ECG stress test
chemical stress test
e: record impulses of the heart to determine rate, rhythm, site of pacemaker, and presence of injury at rest
h: correlates normal daily activity with electrical function of heart to determine whether activity causes abnormalities
l: continuously records ECG to determine if an arrhythmia is the cause of symptom (syncope, palpitations, or dizziness)
e: records electrical activity of the heart during exercise; insufficient blood flow and oxygen can be identified by the abnormal waveforms they produce
c: used for those who cannot exercise for an ECG stress test