Cardiac Flashcards
Where does the heart sit?
in the mediastinum which is the area between the lungs
Superior
base
inferior
apex
what is the function of the azygous vain?
carries blood from walls of upper abdomen and upper lower back back to heart.
drain tissue between the lungs
What is the heart enclosed in?
sac called the pericardium
what are the 3 layers of the heart?
– Epicardium- External membrane
• visceral pericardium
– Endocardium- endothelium
– Myocardium- cardiac muscle
what does a septum separate?
separates the right and left sides
of the heart, this is called the atrial and
ventricular septum
What do valves separate?
separate the atria from the ventricle
Right A-V valve
tricuspid
Left A-V valve
bicuspid
pulmonary valve
opening into Pulmonary
artery
aortic valve
opening into the aorta
What are the four chamber of the heart?
– Right Atrium
– Left Atrium
– Right Ventricle
– Left Ventricle
right and left atria
— two superior, posterior
chambers
— receive blood returning to
heart
right and left ventricles
— two inferior chambers
— pump blood into arteries
Pulmonary circuit
Pumps venous (deoxygenated) blood to the
lungs
Systemic circuit
Pumps (oxygenated) blood to the rest of the
body
pulmonary artery
Artery that carries “VENOUS” (deoxygenated)
blood
pulmonary vein
Vein that carries “ARTERIAL” (oxygenated)
blood
does cardiac muscle require aerobic respiration?
Yes,Because of this, the heart does not fatigue
easily. Downside is, the heart is very
sensitive to limitation of the oxygen supply
Where does the heart get its metabolic blood supply from?
The left and right coronary arteries, which
are the first branches off the aorta as it
leaves the heart.
• Compromise of this blood flow is called
coronary artery disease (CAD)
What is Ischemia?
Not enough Oxygen being delivered to the
tissue.
What is the result of ischemia?
If prolonged, the oxygen starved tissue dies
(necrosis or infarction)
Is ischemia reversible?
Ischemia is reversible, necrosis
(infarction) is not
What is the cardiac conduction system?
cardiac conduction system is a path of
myocytes that are auto-rhythmic and
conduct action potentials.
what is an action potential?
a wave of depolarization
What 3 waves are produced during the cardiac cycle?
P wave, QRS complex and T wave
P Wave
caused by atrial depolarization
QRS Complex
caused by ventricular depolarization
T Wave
results from ventricular repolarization
what is systole?
ventricular contraction
what is diastole?
ventricular relaxation
What is normal sinus rhythm?
set by SA node at 60 – 100 bpm
•adult at rest is 70 to 80 bpm (vagal inhibition)
What is arrhythmia?
abnormal cardiac rhythm, anything that is
not NSR
what is tachycardia?
resting adult HR above 100
•stress, anxiety, drugs, heart disease or rise body temp.
what is bradycardia?
resting adult HR < 60
•in sleep and endurance trained athletes
What is an infants HR?
120 bpm or more
what is pulse?
surge of pressure in artery
do positive chronotropic agents raise or lower HR?
raise HR
do negative chronotropic agents raise or lower HR?
lower HR
cardiac center of medulla oblongota
an autonomic control center with two neuronal pools:
a cardioacceleratory center (sympathetic), and a
cardioinhibitory center (parasympathetic)
Cardioacceleratory center
stimulates sympathetic cardiac nerves to SA node, AV
node and myocardium
what does norepinephrine bind to?
-adrenergic receptors in the heart (positive
chronotropic effect)
Cardioinhibitory center
stimulates vagus nerves
what does the left vagus nerve secrete?
secretes ACH (acetylcholine) which binds to
muscarinic receptors
vagal tone
background firing rate holds HR
to sinus rhythm of 70 to 80 bpm
what is the lubb-dubb sound called?
auscultation
when does the Lubb sound occur?
S1 = closing of AV valves
When does the Dubb sound occur?
S2= closing of aortic and pulmonic
valves, and reopening of AV valves
what is the period between S1 and S2 is called?
Systole (higher BP)- ventricular ejection
What is the amount of blood ejected called?
stroke volume
what is normal stroke volume?
70mL
The interval from S2 to the next S1 is called?
– Diastole (lower BP)- ventricular filling
what is cardiac output?
Amount ejected by ventricle in 1 minute
cardiac output equation
Heart Rate x Stroke Volume
what is normal cardiac output?
about 4 to 6L/min at rest
what is world class athlete cardiac output?
35 L/min
what is cardiac reserve
difference between a persons
maximum and resting CO
raises with fitness decreases with disease
what is the frank starling law of the heart?
The greater amount of blood volume returning to the
heart (preload) during diastole (the relaxed phase) the
greater the amount of blood volume ejected out of the
heart (stroke volume) during the systolic(contraction phase).
True or false:stretch increases force of
contraction
true
what are the three factors governing stroke volume?
1.Preload (venous return)
2.Contractility (force of heart muscle)
3.Afterload (resistance from blood
pressure)
ex. increased preload or contractility causes higher stroke volume
increased afterload causes decreases stroke volume
what is preload?
Amount of tension in ventricular myocardium
before it contracts (venous return parallels
preload)
increased preload causes increased force of contraction
what is ejection fraction?
The percentage of the blood leaving the ventricle
versus the percentage staying
ejection fraction equation
Ejection frac. = Stroke Volume / EDV (70/120= .58)
what is normal resting heart?
60%
what is normal active heart?
90%
what are some positive inotropic agents?
— hypercalcemia, catecholamines,
glucagon, digitalis
what are some negative inotropic agents?
— hyperkalemia, hypocalcemia
what is inotropy?
Contraction force for a given preload
preload is the _____ of cardiac output
ally
afterload is the _____ of cardiac output
enemy
what is normal HR?
70
what is normal SV?
70
what is normal CO?
70x70 or 4,900 mL
true or false?Things that increase cardiac output,
increase cardiac work
true
Pulmonary edema-
Left side failure
fluid accumulates in pulmonary tissue
Systemic edema:
Right sided Failure
fluid accumulates in systemic tissue
