basics Flashcards
which ventricle occupies most of the anterior surface
right ventricle
comes out of the right ventricle and
bifurcates into its left and right branches and heads into the lungs
pulmonary artery
comes out of the left ventricle, ascends to the level of the sternal angle, and then arches up and over the pulmonary arteries and then descends into the thorax
aorta
dump their blood collected deoxygenated blood into the right atrium
superior and inferior vena cava
dump oxygenated blood return from the lungs into the left atrium
pulmonary veins
sac around the heart
pericardium
inner lining
endocardium
heart muscle
myocardium
outer surface
epicardium
myocardium has what
intercalated disks with gap junctions = speed!
❖ Right atrium, near the
insertion of the SVC
❖ Inherent rhythm 60-100
bpm)
❖ Usually sets the heart
rate (sinus rhythm)
❖ Initiates Depolarization
Wave
SA node
❖ Anterior
❖ Middle (Wenckebach
branch)
❖ Posterior
internal pathways
Anterior Inter-Atrial band or Bachmann’s bundle
interatrial pathways
❖ Located at the base of the
right atria near the
interventricular septum
❖ Smaller cells, fewer gap
junctions = Slower
❖ Maximal rate is 40-60 bpm;
also maximal ventricular rate
AV node
❖ Only cellular connection between atria and ventricles
❖ Together AV node and AV bundle make up the AV junctional tissue
❖ If SA node fails, AV junctional tissue can control heart rate
❖ Intrinsic heart rate of 40-60 bpm
❖ Slows down the cardiac impulse
❖ Impulse is delayed before conducting down the bundle of His and its branches to depolarize the ventricles.
AV junction or bundle of HIS
left anterior bundle branch; thinner,
carries impulses to septum, left
anterior wall, and anterior papillary
muscle
left anterior fascicle
. post. bundle branch; thicker, carries impulses to posterior, inferior, left ventricular free wall and posterior papillary m. with dual blood supply, less likely to become
ischemic
left posterior fascicle
travel down towards the apex of the heart where they fan out into Purkinje fibers
both left and right BB
❖ Electrical Stimulus pass through
the ventricular myocardium
❖ If both the SA and AV node fail,
The purkinje fibers can generate and electoral signal
❖ the intrinsic rate for
the purkinje system is about
20 to 40 bpm
❖ Muscular Contraction starts at
the apex and circumferential
❖ Fast rate of action potential
generation, numerous sodium
ion channels and mitochondria
and fewer myofibrils
purkinje fibers
depolarization wave spreads upward from
apex
atrium squeezing
P wave
ventricle squeeze
QRS complex
heart restarts to do it all over again
T wave
normal conduction
sinus rhythm
time for blood to leave atrium and fill ventricle
delay in AV node
abnormal conduction
atrial arrhythmias
junctional rhythm
ventricular rhythm
rate at which electricity is conducted
cardiac conductivity
rate at which electricity is conducted at internodal pathways
fast
rate at which electricity is conducted at SA node
slow
rate at which electricity is conducted at AV node
SLOW
rate at which electricity is conducted at right and left bundle branches
fast!
rate at which electricity is conducted at purkinje fibers
FASTER!!
ability to spontaneously generate an impulse (depolarize)
cardiac automaticity
primary pacemaker
SA node
outside of the sinus node pacemaker (non-sinus)
ectopic
blockage of stimuli through AV junction
AV heart block
disease of bundle branches
bundle branch block
damage to ventricular muscle
ST segment changes
1 killer of all Americans, plaque and fat inside plumbing
coronary artery disease
Supply the anterior septum, the
anterior wall, and in most cases apex.
9 o’clock to 1 o’clock
LAD
Supply the lateral wall
2 o’clock to 4 o’clock
LCX
Supply the posterior lateral segments, the inferior segments, and the posterior septum.
5 o’clock to 8 o’clock
RCA
what bproduces the sound of the heartbeat
As the heart valves close, the heart sounds of S1 and S2 arise from the vibrations emanating from the leaflets and the blood flow they “SHUT DOWN”. They SNAP CLOSED producing a noise
Closure of the Mitral valve and Tricuspid valve (end of diastole, beginning of systole)
S1
Closure of the Aortic valve and Pulmonic valve (end of systole)
S2
pathologic (BAD) sounds found in diastole
S3 and S4
atrioventricular valves (AV)
Because they separate the atrium and ventricles
The Tricuspid valve and Mitral valve
3 leaflets (Mercedes Benz)
aortic and pulmonic valves
❖ Venous Side
❖ Responsible for pulmonary Circulation:
❖ circulation to the lungs and pulmonary vasculature
❖ LOW PRESSURE SYSTEM
right side of heart
❖ Arterial Side
❖ Responsible for Systemic Circulation
❖ circulation to the most distal portions of
the body
❖ HIGH PRESSURE SYSTEM
left side of heart
(EDV-ESV)
stroke volume
volume of blood ejected with a single beat from the ventricle.
stroke volume
CO/HR
stroke volume
stroke volume normal
60-100mL/beat
the volume of blood ejected from each ventricle over 1 minute
❖ HR x SV
❖ Dependent on Preload, Contractility, and Afterload
cardiac output
the ability of the cardiac muscle (and cell/myocyte), when given a load (volume of blood that stretches the muscle), to shorten. = THE SQUEEZE POWER.
Increased by: sympathetic stimulation
Decreased by: ischemia (hypoperfusion) to the myocardium
myocardial contractility
The volume of blood (the load that puts stretch pressure) that is present in the Ventricle at the end of diastole = HOW MUCH IS THE VENTRICLE BEING STRETCHED?
Increased by: increased venous return, inspiration, increased
intravascular volume
Decreased by: exhalation, decreased LV output, pooling of blood in the capillary bed or venous system
preload
There is an optimal length between sarcomeres (stretch) at which the tension in the muscle fiber is greatest resulting is the greatest force of contraction.
frank starling law
the degree of vascular resistance to ventricular contraction.
Or… the force of resistance that the ventricle must overcome to
empty its contents at the beginning of systole.
Increased by: increased arterial vascular tone, increased aortic
volume, Aortic/Pulmonic valve stenosis, increased PVR
afterload
The ability of the aorta/large arteries to distend (stretchiness)
distensibility
esistance in the
circulatory system to the flow of blood.
Some resistance is required to create a blood pressure
Particularly at the arteriole level
Poiseuille’s Law:
peripheral vascular resistance
