EXAM 2 Cardiac System Flashcards
You expect that your patients aortic valve is calcified, therefore non compliant. what sign might you expect to find when you auscultate the heart?
Murmer
in which phase of the cardiac contraction is the cardiac muscle perfused
diastole
5 stages of cardiac cycle
- atrial systole (ventricular diastole)
- isometric ventricular contraction
- ventricular ejection (isotonic)
- isometric ventricular relaxation
- atrial systole (ventricular diastole
systole
contract/ejecting blood
diastole
relaxed/receiving blood
what phase of the cardiac cycle is the pulse we feel?
ventricular ejection
phase of cardiac cycle when blood leaves atria and enters into ventricles, ventricles contract
isometric ventricular contraction
semilunar valves
aortic and pulmonic valves
Firm, thick valves between ventricles and pulmonary artery and aorta
Aortic and pulmonic valves (semilunar valves)
valves that are tricuspid
Aortic and pulmonic valves (semilunar valves)
what is competence?
Prevention of back flow into ventricles
Thin, flexible valves between atria and ventricles
Tricuspid and mitral valves (atrioventricular or AV valves)
mitral has how many leaflets?
2
chordae tendinea are attached to_____.
papillary muscles
dense connective tissue cords from valves to papillary muscles
chordae tendinea
these Prevent AV valve leaflets from bulging excessively into atria during ventricular contraction
chordae tendinea
these muscles contract during ventricular
systole and maintain tension throughout systole
Papillary muscles
what does competency depend on?
coordinated function of the annulus, valve leaflets,
papillary muscles, and ventricular walls
narrowed valve due to thickening, calcification, non-separation of leaflets
Stenosis
what is stenosis?
narrowed valve due to thickening, calcification, non-separation of leaflets
leaky valve due to stretching, stenosis, papillary muscle or cordae tendinae disruption
Regurgitation
what is Regurgitation
leaky valve due to stretching, stenosis, papillary muscle or cordae tendinae disruption
what is Valvular “atresia”?
the absence of valve formation (no connection between chambers)
stretching of annulus effects?
competency
disorder where leaflets gets pushed up into atria and allows back flow, pt will feel this and think it palpitations
mitral valve prolapse
sound that is low “lub” as the AV valves close at the start of ventricular systole
S1
sound that is a high-pitched “dup” as the semilunar valves close after ventricular systole
S2
pulse we see in jugular vein correlates with what sound?
s1
pulse we feel correlates with what sound?
S2
sound when 2 av valves close at same time
S1
sound when ventricular valves close
S2
Sometimes the interval between aortic and pulmonary valve closure during inspiration is not simultaneous, causing two sounds to be heard, what is that sound?
split s2
sound that happens if 2 semilunar valves close at different times
split S2
sound that may be heard one third of the way through diastole in many normal young individuals (rapid ventricular) (“Ken-tuc ky”), or indicate disease (e.g., heart failure or volume overload)
third sound (S3)
sound may be heard immediately before S1 when atrial pressure is high or the ventricle is stiff (ventricular filling) (“Ten nes-see”) (e.g., LV hypertrophy or heart failure)
fourth sound (S4)
sound that occurs after diastole, can be normal or associated with disease (heart failure )
S3
Sound caused by blood as it enters from atrium crashing into ventricular wall
S3
Sound heard before S1
S4
sound that is blood turbulence around valves
murmer
sound that is blood turbulence around blood vessels
bruits
sounds caused by blood turbulence in the heart, most commonly around valves (late aortic stenosis)
Murmurs
sounds caused by blood turbulence in blood vessels (carotid bruit)
Bruits
what encloses the heart and separates it from thoracic viscera
Pericardium
Two layers of Pericardium
Visceral: thin inner layer, directly attached to the myocardium
Parietal: tough, fibrous out layer
Space between the visceral and parietal pericardium (the pericardial sac) contains 5 to 30 mL of clear______.
pericardial fluid
purpose of pericardial fluid
Lubricates to minimize friction
thin inner layer of pericardium, directly attached to the myocardium
Visceral
tough, fibrous out layer of pericardium
parietal
what is cardiac tamponade caused by?
too much pericardial fluid, can be caused by stabbing,HIV, etc.
when pericardial fluid is low and can hear during heart sound in coordination with breathing
friction rub
Three major epicardial arteries (outside heart)
Right coronary artery
left coronary artery divides into:
Left circumflex artery
Left anterior descending (LAD) artery
artery that Supplies the apex, left anterior wall, anterior septum
Left anterior descending (LAD) artery
artery that Supplies the lateral left
Left circumflex artery
artery that Supplies the right wall, posterior wall, posterior septum
Right coronary artery
Smaller branches that extend from the coronary arteries, penetrating into and perfusing the myocardium
intramural arteries
one blocked coronary artery can lead to__.
hypoxia of the heart,
this can cause angina
When the left ventricle contracts, what valve opens?
aortic
what prevents filling of the coronary arteries.
The valve cusps
When this happens, the aortic pressure closes the aortic valve, allowing the coronary arteries to fill.
left ventricle relaxes
artery associated with widow maker
left common coronary artery
what Side of heart provides most perfusion?
left
hypoxia to heart will cause the pt to have ____.
pain
Blood from heart muscle is drained by the cardiac veins into the ________,
coronary sinus
Blood from heart muscle is drained by the cardiac veins into the coronary sinus, then into the ____.
right atrium
relationship of coronary veins and coronary arteries?
Coronary veins tend to parallel coronary arteries
The heart is fully developed by pregnancy week___.
7 – 8
In utero function of ductus arteriosis and foramen ovale is to ______.
reduce blood flow to lungs
when does the ductus arteriosis closes off completely
Within a few days after birth
when the ductus arteriosis closes off completely, it forms the ___.
ligimentum arteriosum
if the ductus arteriosis DOES NOT close off completely, what is this called?
patent ductus arteriosis
Foramen ovale is located between?
atria
when does Foramen ovale (between atria) close?
at birth
Foramen ovale (between atria) closes at birth and gradually fuses together over _____.
several weeks or months
electrically conductive cells which discharge rhythmically, starting an electrical impulse which travels through conductive pathways from myocyte to myocyte
pacemakers
Sinoatrial node (SA node; “pacemaker”) beats how many per minute?
60-100 beats/minute
Atrioventricular node (AV node) beats how many per minute?
40-60 beats/minute
where is SA node located?
upper lateral portion of right atrium
where is av node located?
between atria and ventricles
role of av node
let electrical signals pass through but regulates speed
Internodal atrial pathways is sending signals along ___.
cardiac muscle cells to cardiac muscle cells, myocyte to myocyte conduction is slow, you see this in bundle branch block.
these are present in the atria or ventricles
and can take over when the SA and AV nodes aren’t
functioning or conduction from them is blocked
“Latent pacemakers”
Action Potential in the SA and AV nodes are due to what movements across plasma membranes?
Na+, Ca++, and K+
Parasympathetic (acetylcholine) stimulation causes what to action potential?
hyperpolarizes and decreases rate of firing
this stimulation causes hyperpolarization and decreases rate of firing to action potential
Parasympathetic (acetylcholine) stimulation
Sympathetic (epinephrine) stimulation causes what to action potential?
speeds depolarization and increases discharge rate
this stimulation speeds depolarization and increases discharge rate to action potential
Sympathetic (epinephrine) stimulation
Pacemaker firing rate is
influenced by _______.
temperature
higher temperature will do what to firing rate?
increase it
node that sets pace
SA
Internodal pathways conduct to what node
AV
AV node delays transmission to _____.
bundle of His
cardiac conduction
Bundle of His to bundle branches to Purkinje fibers to ____.
myocytes
depolarization of atrial muscle is ____.
atrial systole
a measure of electrical activity in the heart.
electrocardiogram
account for 90% myocardial volume
Cardiac muscle cells (myocytes)
what secretes atrial natriuretic peptide (ANP) with atrial distension (stretch)
Atrial myocytes
ANP causes _____.
vasodilation, diuresis (loss of water through urine) and Na+ excretion
what produce B-type natriuetic peptide (BNP) with ventricular distention (similar effects to ANP)
Ventricular myocytes
atrial stretch causes secretion in ____.
ANP
ventricular distention causes secretion in ____.
BNP
Provide strong union between cardiomyocyte fibers maintaining cell-to-cell cohesion
Intercalated disks
Provides low-resistance bridges for the spread of excitation from one cell to another
Intercalated disks
The heart has 3 things associated with cardiac metabolism
An abundant blood supply providing O2 and nutrients
High myoglobin content (muscle O2 “storage” protein)
Many mitochondria (fat metabolism, requires more O2)
Myocytes derive most of their energy from ____.
aerobic metabolism- requires continuous supply of O2
Energy sources for heart
Glucose (35%)
Ketones and amino acids (5%)
Fat (60%)
preferred substrate for heart
fat
Frank-Starling Law
The pressure developed in the ventricle is proportional to the ventricular end-diastolic volume
according to the Frank-Starling Law increased stretch results in ______.
increased contractile force, resulting in increased stroke volume
cardiac rate x stroke volume =
cardiac output
nerve that provides all parasympathetic control for heart
vagus nerve
effects of vagus nerve on heart
Decreases HR by decreasing SA and AV node pacing
vagus nerve does not affect ____.
myocardial contractility
Sympathetic nervous system effects to cardiac control
Increase HR via increasing SA and AV node pacing
Increase in myocardial contractility and stroke volume
for cardiac control, the Sympathetic nervous system Nerves arise from spinal what segments? (thoracic vertebra)
T2-T4
the spinal nerves for sympathetic control, Pass into the cardiac plexus to the_______.
SA node (right) and AV node (left)
what slows down repolarization in cardiomyocyte conduction?
calcium
At rest, the inside of the cardiomyocyte is_______ compared to outside the cell (+20 mV).
negatively charged (-90 mM)
cardiomyocyte conduction steps
- Rapid depolarization (phase 0) due to Na+ influx
- Initial rapid repolarization (phase 1) due to inactivation of Na+ channels and activation of repolarization process (phase 3) due to net K+ efflux through K+ channels
- Plateau (phase 2) due to Ca2+ influx through more slowly opening Ca2+ channels (the Ca2+ current, ICa)
- Rapid repolarization process (phase 3) due to closure of Ca2+ channels with continued K+ efflux through K+ channels
- Return to the resting membrane potential (phase 4)
