CV SYSTEM Flashcards
CV system delivers sufficient _______ to the tissues to meet metabolic demand.
Oxygen
CV transports metabolic waste products (carbon dioxide) from the _________ and delivery to the ________ for elimination
From the tissues
Delivery to lungs
CV system transports metabolic waste products to the kidneys for elimination. TRUE/FALSE.
TRUE
CV system supplies nutrients by absorption from ________ and delivers to the body
GI tract
How does the CVS regulate body temperature?
Vasodilation
Vasoconstriction
How does the CVS help to regulate cellular function?
Transport of hormones and other substances (NT, drugs etc)
The heart is an endocrine organ; what hormone does the heart secrete?
Natriuretic peptide
Sits directly posterior to the sternum, inbetween the lungs and anterior to the vertebral column; heart located here.
Mediastinum
From an anterior perspective, which side of the heart can be seen better?
RIGHT side
_______ side of the heart seen much better from a posterior perspective
Left
Great vessels are located also in the ________
Mediastinum
Brings venous deoxygenated blood from the upper part of the body to the right atrium
Superior vena cava
Brings deoxygenated venous blood from lower body to RA
IVC
Descending thoracic aorta runs along posterior aspect of heart and pierces the __________, then becomes the abdominal aorta.
Diaphragm
Esophagus and trachea also pass through the mediastinum. TRUE/FALSE
TRUE
The heart is surrounded by pericardial __________
Membranes
Most inner pericardial membrane
Visceral pericardium
Outer pericardial membrane
Parietal pericardium
Most inner pleural membrane; directly attached to the lungs
Visceral pleura
Outer most pleural membrane
Parietal pleura
Small band of tissue that separates the most outer pericardial and pleural membranes
Fibrous pericardium
Can have CV implications when we do this to pts, bc the layer between the heart/lungs is so thin
PPV
Branches right off aorta as emerges from LV, runs down coronary sulcus between RA and RV.
RCA
Left Main coronary artery Branches off of the aorta and quickly divides into what two coronary arteries?
Left anterior descending (LAD)
Left circumflex
Where is the LAD located on the heart?
In sulcus between LV and RV on anterior surface of heart
Pulmonary carries what type of blood?
Venous deoxygenated blood
Arteries carry blood to the heart. TRUE/FALSE.
FALSE
Arteries carry blood away from the heart
Veins carry blood to the heart. TRUE/FALSE
TRUE
Freshly oxygenated blood is returned to the heart after pulmonary circulation via ___________
Pulmonary veins
In most people the _______ becomes the posterior descending artery (PDA)
RCA
PDA descends posteriorly between what two structures of the heart?
RV and LV
In about _____% of people the PDA is a branch of the RCA
80%
In about 20% if people the PDA is a branch of what artery
Left circumflex
All coronary veins join together to form what vein?
Great Cardiac Vein
The great cardiac vein empties into the _______ that empties into the RA
Coronary Sinus
Tiny, microscopic veins that permeate walls of the heart and empty deoxygenated blood into all 4 chambers of the heart
Thebesian veins
Two reasons why PaO2 is less in the Left side of the heart than the blood at the pulmonary capillaries after gas exchange occurs.
Thebesian veins
Bronchial circulation (need blood but do not participate in gas exchange)
Two types of circulations in the lungs
Pulmonary (fresh blood back to LA)
Bronchial (tracheobronchial tree)
Outer most layer of the heart; directly attached and cannot be separated from the heart.
Visceral pericardium (epicardium)
Visceral pericardium composed of what?
Squamous epithelial cells
Loose connective tissue/fat
Thickest layer of the heart; muscle fibers.
Myocardium
What determines the thickness of the myocardium of the different chambers?
Workload on the heart
Order of chambers from largest myocardium to the least
LV
RV
LA
RA
Inner most layer of the heart, faces chambers in folds.
Trabeculae corneae
2 functions of the folds of the trabeculae corneae
Provides structure so when undergo contraction, do not collapse
Creates turbulence of blood flow; prevents blood clots
The visceral pericardium completely surrounds the heart, when it gets to the _________ it turns out on itself and becomes the parietal pericardium.
Great vessels
Space between visceral and parietal pericardium
Pericardial space (potential space)
Parietal and visceral pericardium combines are the ___________ pericardium; secretes fluid into pericardial space.
Serous pericardium
Under normal conditions there is ~______mL of fluid in the pericardial cavity
20mL
Purpose of pericardial fluid
Allows visceral/parietal pericardium to glide over smoothly during systole/diastole
Right outside the parietal pericardium and heaps anchor the heart in place and to adjacent structures
Fibrous pericardium
When pericardial membranes become inflamed; can be from infection, virus, etc.
Pericarditis
Classic auscultated sign of pericarditis
Friction rub
Pericarditis can be caused from something infectious or non-infectious. TRUE/FALSE
TRUE
Example of non-infectious cause of pericarditis
Nephrogenic toxins
Trauma to chest
Where is a friction rub best heard?
Apex of heart; 5th intercostal space midclavicular line
Increased capillary permeability in the pericardial membranes, allowing excess pericardial fluid to accumulate
Pericardial effusion
Pericardial effusion can lead to _________
Cardiac tamponade
Difference in pericardial effusion and cardiac tamponade
With cardiac tamponade, you will have CV manifestations
What usually is the determinant factor in whether a pericardial effusion/tamponade causes manifestations?
Length of time fluid is accumulated
The more quickly fluid accumulates, the more quickly can decompensate
How do we manage anesthesia with cardiac tamponade?
FULL, FAST, FORWARD
Keep them full, HR up, and blood moving forward
Pts with CT have a fixed _________ and cannot adjust their contractility; so CO is dependent on________ primarily. So you should avoid __________.
Fixed SV
CO dependent on HR
Avoid bradycardia
With CT, you want to avoid ________, because you take a risk of decreasing venous return and preload
Vasodilators
With CT, we need to optimize __________ to maximize LV filling
Volume status
With CT, maintain _________ tone, but do not overly constrict them.
Sympathetic
Why should we maintain spontaneous ventilation with CT?
PPV can result in CV collapse bc of decreased venous return
There are no valves between the IVC/SVC and the RA. TRUE/FALSE
TRUE
There should be constant flow of blood into RA, with a pressure gradient. What should the pressure gradient be between CVP and RA to allow this to happen?
CVP should be a little higher than pressure in the RA to allow blood to flow forward.
When RA pressure is greater than RV pressure, _________ opens and blood flows passively from RA to RV
Tricuspid leaflets
At some point the RA goes into systole and injects more blood into RV. TRUE/FALSE.
TRUE
When do the tricuspid leaflets close?
When RV pressure is > RA
RV goes into systole and chamber gets smaller, increasing RV pressure; when RV pressure is > pulmonary artery pressure, the ________ valve opens and blood ejected into pulm art circuit to lungs.
Pulmonary valve
“Heart strings”
Chordae tendineae
Chordae tendineae are attached to __________ muscles that are continuous with the myocardium
Papillary
During systole chordae tendineae are pulled tight and hold _______ in place. Preventing _________ bloodflow and favoring forward flow of blood into pulm circuit.
Tricuspid leaflets
Retrograde
Just like the vena cava, there are no _______ between the pulmonary veins and the LA.
Valves
When LA pressure is > LV pressure, then ________ leaflets open and there is initial passive blood flow into LV.
Mitral
When does mitral valve close
When LV pressure is > LA
LV goes into systole, and when LV pressure exceeds aortic pressure, then _________ valve opens to eject blood into aorta
Aortic
When does aortic valve close
When aortic pressure is > LV pressure
What opens and closes valve leaflets
Pressure Gradients
Which valves are associated with chordae tendineae and papillary muscles?
Atrioventricular valves
Tricuspid and mitral
Passive flow of blood from atrium to ventricle accounts for about ____% of ventricular preload.
~75%
When atria goes into systole, ~___% of blood is ejected into ventricle = atrial kick.
25%
What type of arrhythmia would cause atria to contract against closed atrioventricular valve, losing atrial kick.
Afib
What causes a transient increase in atrial pressure during ventricular systole?
Valve leaflets ballooning into the atrium
What causes heart sounds
Turbulence of bloodflow with opening and closing of valves
Location of pulmonic auscultatory area
2nd intercostal space, Left sternal border
How do you find the 2nd intercostal space?
Start at sternal notch, below notch is manubrium, bump where the manubrium meets the sternum is the angle of Louis; directly over should be 2nd intercostal space
Location of aortic auscultatory area
2nd intercostal space, Right sternal border
Location of tricuspid auscultatory area
5th intercostal space, Left sternal border
Location of mitral auscultatory area
5th intercostal space, L Midclavicular line
Why do we not auscultate to diagnose murmurs anymore?
Echocardiography/TEE
During ventricular diastole, what valves should be open?
Tricuspid
Mitral
If you hear a murmur during diastole at the tricuspid area, it would indicate what type of murmur?
Tricuspid stenosis
If you hear a murmur during diastole at the mitral area, it would indicate what type of murmur?
Mitral stenosis
If you hear a murmur during diastole at the aortic area, it would indicate what type of murmur?
Aortic regurgitation
If you hear a murmur during diastole at the pulmonic auscultatory area, it would indicate what type of murmur?
Pulmonic valve regurgitation
During systole, what valves should be open?
Aortic
Pulmonic
If you hear a murmur during systole at the aortic auscultatory area, it would indicate what type of murmur?
Aortic stenosis
If you hear a murmur during systole at the pulmonic auscultatory area, it would indicate what type of murmur?
Pulmonic stenosis
If you hear a murmur during systole at the tricuspid auscultatory area, it would indicate what type of murmur?
Tricuspid regurgitation
If you hear a murmur during systole at the mitral auscultatory area, it would indicate what type of murmur?
Mitral regurgitation
You can have combined diastolic systolic murmurs. How?
May be very stenotic when blood flowing through and valves may not shut completely either.
Why is it common for pts to have murmurs after an MI?
Bc papillary muscles or muscles attached to them can be infarcted and not function correctly anymore in keeping tricuspid/mitral valves shut during systole
The first organ to be perfused by the heart is the______
Heart
During the resting state, about ___% of CO circulates through the coronary arteries.
~3%
Driving force against blood flowing through the coronary arteries is what?
Pressure created by the LV during systole/contraction
Most perfusion of the heart occurs during ventricular systole. TRUE/FALSE
FALSE
Most perfusion occurs DIASTOLE
Why is perfusion of the heart hindered during systole?
Small arteries, arterioles, and capillaries are compressed during systole
Which chamber is it most important to have adequate diastole for perfusion?
LV
Sympathetic stimulation with epi/NE at alpha-1 receptors causes coronary artery ________
Constriction
Sympathetic stimulation with epi/NE at beta-2 receptors causes coronary artery ________
Dilation
During sympathetic stimulation, which receptor effect normally dominates?
Beta-2
Possible parasympathetic/vagal stimulation that affect coronary artery blood flow, via _______ receptors, usually minimal effect and mild _________.
Acetylcholine/muscarinic
Mild dilation
During the resting state, about _____% of O2 is extracted from coronary blood flow
~75%
Under normal conditions, in other areas of the body besides the heart, ~____% of O2 is extracted from the blood flow
~30%
The heart is very _______ hungry
Oxygen
Coronary arter blood flow and myocardial perfusion are controlled primarily by what?
Rate of myocardial O2 consumption
Any condition that increases myocardial O2 consumption causes reflex ________ of coronary arteries.
Dilation
If _______ on the heart increases, then O2 consumption increases.
Workload
For O2 supply to meet O2 demand, coronary arteries must __________ to increase blood flow and O2.
Dilate
What are some things that increase myocardial workload?
Increased strength of contraction
Increased afterload
Increased preload
Increased HR
What increases myocardial oxygen consumption and workload on the heart more than any other factor?
INCREASED HR
What would be of most benefit to a pt you were worried about perfusion of their CA?
Betablocker; decreased HR
What are some metabolic vasodilators; providing more bloodflow, more O2 delivery to tissues?
Increased CO2 Increased H+ ions Decreased pH Lactate Adenosine
What does it mean to be right coronary artery dominant?
PDA is a branch of the RCA
How is it determined whether you are right/left CA dominant?
By which CA your PDA branches off of
Regardless of dominance, the ___________ artery supplies the majority of blood flow to the heart in EVERYONE.
LEFT MAIN CA
Right atrium is perfused by what major artery?
RCA
Left atrium is perfused by what major artery?
Left circumflex
Right ventricle anterior is perfused by what major artery?
RCA
Right ventricle posteriorly is perfused by what major artery?
RCA (PDA)
LV (diaphragmatic/inferior) is perfused by what major artery?
Left circumflex and RCA(PDA)
LV anteriorly is perfused by what major artery?
LAD
Left circ
LV laterally is perfused by what major artery?
Left circ
Apex is perfused by what major artery?
LAD
Interventricular septum anteriorly is perfused by what major artery?
LAD
Interventricular septum posteriorly is perfused by what major artery?
RCA (PDA)
LV papillary muscles anteriorly is perfused by what major artery?
LAD
L circ
LV papillary muscles posteriorly is perfused by what major artery?
L circ and RCA (PDA)
SA node is perfused by what major artery?
RCA
Atrial internodal pathways are perfused by what major artery?
RCA
AV node is perfused by what major artery?
RCA
Bundle of HIS is perfused by what major artery?
RCA
Right bundle branch is perfused by what major artery?
LAD
Left bundle branch anteriorly and posteriorly is perfused by what major artery?
LAD
Leads V1-V4 are indicative of changes in what area of the heart?
Anterior surface
Leads V5-V6 are the best leads to see changes effecting what area of the heart?
Lateral surface of the heart
If you saw prominent Q waves in leads V1-V4, what coronary artery is most likely infarcted?
LAD
If ST elevation was present in V5-V6, what coronary artery is most likely infarcted?
Left circumflex
Two types of muscle
Striated and smooth
Two types of striated muscle
Skeletal
Cardiac
Muscle fibers in the atria and ventricles that bring about muscle contraction
Mechanical contractile fibers
Form electrical conduction system throughout the heart
Electrical fibers
Electrical fibers initiate and conduct __________ throughout the heart and to mechanical contractile fibers.
Action potentials
AP’s transferred to contractile fibers and are __________ with mechanical contraction
Coupled
This MUST precede mechanical contraction of the heart
Electrical impulses (AP)
Clinical scenario where we know there is not electrical/mechanical coupling.
PEA
Cardiac muscle is smooth muscle. TRUE/FALSE
FALSE
It is striated muscle
Actin:myosin ratio for cardiac muscle
2:1
Cardiac muscle includes tropmyosin and troponin (I,T, and C) similar to skeletal muscle fibers. TRUE/FALSE
TRUE
In cardiac muscle, actin is attached to _______ and forms sarcomeres.
Z-discs
What is actin attached to in smooth muscle
Dense bodies
Cardiac muscle contains intercalated discs and __________ between adjacent sarcolemma for spread of AP directly from muscle fiber to muscle fiber
Gap jxns
This allows for free flow of ions in cardiac muscle, and contraction as a unit.
Gap junctions
What are the 2 functional syncytium of the cardiac muscle?
Right and left Atria
Right and Left Ventricles
What’s the purpose of the functional syncytium?
When one muscle fiber becomes excited in either the right/left atria/ventricle, all of the fibers in the fxnal syncytium become excited and contract at the same time
The atria and ventricles are separated by fibrous tissue with openings for _________ and pathway for _________ fibers so impulse can be conducted, one way, from atria to ventricles
Valves
Electrical fibers
Heart requires flow of Ca+ into sarcoplasm from from what two sources?
Sarcoplasmic reticulum
EC fluid
The 2 sources of Ca+ allow for sustained contraction of cardiac muscles to enhance _______ and ______.
Stroke volume
Cardiac output
If you gave calcium to a pt having contraction issues, it would enhance their contraction bc the heart is affected by extracellular Ca+ concentrations. TRUE/FALSE.
TRUE
The inward movement of Ca+ from EC fluid and SR occurs during the cardiac ______
AP
Where one cardiac muscle fiber adjoins to the next one; forms gap jxn
Intercalated disks
Cardiac muscle fibers require a lot of this organelle because of a lot of consumption of O2 needed in the heart
Mitochondria
Cell membrane of cardiac muscle fiber
Sarcolemma
T tubule along with terminal cisterna on either side of it makes up what?
Triad
AP travels along sarcolemma and down the T tubule; opens up _________ channel where calcium enters from __________.
v-g Ca+ channel
EC fluid
Ca+ enters sarcoplasm and AP is transferred from T tubule to _________ , membrane is depolarizes, and v-g _____ channels are opened
Sarcoplasmic reticulum (on either side of t tubule)
V-g Ca channels
Both the Ca+ from the SR and EC fluid increases Ca+ sarcoplasmic conc, this pulls troponin ___ towards the Ca+, along with troponin ___ and ______.
troponin C towards Ca+
Troponin T and tropomyosin
When tropomyosin is pulled away, this uncovers the binding sites on ______ and allows for ________ to crossbridge and powerstroke
Uncovers binding sites on ACTIN
Allows for MYOSIN HEADS to CB and PS
Muscle fibers are arranged _______ around the ventricles to allow for a more effective SV and CO.
Obliquely
Vasopressors are frequently utilized for intraoperative hypotension in a radical neck dissection with free flap. TRUE/FALSE.
FALSE
You CANNOT use vasopressors for intraoperative hypotension in these cases
This can be used to verify adequate fluid volume status intraoperatively.
Pulse Pressure Variation
What would the benefits be of calcium administration for your patient with intraoperative hypotension?
Increased myocardial contractility
Calcium dependent exocytosis of NT (NE)
Sympathetic postganglionic neurons are depending on this for release of NE.
CALCIUM dependent exocytosis
3 properties of electrical fibers
Automaticity
Excitability
Conductivity
Property: Ability to automatically generate AP
Automaticity
Property: Becomes excited in response to AP’s
Excitability
Property: rapidly conducts AP’s
Conductivity
All electrical fibers have all 3 properties, BUT some fibers have more of one than the other properties. TRUE/FALSE.
TRUE
Located in the roof of the RA where the SVC joins with the RA.
SA node
SA node
<1cm
SA node primarily composed of ______ cells
Pacemaker cells (P cells)
Primary property of P cells.
Automaticity
Rate P cells generate AP
~60-100
AP generated by the SA node are transmitted through the superior, middle and inferior ____________ pathways
Atrial internodal pathways
Provides input to the LA from the SA node.
Interatrial branch of the atrial internodal pathway
Atrial internodal pathways and interatrial branch are composed of ______ cells.
Purkinje fibers
Primary property of purkinje cells is _______
Conductivity
We hope purkinje cells are lying adjacent to atrial muscle fibers to allow what?
Electrical mechanical coupling
2 atrial internodal pathways join back together to form the ________.
Atrioventricular node (AV node)
Where is the AV node located?
Bottom of the RA, right above the tricuspid valve
What type of cells compose the AV node
P cells T cells (transitional cells)
What are the 2 functions of the T cells in the AV node?
Slow the AP slightly so atria contract before the ventricles
Regulates # of AP’s that can get through
At what rate does the AV node generate AP in the absence of the SA node?
~40-60
Where the AV node enters and becomes the Bundle of HIS.
Superior part of interventricular septum
Bundle of HIS divides into what 3 bundle branches?
Right bundle branch
Anterior branch of Left bundle
Posterior branch of left bundle
Bundle branches terminate at ____________ that are hopefully adjacent to muscle fibers.
Purkinje fibers
Which two bundle branches descend into the interventricular septum towards the apex?
Right bundle branch
Anterior branch of Left bundle
Posterior branch of Left bundle innervates the _______ aspect of the LV.
Posterior
Bundle branch that innervates the purkinje fibers on the anterior and lateral LV
Anterior branch of Left bundle
Why does the left side of the heart have 2 bundle branches, and the right side have only one branch?
More muscle mass to depolarize on the L side.
Which ventricle contracts first?
RV
Less muscle mass to depolarize
AP from a large axon or skeletal muscle fiber has a RMP of ~ _____mV and a TP of ~ ____mV.
RMP ~ -85mV
TP ~ 60mV
In an AP of a large axon or skeletal muscle fiber, the depolarization/repolarization phase is SLOW/RAPID?
RAPID
Repolarization in cardiac AP is __________
Slow, prolonged
Why does the heart need slow, prolonged repolarization?
Allows for sustained AP and sustained contraction (CO and SV)
Cardiac AP takes about ________ msec.
~500msec
RMP for cardiac AP
~ -85mV
what are the 4 contributors to RMP at this time?
Potassium leak channels
Sodium leak channels
Na-K pump
(-) charged proteins that line cell membrane
If stimulus applied to cell membrane, causes initial influx of _____ ions and moves RMP upward in less negative fashion.
Sodium
At TP (~ ____ mV), there is opening of ___________ Channels and more influx of + charges into the cardiac cell
~ -60mV
V-g Na channels
Early Phase 0 of depolarization begins at -____mV and continues to about -____mV.
-90mV to ~ -40mV
What initiates early phase 0 of depolarization?
Initial stimulus causing initial Na influx
During early phase 0, cell membrane becomes impermeable to _______
Potassium
Early phase 0, -40mV, opening of v-g ________ channels.
Voltage gated Ca-Na channels
LATE phase 0 of depolarization begins at -___mV and continues to about +_______ mV.
-40mV - +20-30mV
Peak amplitude of depolarization in cardiac fiber is ~____mV
~ +20mV
At peak amplitude of depolarization, +20mV, the v-g ______ channels snap shut; ending __________ and beginning ____________.
At the same time, v-g _____ channels start to open up; initiating phase 1 of repolarization.
V-g Na channels shut
Ends depolarization
Begins repolarization
V-g K channels open
Phase 1 of repolarization begins at +_____mV and continues to _____ mV.
+20-30mV - 0mV
Longest phase of repolarization of cardiac muscle fiber.
Phase 2
Phase 2 of repolarization, the MP remains at about ______mV
0mV
Why does the MP remain at ~0mV during all of phase 2 of repolarization?
Equal influx/efflux of cations
Inward movement of Ca+ through slow Ca-Na channels; K channels are open = outward K+.
V-g Ca/Na channels shut at the end of phase ____ of repolarization; no more influx of + charges; beginning phase ____.
Phase 2
Begin phase 3
During phase 3, the only channels open for ion movement are?
K channels
During phase 3, K channels are fully open and MP SLOWLY/RAPIDLY returns to RMP.
Rapidly
The phase in between AP’s is phase ______; RMP.
Phase 4
Cell cannot depolarization again regardless of stimulus during this period
Absolute RP
ARP starts and ends at what phases of repolarization?
Starts Early phase 0, late phase 0, phase 1, 2 and most of 3.
Lasts until reaches TP in phase 3 (~60mV)
If an extra strong stimulus is applied, depolarization might occur in this period.
Relative refractory period RRP
RRP lasts from ~____mV down to ~_____mV.
-60mV down to ~ -85mV
Is depolarization happens during RRP, what abnormality might you see on the EKG?
QRS sitting right on top of the T wave
Only a mild stimulus applied can cause depolarization during this period
Supranormal refractory period. SNP.
SNP is form __mV to __mV.
~-85mV down to -90mV, RMP.
If depolarization occurs during SNP, what EKG change would you see?
QRS on downslope of T wave
In pacemaker cell AP’s, these channels are inactivated.
V-g Na channels
RMP in pacemaker cell starts at ~-_____mV
~ -55mV
When MP of P cell gets to -40mV, there is opening of v-g ________ channels (depolarization)
Ca-Na channels
Pacemaker cells are VERY leaky to _____ ions; we don’t have to have a stimulus applied to generate AP bc of this!
Sodium
In P cells, after opening of v-g Ca-Na channels, MP gets to peak amplitude, _____mV, _____ channels close, and ______ channels open (repolarization); MP moves back down to RMP
~+20mV
V-g Ca-Na channels close
K channels open
Rate of AP generation: 60-100/min
Overrides lower, slower potential pacemakers
SA node (normal pm)
Inherent rate 40-60/min
AV node/jxn
Inherent rate 15-40/min
Ventricular purkinje fibers
_________ pacemakers can occur anywhere in the conduction system.
Ectopic
