Anatomy and physiology Ch 18
Junctional Rhythm
*Def* AV Node becomes the pacemaker of the heart Ventricular Rate: 40-60 bpm Rhythm: Regular QRS: Normal (typically) P Waves: Absent, Hidden in the QRS, inverted (if before the QRS) PR interval: If the P wave is in front of the QRS - less than 0.12 seconds - Short P:QRS ratio: 1:0, 1:1 *S/S:* of reduced cardiac output - Emergency pacing may be needed for bradycardia *Causes:* Increased vagal tone, Complete heart block
Which blood vessel carries blood from the anterior to the posterior of the heart? -left coronary artery -circumflex artery -marginal artery -posterior interventricular artery
circumflex artery
The first heart sound (the "lub" of the "lub-dup") is caused by __________. -atrial contraction -ventricular contraction -closure of the semilunar valves -closure of the atrioventricular valves
closure of the atrioventricular valves
Which of the following terms is correctly matched to its description? -diastole: contraction period -stroke volume: amount of blood pumped out by each ventricle in one minute -quiescent period: total heart relaxation between heartbeats -systole: relaxed period
quiescent period: total heart relaxation between heartbeats
Which of these muscles is particularly associated with anchoring the right and left atrioventricular valves? myocardium pectinate muscles trabeculae carneae papillary muscles
papillary muscles
During which of these stages are the pulmonary and aortic valves open? -phase 1 -phase 2a -phase 2b -phase 3
phase 2b
Which of the following descriptions does NOT describe atrioventricular (AV) valves? -flap-like -open based on pressure changes in the atria versus the ventricles -pocket-like -anchored inferiorly by specialized connective tissue
pocket-like
Which of the following is a branch of the right coronary artery? -coronary sinus -posterior interventricular artery -circumflex artery -anterior interventricular artery
posterior interventricular artery
As your muscles contract during activity, more blood is returned to the heart. Which variable would be affected and what would be the outcome of this action? -End-systolic volume would be increased, which would increase cardiac output. -Preload would be increased, which would increase cardiac output. -Contractility would be increased, which would increase cardiac output. -Afterload would increase, which would increase cardiac output.
preload would be increased, which would increase cardiac output
afterload
pressure venticles have to overcome to eject blood
Medication for VT - Stable acute MI
procainamide
Hypercalcemia could cause ______. -increased osteoclast activity -prolonged T wave -hypersecretion of parathyroid hormone -All of the listed responses are correct
prolonged T wave
sides of the heart and body that are oxygen poor, CO2 strong blood
pulmonary arteries, venae cavae, right atrium, right ventricle
Which of the following does NOT deliver deoxygenated blood to the heart? -coronary sinus -inferior vena cava -pulmonary veins -superior vena cava
pulmonary veins
Which of these vessels returns blood to the left atrium of the heart? superior vena cava coronary sinus pulmonary veins pulmonary trunk
pulmonary veins
What does the P-R interval represent?
PR interval represents the time needed for *sinus node stimulation*, *atrial depolarization*, and *conduction through the AV node before ventricular depolarization* --- Reflects the conduction of an electrical impulse through the SA node through the AV node. The PR interval is measured from the beginning of the P wave to the *beginning* of the QRS complex.
Slight decrease in pacing rate due to expiration-activated inhibition of the SA node is controlled by what?
Parasympathetic stimulation - Sinus pacing is regulated by both divisions of the ANS
Because depolarization slows within the AV Node, there is a brief delay or ____ before depolarization is conducted to the ventricles? Why does depolarization slow when the wave enters the AV Node?
Pause To allow time for the blood in the atria to enter the ventricles - producing a brief pause after the P wave.
what is caused by the intrinsic conduction system
fibrillation and arrhythmias
Electrophysiology (EP) studies
During EP studies, the patient is awake and may experience symptoms related to the arrhythmia - during the procedure, the arrhoxythmia will be reproduced under controlled conditions. (pg 751)
tachycardia
abnormally fast heart rate
The right side of the heart is considered the systemic circuit pump. T/F?
False The right side of the heart pumps oxygen-poor blood to the lungs to be re-oxygenated. For this, the right side of the heart is considered the pulmonary circuit pump
The role of the chordae tendineae is to open the AV valves at the appropriate time. T/F?
False The role of the chordae tendineae is to anchor the AV valves against the large pressure changes that occur as the ventricles contract.
Nonparoxysmal Junctional Tachycardia
*Def* Enhanced automaticity in the junctional area - resulting in a rate of 70-120 bpm. Ventricular Rate: *70-120 bpm* Rhythm: Regular QRS: Normal (typically) P Waves: Absent, Hidden in the QRS, inverted (if before the QRS) PR interval: If the P wave is in front of the QRS - less than 0.12 seconds - Short P:QRS ratio: 1:0, 1:1 Indicative of serious conditions --> Dig tox, myocardial ischemia, hypokalemia, COPD
Premature Atrial Complex - PAC
*Def:* An electrical impulse starts in the atrium before the next normal impulse of the SA node. Resulting in a depolarization stimulus -- seen as an earlier than normal P wave on the EKG. Caused by an irritable atrial automaticity focus -- caffeine, alcohol, nicotine, stretched atrial myocardium, anxiety, hypokalemia, preganacy, infarction/ischemia. *Rate:* Underlying Rhythm (Normally: Sinus Tachycardia) *Rhythm*: Irregular - From irregular early P waves. *QRS*: The QRS complex which follows the early/weird p wave is typically normal (because pacing activity resets) May be abnormally wide- aberrant conducted PAC Hidden - Blocked PAC
Torsades de Pointes
*Def:* Polymorphic VT preceded by a prolonged QT interval *Causes* - CNS disease; low levels of potassium, calcium, magnesium; congenital; certain medications Rhythm requires medical treatment - patient becomes pulse-less and deteriorates quickly. *Tx* - Correct the electrolyte imbalance, admin of isoproternol (Isuprel) IV, initiation of ventricular pacing. Possible tx: magnesium. *Appearance:* Outline looks like a twisted ribbon Rate - 250-350 bpm - brief episodes
Premature Ventricular Complex (PVC)
*Def:* Premature ventricular beat - producing a giant ventricular complex on EKG (Great width, enormous amplitude [height and depth], opposite in polarity of the normal QRS complexes) *Causes:* Hypoxia (Most likely). Other: Caffeine, nicotine, alcohol, HF, tachycardia, dig tox, acidosis, hypokalemia *Rate:* Underlying rate *Rhythm*: Irregular *P Wave*: Hidden (in the QRS or T wave), in front of the QRS, or following the QRS complex with a different shape *PR Interval:* If the P is in front of the QRS - then the PR interval would be less than 0.12 seconds *QRS:* Wide (> 0.10 sec), bizarre appearance *P: QRS Ratio*: 0:1, 1:1 Typically there is a "compensatory" pause after a PVC S/S - The effect of PVCs depend on the timing in the cardiac cycle Prognosis - Not serious Tx - PVCs that are frequent/persistent - treated with amiodarone, sotalol - Long term medication therapy is not indicated.
Atrial Flutter
*Def:* Rapid succession of identical, back-to-back, atrial depolarization waves (flutter waves) at a rate of 200-400 bpm. There is a therapeutic block from at the AV node preventing impulses from being conducted into the ventricular (This prevents the ventricle rate from also being 200-400). *Ventricular Rate:* Typically 75-150 *QRS:* Normal, abnormal, absent *P waves:* Saw tooth shape - Called "F" waves *P:QRS* ratio: 2:1, 3:1, 4:1 *S/S:* SOB, CP, Hypotension *Tx:* Electrocardioversion, medications used to slow ventricular response rate (Beta-blockers, digitalis), catheter ablation Who? Patients with COPD, valvular disease, and thyrotoxicosis, following open heart and repair of cardiac defects.
where are the pulmonary vavle heard
2nd inter coastal space at left sternal margin
where are aortic valve sounds heard
2nd intercoastal space at the right eternal margin
T wave represents
Final *rapid* phase of ventricular repolarization - during which the ventricular repolarization occurs quickly and effectively
SA Node Rate Normal
60-100/min The SA Node generates pacing impulses at a constant unvarying rate, producing cycles of equal length, so the rhythm of the heart is said to be regular.
What is the average normal pH range of blood?
7.35-7.45
At what rate does the sinoatrial (SA) node depolarize?
75 times per minute
Heart murmurs caused by a stenotic mitral valve ______. -are detected while blood flow into the left ventricle is reduced -are detected due to the turbulent blood flow that occurs as blood backflows into the left atrium -are detected if the valve's cusps are thin and flexible -All of the listed responses are true.
Are detected while blood flow into the left ventricle is reduced
Atrial Fibrillation
AF (Atrial Fibrillation) is caused by many irritable parasystolic atrial foci firing at rapid rates. No single impulse depolarizes the atria completely (*no P waves*), and only an occasional, random atrial depolarization reaches the AV Node to be conducted to the ventricles; this produces *irregular ventricular (QRS) rhythm.* Irregular ventricular and atrium rhythm Rate: Atrial rate is 300-600, ventricular rate is normally 120-200 in untreated AF QRS Shape: Normal No P waves P:QRS ratio: Many: 1 Nursing Implication: You must determine and document the general ventricular rate in A-fib (QRS per six second strip times ten)
Which of the following structures collects the depolarization wave from the atria to pass it onto the ventricles? -AV node -atrioventricular bundle -bundle branches -SA node
AV node
Which of the following structures receives the depolarization wave from the atria and passes impulses onto the ventricles?
AV node
Atroventricular Nodal Reentry Tachycardia AVNRT
AVNRT occurs when -- an impulse is conducted to an area in the AV node that causes the impulse to be rerouted into the same area over and over again at a very fast ventricular rate. Benign dysrhthmia. *Onset/Cessation* -- Abrupt *Rate* --- 150- 250 Atrial Rate, 120-200 ventricular rate *QRS Complex* --- Usually narrow (< 120 ms) unless pre-existing bundle branch block, accessory pathway, or rate related aberrant conduction *S/S* --- Palpitations,Restlessness, CP, SOB, Pallor, Hypotension, LOC *Causes* ----Caffeine, nicotine, hypoxemia, stress. Underlying causes --- CAD, cardiomyopathy, occurs more often in females due to underlying structural heart disease *Tx* --- Catheter ablation, vagal maneuvers, bolus of adenosine followed with larger doses or with a calcium channel blocker, cardioversion (If heart does not respond to medication)
Ventricular Asystole
Absent QRS complexes confirmed in *two* different leads, although P waves may be apparent for a short duration. No heartbeat, no palpable pulse, no respiration Prognosis: Fatal Tx: High quality CPR (focus on chest compression), intubation, establishment of IV access, After 2 minutes (5 cycles of CPR) a bolus of IV Epi is administered and repeated at 3-5 minute intervals -Admin of atropine bolus IV administered soon after rhythm check -Possible admin of vasopressin for the first or second dose of epi Possible causes: Hypoxia, acidosis, severe electrolyte imbalance, drug overdose, hypovolemia, cardiac tamponade, tension pnemothorax, hypothermia
During A-Fib no single impulse completely depolarizes both _____, so there are no ____ waves, just rapid series of tiny, erratic spikes on EKG.
Atria - P waves
The Q wave, when present always occurs at the _______ of the QRS complex and is the first downward deflection of the complex.
Beginning
Causes of P*V*Cs
Behaviors: Caffeine, alcohol,nicotine Ischemia/infarction Increased work load on the heart - HF, tachycardia Dig Tox Electrolyte imbalances - hypokalemia
calculation of cardiac output
CO=heart rate x stroke volume
what happens at pacemaker cells threshold
Ca2+ channels open and theres an explosive Ca2+ influx which produces the rising phase of the action potential
Cell-to-cell conduction of depolarization through the myocardium is carried by sodium ions, however, AV Node conduction is due to the slow movement of which ions?
Calcium Ca++
Which of the following is NOT a difference between cardiac and skeletal muscle? -Cardiac muscle does not use the sliding filament mechanism for contraction; skeletal muscle does. -Cardiac muscle cells quickly die in the absence of oxygen; skeletal muscle cells are better able to adapt to oxygen deficiency. -The plasma membranes of cardiac muscle cells interlock, but skeletal muscle fibers are independent. -Cardiac muscle cells contain more mitochondria than do skeletal muscle cells.
Cardiac muscle does not use the sliding filament mechanism for contraction; skeletal muscle does
The release of free calcium ions into the interiors of the myocytes produces - myocardial ______?
Contractions Ca++ ions cause myocyte contraction
QT interval represents
Duration of ventricular systole (contraction) - reflects the time from ventricular depolarization (positive state) through re-polarization (negative resting state) Clinical significance: Good indicator of repolarization. Patients with long QT intervals (more than half of the R-to-R interval; more than 0.32-0.4 in a normal HR) are at risk for dangerous ventricular rythms
Ventricular Tachycardia
Defined as three or more PVCs in a row occurring at a rate exceeding 100 bpm. *Emergency* - Patient is typically unresponsive and pulse-less Ventricular Rate - 100-200 bpm Atrial Rate - Depends on underlying rhythm Rhythm - Usually regular QRS Shape/Duration - 0.12 seconds or more -- Bizarre, Abnormal Shape P wave - Hidden - Atrial rate and rhythm may be difficult to detect PR interval - Very irregular if P waves are seen P:QRS ratio - Difficult to determine - if P waves are present, there are more QRS complexes than P waves Tx: Antiarrhythmic medications, anti-achycardia pacing, direct cardioversion. For pulseless VT - Dfibrillation.
In general, when you see an upward wave on an EKG you know that it represents a _______ wave moving toward the positive electrode?
Depolarization waves are represented as upwards waves on an EKG
P wave represents:
Electrical activity (depolarization) of both atria - also thus, represents the simultaneous contraction of the atria [This simultaneous contraction of the atria forces blood to pass through the AV valves between the atria and the ventricles]
Depolarization
Electrical stimulation (cells interiors become positive) - causing mechanical contraction of ventricles - systole
The right side of the heart is considered the systemic circuit pump.
FALSE The right side of the heart pumps deoxygenated (oxygen-poor) blood into the pulmonary circuit of the lungs to be re-oxygenated. For this reason, the right side of the heart is considered the pulmonary circuit pump. The left side of the heart pumps blood into the systemic circuit, which serves the tissues of the body, and is therefore considered the systemic circuit pump.
Why are gap junctions a vital part of the intercellular connection of cardiac muscles?
Gap junctions allow action potentials to spread to connected cells.
What is a hematocrit?
Hematocrit is the percentage of erythrocytes in a whole blood sample. Although the percent sign is usually omitted, the hematocrit, which in this figure is 45, is the percentage of erythrocytes in whole blood. The height of the erythrocyte layer is divided by the total height of the material.
Idioventricular Rhythm
Idioventricular Rhythm - AKA - Ventricular Escape Rhythm Purkinje fibers become the pacemaker of the heart. How? The SA node has failed to create an impulse (exl - from increased vagal tone) and the AV node also cannot be conducted through (exl - from complete AV block). *Ventricular Rate*: *20-40 bpm* If exceeds 40 bpm then rhythm is accelerated idioventricular rhythm (AIVR) *Rhythm:* Regular *QRS Shape/Duration:* Bizarre, abnormal shape, duration of 0.12 seconds or more *S/S* of reduced cardiac output, LOC *Tx:* ID the underlying cause, admin of epi, atropine, vassopressor medications, initiating emergency transcutaneous pacing. If no S/S, bedrest.
sinusoidal capillary
Most permeable. Occurs in special locations (e.g., liver, bone marrow, spleen).
Repolarization
Myocardial cells return to negative resting state
Premature ventricular contractions (PVCs) are considered precursors of ventricular tachycardia (VT) when they _______?
Occur at a rate of more than six per minute, they indicate increasing ventricular irritability and are considered forerunners of VT. PVCs are dangerous when they occur on the T wave. PVCs are dangerous when they are multifocal (have different shapes).
Premature Junctional Complex
P Wave: *Inverted or absent* PR Interval: Absent or short - less than 0.12 seconds Rhythm: Regular with premature beats QRS: Normal *Rate: Underlying rate* *Def* Irritable automaticity focus in the AV junction fires a premature stimulus that is conducted to and depolarizes the ventricles.(The AV node is how the ventricles are normally activated) *Causes* Dig Tox, HF, CAD
Following depolarization, repolarization is due to the controlled outflow of ___ ions from the myocytes?
Potassium (K+) ions Potassium ions cause repolarization of myocytes
How is repolarization accomplished?
Potassium (K+) ions leaving the myocytes
Depolarization of the ventricular myocytes produces a ______ on the EKG and initiates contraction of the ventricles?
QRS complex In other words - the QRS complex is an electrocardiographic recording of ventricular depolarization.
The first upward wave of the QRS complex is the ___?
R wave
U wave
Repolarization of the Purkinje fibers (takes longer than ventricular repolarization) - The end of the T wave marks the end of the ventricular repolarization; however, repolarization of the Purkinje fibers terminates a little later -- after the T wave. This final repolarization of the Purkinje fibers may produce a small hump - the U wave, following the T wave.
Sinus "Arrhythmia"
SA Node pacing rate normally varies with respiration - not a true arrhythmia. Typical minimal increases and decreases.
The order of impulse conduction in the heart, from beginning to end, is __________.
SA node, AV node, bundle of His, bundle branches, and Purkinje fibers
Electrical impulses pass through the conduction system of the heart in the following sequence:
SA node, AV node, bundle of His, bundle branches, and Purkinje fibers The impulses of the heart originate at the SA node (pacemaker). The impulse is then transmitted to the AV node (atrioventricular node), where the impulse slows down to allow the atria to completely contract and thereby fill the adjacent ventricles. The AV node then transmits the impulse to the bundle of His, which branches into left and right bundle branches. The bundle branches give rise to the Purkinje fibers, which transmit the impulse to the ventricle walls and stimulate ventricular contraction.
Which statement is correct regarding the ventricles? -The left ventricle empties into the pulmonary circuit. -The left ventricle has a thinner wall than the right ventricle. -The right ventricle forms a complete circle in cross section. -The right ventricle empties into the pulmonary trunk.
The right ventricle empties into the pulmonary trunk
Which ion movement produces cell-to-cell depolarization of the heart?
Sodium Na+
Slight increase in pacing heart rate due to inspiration activated stimulation of the SA node is controlled by what?
Sympathetic stimulation - Sinus pacing is regulated by both divisions of the ANS
Ventricular depolarization initiates ventricular contraction persists through both phases of re-polarization to the end of the _____ wave?
T wave
Continuous capillaries are the most common capillaries in the body.
TRUE Continuous capillaries, found in the skin, muscles, lungs and CNS, are the most common capillaries. Fenestrated capillaries are found only in sites of active filtration or absorption. Sinusoidal capillaries are limited to a few organs, like the spleen, bone marrow, liver, and adrenal medulla.
ST segment represents
The *initial* phase of ventricular repolarization- but ventrical repolarization is rather *minimal* during the ST segment. Re-polarization of the ventricular myocytes begins immediately after the QRS and persists until the end of the T wave.
The QRS complex represents:
The QRS complex on the ECG strip represents ventricular depolarization. Atrial repolarization usually occurs at the same time as ventricular depolarization and is impossible to distinguish on the ECG. The T wave represents ventricular repolarization. The P wave represents atrial depolarization.
Adding a chemical that reduces Na+ transport near the sinoatrial (SA) node would have what effect on the heart's intrinsic conducting system?
The SA node would depolarize less quickly, reducing the heart rate.
What would happen to the SA node if a chemical blocker was used to reduce transport of Na+ into the pacemaker cells?
The SA node would depolarize more slowly, reducing the heart rate. Diffusion of Na+ into the pacemaker cell causes a gradual depolarization of the cell membrane, called the pacemaker potential. If the rate of depolarization slows down, it will take longer for the membrane to reach threshold and trigger the next action potential, which will reduce heart rate.
Normal order of conduction through the heart is ____?
The correct sequence of conduction through the normal heart is the SA node, AV node, bundle of His, right and left bundle branches, and Purkinje fibers.
Which description is INCORRECT for the layers of the heart and its serous membranes? - The fibrous pericardium prevents overfilling of the ventricles. - The endocardium is the deepest of the layers related to the heart. -The parietal pericardium is on the deep side of the fibrous pericardium. -The epicardium is also considered the parietal pericardium.
The epicardium is also considered the parietal pericardium.
Which of the following nursing interventions must a nurse perform when administering prescribed *vasopressors* to a patient with a cardiac dysrhythmia?
The nurse should *monitor the patient's vital signs and cardiac rhythm* for effectiveness of the medication and for side effects and should always have emergency life support equipment available when caring for an acutely ill patient. The side effects of vasopressor drugs are hypertension, dysrhythmias, pallor, and oliguria.
"Holiday heart" syndrome
This is the association of heart dysrhythmias, especially atrial fibrillation, with binge drinking
Where does ventricular systole begin and how long does it persist for - as seen on an EKG?
Ventricular systole (contraction) begins with the QRS and persists until the end of the T wave. So, ventricular contraction (systole) spans depolarization and repolarization of the ventricles
Ventricular Fibrillation
V-Fib is caused by rapid-rate discharges from many irritable, parasystolic ventricular automaticity foci, producing an erratic, rapid twitching of the ventricles. Totally erratic appearance and lack of any identifiable waves on the EKG. Ventricular Rate: >300 bpm
Synchronization of cardioversion prevents the discharge from occurring during the vulnerable period of which of the following?
Ventricular re-polarization (T wave), which could result in ventricular tachycardia (VT) or ventricular fibrillation.
T wave represents:
Ventricular re-polarization (heart cell interiors return to resting negative state)
when is ventricluar repolarization
after the T wave accurs
Medication for VT - Unstable or impaired cardiac function
amiodarone
Blood enters the left and right coronary arteries directly from which vessel or chamber? -pulmonary trunk -aorta -circumflex artery -left ventricle
aorta
where does ventricluar repolarization began
apex and causes the T wave
where does venticular depolarization began
at apex causing QRS to complex -> atrial repolarization occurs
where is the atrial depolarization impulse delayed
at the AV node
the sinoatrial node
at the top of the right atrium and generates impulses
what does interatrial septum seperate
atria
what causes the P wave
atrial depolarization initiated by the SA node
what bundle connects the the atria to the ventricles
atrioventricular bundle
where do the impulses pause during intristic conduction
atrioventricular node
What best describes afterload? -back pressure exerted by arterial blood -contractility of cardiac muscle -cardiac reserve -degree of stretch of the heart muscle
back pressure exerted by arterial blood
what do the bundle branches conduct
conduct the impulses through the interventricular septum
The source of blood carried to capillaries in the myocardium would be the ________.
coronary arteries
what is pericardial friction rub and what do you use to hear it
creaking sound heard with the stethoscope
cardiac skeleton
crisscrossing, interlacing layer of connective tissue it anchors cardiac muscle fibers, supports great vessels and valves, limits spread of action potentials to specific paths
what does the vagus nerve do? (parasympothetic)
decreases heart rate
what do the subendocardial conducting network do
depolarizes the contractile cells of both ventricles
what causes unstable resting membrane or pacemaker potential
due to opening of slow Na+ channels continuously depolarize
what defects may SA node cause
ectopic focus or axtrasystole
heart physiology
electric events and setting the basic rhythm
fenestrated capillary
endothelial cells have filtration pores facilitating exchange
what are the parts of the heart chamber
epicardium (visceral layer of serous pericardium), myocardium, endocardium, heart chamber
Which of the following would increase cardiac output? -parasympathetic stimulation -high blood pressure -epinephrine -decreased calcium during contraction
epinephrine
cardiac tamponade
excess fluid sometimes compresses heart limiting pumping ability
Which of these is a condition marked by premature ventricular contraction?
extrasystole
Which is most responsible for the synchronized contraction of cardiac muscle tissue?
gap junction
how does the heartbeat coordinate a function
gap junction
where does blood go after it is oxygenated and in the aorta
goes to the body and systemic capillaries
cardiac muscle
has many mitochondria -great dependence on aerobic respiration -little anaerobric respiration ability
myocardial infarction
heart attack
what defects may AV nodes cause
heart block
What causes heart sounds? -heart valve closure -pressure of blood in the ventricles -opening of heart valves -blood flowing from the atria into the ventricles
heart valve closure
where are the tricuspid valve heard
in the right sternal margin of 5th inter coastal space
results in repolarization
inactivation of Ca2+ channels and opening of voltage-gated K+ channels
what two conditions severely weaken heart
incompetent valve and valvular stenosis
what do sympathetic cardiac nerves do?
increase heart rate and cause contraction
Which of the following is NOT a factor that increases stroke volume? -increasing afterload -increasing sympathetic stimulation -increasing preload -increasing contractility
increasing afterload
pericarditis
inflammation of the pericardium roughens membrane surfaces
The plateau phase of an action potential in cardiac muscle cells is due to the _______.
influx of Ca2+ through slow Ca2+ channels
What structures connect the individual heart muscle cells? -chordae tendineae -trabaculae carneae -intercalated discs -anastomoses
intercalated discs
What is the period during the cardiac cycle when the ventricles are completely closed and blood volume in them remains constant as the ventricles contract? -ventricular ejection -ventricular filling -isovolumetric relaxation phase -isovolumetric contraction phase
isovolumetric contraction phase
what is hypertension
it increases afterload and resluts in increased ESV and reduced SV
anastomosis
junction of vessels in the middle of the heart
continuous capillary
least permeable and most common
Which heart chamber receives oxygenated blood from the lungs? right ventricle right atrium left atrium left ventricle
left atrium
sides of the heart and body that are oxygen rich, CO2 poor blood
left atrium, left ventricle, pulmonary veins, aorta and branches
Failure in a particular chamber of the heart tends to cause a backup of blood in the lungs, known as pulmonary congestive heart failure. Failure of which chamber of the heart would lead to such a backup?
left ventricle
Failure in a particular chamber of the heart tends to cause a backup of blood in the lungs, known as pulmonary congestive heart failure. Failure of which chamber of the heart would lead to such a backup? -right ventricle -right atrium -left atrium -left ventricle
left ventricle
Which chamber of the heart sends oxygenated blood to the systemic circuit via the aorta? -right ventricle -right atrium -left atrium -left ventricle
left ventricle
Failure in a particular structure of the heart tends to cause a backup of blood in the lungs, known as pulmonary congestive heart failure. Failure of which structure of the heart would lead to such a backup?
left ventricle Failure in the left ventricle can cause increased blood hydrostatic pressure in the lungs, causing fluid buildup in the alveoli.
intrinsic cardiac conduction system
network of non contractile cells initiate and distribute impulses-> coordinated depolarization and contraction of heart
where is the miltral sounds heard
over heart apex in 5th intercoastal space in line with middle clavical
The presence of an incompetent tricuspid valve would have the direct effect of causing ______. -reduced efficiency in the delivery of blood to the lungs -reduced efficiency in the delivery of blood to the myocardium -reduced efficiency in the delivery of blood from the lungs to the heart -reduced efficiency in the delivery of blood from the head to the heart
reduced efficiency in the delivery of blood to the lungs
fossa ovalis
remnant of foramen ovale of fetal heart
Into which chamber of the heart do the superior vena cava, inferior vena cava, and coronary sinus return deoxygenated blood? -right atrium -right ventricle -left atrium -left ventricle
right atrium
The right atrioventricular valve prevents backflow of blood from the right ventricle into the __________. left atrium left ventricle pulmonary trunk right atrium
right atrium
A blockage in which of these vessels could cause a myocardial infarction in the lateral right side of the heart? -right marginal artery -circumflex artery -anterior interventricular artery -posterior interventricular artery
right marginal artery
age related changes affecting the heart
sclerosis and thickening of vavle flaps, decline in cardiac reserve, fibrosis of cardiac muscle
interventricular septum
seperates ventricles
Specifically, what part of the intrinsic conduction system generates the original stimulus that reaches the atrioventricular (AV) node, allowing it to conduct impulses to the atrioventricular bundle? -subendocardial conducting network (Purkinje fibers) -sinoatrial (SA) node -interventricular septum -bundle branches
sinoatrial (SA) node
Specifically, what part of the intrinsic conduction system stimulates the atrioventricular (AV) node to conduct impulses to the atrioventricular bundle?
sinoatrial (SA) node The sinoatrial node, by spontaneously depolarizing faster than the atrioventricular node, initiates heart contraction.
The most permeable capillaries, which contain fenestrations and large intercellular clefts, are called __________.
sinusoid capillaries Sinusoid capillaries are the most permeable type of capillary due to large fenestrations and intercellular clefts among their endothelial cells. These capillaries allow large molecules-even blood cells- to pass into the surrounding tissue. Sinusoid capillaries are found in the liver, bone marrow, spleen, and adrenal medulla.
The anatomy of the intrinsic conduction system causes contraction of the ventricles to begin at the apex and move superiorly. Why is this important? -because the Purkinje fibers conduct action potentials away from the heart apex -so the atria can finish contracting before the ventricles contract -so blood is forced upward, toward the semilunar valves -because the AV bundle is the only electrical connection between the atria and the ventricles
so blood is forced upward, toward the semilunar valves
myocardium layer of the heart
spiral bundles of contractile cardiac muscle cells
Which of the following increases stroke volume?
stroke volume
preload
the amount of stretch of cardiac muscle cells before they contract (frank starling law of heart)
where is the blood coming from before it enters the heart through the heart
the lungs or pulmonary capillaries
angina pectoris
thoracic pain
The __________ valve is located between the right atrium and the right ventricle. -mitral -pulmonary semilunar -tricuspid -aortic semilunar
tricuspid
does sympathetic activity go up or down with excersize
up (so parasympathetic activity goes down)
what is complete after repolarization occurs ->
venticular depolarization
At what point in the cardiac cycle is pressure in the ventricles the highest (around 120 mm Hg in the left ventricle)? -mid-to-late diastole (ventricular filling) -mid-to-late diastole (atrial contraction) -early diastole (isovolumetric relaxation) -ventricular systole
ventricular systole
