Test 2 Flashcards
The heart is a ______________-chambered muscular organ approximately the size of a fist.
Four
Where is the heart positioned?
Mid-mediastinum of the chest, behind the sternum.
Approximately ⅔ of the heart lies to the left of the midline of the sternum between which two ribs?
2nd and 6th ribs
The apex of the heart is formed by the tip of the left ventricle and lies above the diaphragm at the level of the ____________________.
5th intercostal space to the left.
The base of the heart is formed by the_________________.
Atria and projects to the right, lying below the 2nd rib.
Posteriorly, where does the heart rest?
Level of the 5th to the 8th thoracic vertebrae.
Externally, surface grooves called _________________ mark the boundaries of the heart chambers.
Sulci
The heart is enclosed in a sac called the _________________.
Pericardium
A thin layer of fluid called the _____________________ separates the two layers of the serous pericardium.
Pericardial fluid
Tough, loose-fitting outer layer and inelastic sac surrounding the heart.
Fibrous pericardium
Serous pericardium consists of what two layers?
- Visceral layer
- Parietal layer
Which layer of serous pericardium is the inner lining of the fibrous pericardium?
Parietal layer
Which layer of the pericardium covers the outer surface of the heart and great vessels?
Visceral layer
Inflammation of the pericardium.
Pericarditis
An abnormal amount of fluid can accumulate between the layers of the pericardium resulting in a ________________________.
Pericardial effusion
What is a cardiac tamponade?
When excess pericardial fluid compresses the heart muscle, leading to a serious decrease in blood flow to the body. This, ultimately, may lead to shock and death.
Cardiac tamponade ultimately may lead to _____________________.
- Shock
- Death
The heart wall consist of three layers. What are they?
- Outer epicardium
- Middle myocardium
- Inner endocardium
A cardiac tamponade should be suspected in patients presenting with: (8)
Beck’s Triad
- Muffled heart sounds
- Hypotension
- Jugular venous distention
- Pulsus paradoxus
- Tachycardia
- Tachypnea
- Narrowing pulse pressure
- Severe dyspnea
Which layer of the heart composes the bulk of the heart muscle?
Myocardium
The heart consists of how many valves and chambers?
8!!!
Each AV ring is composed of dense connective tissue termed annulus fibrosus cordis which encircles the bases of the pulmonary trunk, aorta, and heart valves and electrically isolates the aorta from ______________.
The ventricles
____________ are two thin-walled “cups” of myocardial tissue that contribute little to the total pumping activity of the heart.
Atrial chambers
The vascular system has two major subdivisions: What are they?
- Systemic circulation
- Pulmonary circulation
What’s the other name for epicardium?
Visceral layer
What does CPR mimic?
Cardiac output
Which type of pericardium consists of two layers?
Serous pericardium
Can electrical impulses be transmitted through the heart muscle and connective tissue from the atria to the ventricles?
No.
What is regurgitation?
Back flow of blood through a malfunctioning leaky valve.
The two atrial chambers are separated by ________________________.
An interatrial wall or septum.
On the right side of the interatrial septum is an oval depression called the ______________.
Fossa ovalis cordis
Two lower chambers of the heart make up the bulk of the heart’s muscle mass and does most of the pumping that circulates the blood.
Ventricles
The right and left ventricles are separated by a muscle wall called _________________________.
Interventricular septum
The AV valves close during systole, what does this prevent?
Back flow of blood into the atria.
The free ends of the AV valves are anchored to papillary muscles of the endocardium by the _____________________.
Chordae tendineae cordis
During systole, _________________ prevents the AV valves from swinging upward into the atria.
Papillary muscle
Damage to the either the chordae tendineae cordis or the papillary muscles can impair the function of the __________.
AV valves and cause leakage upward into the atria.
What is stenosis?
Pathologic narrowing or constriction of a valve outlet.
What happens with mitral stenosis?
High pressure in the left atrium back up into the pulmonary circulation. Those high pressures can cause:
-Pulmonary edema
-Diastolic murmur
_________________ prevent backflow of blood into the ventricles during systole
Semilunar valves
Two main coronary arteries, one in the right and one in the left, arise from the ___________________________.
Root of the aorta right underneath the semilunar valves.
When does blood flow through the coronary arteries?
Only during diastole when the semilunar valves are closed.
Partial obstruction of a coronary artery can lead to _______________________.
Tissue ischemia (decreased oxygen supply)
Complete obstruction of a coronary artery may cause _______________________.
- Tissue death
- Myocardial infarction
________________________ is the name given to three types of CAD.
Acute Coronary Syndrome
What are the 3 names of the acute artery disease types?
- Unstable angina or angina pectoris
- Non-ST segment elevation myocardial infarction (NSTEMI)
- ST segment elevation myocardial infarction (STEMI)
What condition remains responsible for approximately one-third of all deaths in people over age 35?
Heart disease
What are classic signs of tissue ischemia?
- Chest pain
- SOB
Resulting in a clinical condition called angina pectoris.
What are classic signs of an MI? (5)
- Pain or tightness in the chest, back, arms, neck.
- Fatigue
- Lightheadedness
- Abnormal heart beat
- Anxiety
Nearly how many middle aged men and women in the USA will develop a CHD?
Men: 1/2
Women: 1/3
Coronary veins gather together into large vessel called the ___________________.
Coronary sinus
The coronary sinus empties into the ___________________.
Right atrium
Where does the thebesian veins empty?
Into all of the heart chambers.
Any deoxygenated blood coming from the thebesian veins that enters the left atrium or ventricle lowers the overall oxygen content of the _______________.
Systemic circulation
Because the thebesian veins bypass or shunt around the pulmonary circulation as part of the normal anatomy, this phenomenon is called an ______________.
Anatomic shunt
Normal anatomic shunts account for approximately ______% of total cardiac output.
2-3%
The performance of the heart as a pump depends on its ability to:
- Initiate and conduct electrical impulses
- Synchronously contract the heart’s muscle quickly and efficiently
The ability of cells to respond to electrical, chemical or mechanical stimulation.
Excitability
What can increase myocardial excitability? (3)
- Electrolyte imbalances
- Congenital cardiac anomalies
- Certain drugs
Can lead to cardiac arrhythmias
The unique ability of the cardiac muscle to initiate a spontaneous electrical impulse (depolarization and repolarization).
Inherent rhythmicity or automaticity
What are the heart’s primary pacemakers?
- SA node
- AV node
An electrical impulse from any source other than a normal heart pacemaker is considered what?
Abnormal or ectopic heartbeat
The ability of the myocardial tissue to spread and conduct electrical impulses.
Conductivity
Abnormal conductivity can affect ______________________.
Timing of the chamber contractions and decrease cardiac efficiency.
_________________, in response to an electrical impulse, is the primary function of the myocardium.
Contractility
The period during which the myocardium cannot be stimulated is called ____________________.
The refractory period.
It lasts approximately 250 ms, nearly as long as the heart contraction or systole.
Individual cardiac fibers are enclosed in a membrane called the _________________.
Sarcolemma
Cardiac fibers are separated by irregular transverse thickenings of the sarcolemma called ___________________.
Intercalated discs
Explain Starling’s law of the heart, also known as Frank-Starling law.
The more a cardiac fiber is stretched, the greater the tension it generates when contracted.
Where does the systemic circulation begin and end?
Begins: Aorta on the left ventricle
Ends: Right atrium
Where does the pulmonary circulation begin and end?
Begins: Pulmonary artery out of the right ventricle
Ends: Left atrium
Venous or deoxygenated blood from the head and upper extremities enters the right atrium from the _______.
SVC
Venous blood from the abdomen and lower body enters from the ______.
IVC
_____________________ are the only arteries in the blood that carry deoxygenated or venous blood.
Pulmonary arteries
The systemic circulation has three major components. What are they?
- Arterial sytem
- Venous system
- Capillary system
This system consists of large, highly elastic, low-resistance arteries and small, muscular arterioles or vary resistance.
Arterial system
What is referred as conductance vessels?
Large arteries
What is referred as resistance vessels?
Small arterioles
What plays a major role in the distribution and regulation of blood pressure?
Arterioles
________ controls blood flow into the capillaries.
Arterioles
_________________ are commonly referred as exchange vessels.
Capillaries
This system maintains a constant exchange of nutrients and waste products for cells and tissues of the body.
Capillary system
Cardiac Output equation
CO= HR x SV
P wave represents ___________________.
Atrial depolarization
T wave represents ___________.
Ventricular repolarization
The left atrium pumps blood into the left ventricle and the blood is then pumped to the body through the _____.
AORTA!
Blood flows into the network by an _________ and out through a ________. Direct communication between these vessels is called _______.
Blood flows into the network by an arteriole and out through a venule.
Direct communication between these vessels is called arteriovenous anastomosis.
Capillaries have smooth muscle rings at their proximal ends called ____.
Precapillary sphincters
What happens when precapillary sphincters contract and relax?
- Contraction: decreases blood flow locally
- Relaxation: Increases local perfusion
_________ and ___________ allow precise control over the direction and amount of blood flow to a given organ or area of tissue.
Sphincters and bypasses
This system consist of small, expandable venules and veins and larger, more elastic veins.
Venous system
At any given time, the veins and venules hold approximately __________ of the body’s total blood volume.
2/3
The components of the venous system, especially the small, expandable venules and veins are termed _____.
Capacitance vessels
What must the venous system overcome to return blood to the heart?
Gravity
What four mechanisms aid the venous return to the heart?
- Sympathetic venous tone
- Skeletal muscle pumping or “milking”
- Cardiac suction
4. Thoracic pressure differences caused by respiratory efforts; often called the thoracic pump
Why is thoracic pressure differences caused by respiratory efforts; often called the thoracic pump so important to RTs?
Artificial ventilation with positive pressure reverses normal thoracic pressure gradients.
Does PPV assists with venous return?
No, it impedes it.
What type of patients are vulnerable to a reduction in CO when PPV is applied to the lungs?
Hypovalemic or in cardiac failure
The right side of the heart generates a systolic pressure of ___________ to drive blood through the low-resistance, low-pressure pulmonary circulation.
25 mm Hg
The left side of the heart generates systolic pressures of _________ to propel blood through the high pressure, high-resistance systemic circulation.
120 mm Hg
Blood flow through the vascular system is opposed by what?
Frictional forces
The sum of all frictional forces opposing blood flow through the systemic circulation is called ___________.
SVR - Systemic Vascular Resistance
The beginning pressure of the systemic circulation is the ________.
Mean Aortic Pressure
The ending pressure of the systemic circulation is the ________.
Right atrial pressure or CVP
Resistance to blood flow in the pulmonary circulation is approximately _______ of that of the systemic circulation.
One-tenth
Is pulmonary circulation characterized as a low-pressure, low resistance or high-pressure, high resistance system?
Low-pressure, low resistance system
Is systemic circulation characterized as a low-pressure, low resistance or high-pressure, high resistance system?
High-pressure, high resistance system
What is the priority of the cardiovascular system?
Maintain perfusion pressures to tissues and organs at functional levels, even under changing conditions.
MAP is directly related to the ______________ and inversely related to _______________.
MAP is directly related to the volume of blood in the vascular system and inversely related to its capacity.
MAP = Volume/Capacity
MAP (Mean Arterial Pressure) Equation
MAP = CO x SVR
In a normal adult, MAP ranges from ____.
80-100 mm Hg
MAP is regulated by changing what?
Either changing the volume of circulating blood, the capacity of the vascular system or both
Does vasoconstriction cause BP to increase or decrease?
Increase
Does vasodilation cause BP to increase or decrease?
Decrease
Vascular space decreases when ____ occurs.
Vasoconstriction
Vascular space increases when ____ occurs.
Vasodilation
Define vasoconstriction.
Constriction of the smooth muscles in the peripheral blood vessels.
Define vasodilation.
Constriction of the smooth muscles in the arterioles.
What happens when MAP decreases below 60 mm Hg?
Perfusion to the brain and kidney are severely compromised and organ failure may occur in minutes.
The MAP is one of the first variables that is monitored in __________.
Septic patients
Define prolonged hypotension.
MAP of less than 60-65 mm Hg.
What is the cardiovascular system responsible for?
Transporting metabolites to and from the tissues under various conditions and demands.
Stroke Volume Equation.
SV = EDV-ESV
EDV ranges for normal persons.
110-120 mL
What is ECGs primarily used for?
To help evaluate a patient with signs/symptoms of cardiac disease.
What are some reasons why the Dr. would order an ECG? (6)
Patients complaining of:
- Chest pain
- SOB
- Dyspnea with palpations
- Weakness
- Lethargy
- Syncope
What is this called?
Stimulation of the polarized cells cause an influx of Na+ into the interior portion of the cell.
Depolarization
Depolarization causes the cardiac muscle cells to _____.
Contract
Which part of the body is most sensitive to changes in the local metabolite levels?
Brain
The total amount of blood pumped by the heart per minute.
Cardiac output
SV is affected primarily by intrinsic control of what three factors?
- Preload
- Afterload
- Contractility
The heart does not eject all of the blood it contains during systole. Instead, a volume called the ____, remains inside the ventricles.
End-systolic volume
EF equation
EF = SV/EDV x 100
An increase in SV occurs when either…
- EDV increases
- ESV decreases
A decrease in SV occurs when either…
- EDV decreases
- ESV increases
_______ in preload (EDV) and _____ in ESV result in increased SV in the healthy heart.
Increases in preload (EDV) and decreases in ESV result in increased SV in the healthy heart.
____ in afterload can decrease SV, especially in the failing heart by increasing the ESV.
Increases in afterload can decrease SV, especially in the failing heart by increasing the ESV.
Drugs that increase contractility of the heart muscle are called __.
Positive inotropes
Drugs that decrease contractility of the heart muscle are called __.
Negative inotropes
___ and ____ impair myocardial function and decrease cardiac contractility and CO.
- Profound hypoxia
- Acidosis
The impulse-conducting system cells have the ability to stimulate the heart without ______.
Influence of the nervous system
A rapid return of the cell to the “polarized” position.
Repolarization
The impulse-conducting system has three type of cardiac cells capable of electrical excitation:
- Pacemaker cells (SA and AV node)
- Specialized rapidly conducting tissues (Purkinje fibers)
- Atrial and ventricular muscle cells
The ability of cardiac cells to depolarize without stimulation.
Automaticity
The impulse-conducting system is responsible for what?
Initiating the heartbeat and controlling the heart rate. Also coordinates the contraction of the heart chambers.
Where is the SA node located?
In the upper portion of the right atrium.
______ has the greatest degree of automaticity and paces the heart.
SA node
A defect in the impulse-conducting system may lead to:
- Inadequate CO
- Decreased tissue perfusion
Define ectopic beat.
Any heartbeat originating outside of the SA node.
The SA node is innervated by the ___.
Autonomic nervous system
- Sympathetic and parasympathetic nervous system influence HR.
The electrical impulse generated by the SA node travels across the right atrium through intraatrial pathways, to left atrium by the way of ___.
Bachmann bundle
____ is the backup pacemaker of the heart.
AV node
AV node paces ventricular activity at what rate?
40-60 beats/min
Where is the AV node located?
Intraventricular septum
Why is the eletrical impulse temporarily delayed at the AV node?
To allow the ventricles time to fill with blood.
Normally the QRS complex is shorter than _____.
0.12 second
In the first degree heart block, the PR interval is longer than _____.
0.12 second
Type II heart block is seen as a series of _________.
Nonconducted P waves followed by a P wave that is conducted to the ventricles.
Treatment is usually not needed for first-degree heart block if the patient is able to ____.
Maintain adequate BP
Ventricular tachycardia is a run of _________________.
3 or more PVCs.
When atrial muscles quivers in an irregular pattern that does not result in a coordinated contraction.
Atrial fibrillation
Where is V1 placed?
4th intercostal space to the right of the sternum.
Where is V6 placed?
5th intercostal space at the midaxillary line
The wave of depolarization in the atria is seen as the _____ on an ECG.
P wave
What’s the size of the P wave?
- 2.5 mm high
- 3 mm long
What may cause the P wave to enlarge to a larger height and length?
Atrial hypertrophy
Why is atrial repolarization not seen on an ECG?
It’s obscured by the electrical activity occurring in the ventricles at the same time.
Ventricular depolarization is seen as the ____ on an ECG.
QRS complex
Why is the QRS complex much larger than the P wave?
Muscle mass of the ventricles is greater than the atria.
QRS complex
The first wave of the complex is negative (downward), it’s labeled the _____.
Q wave
QRS complex
The initial positive (upward) deflection is referred as the ____.
R wave
QRS complex
The next negative deflection after the R wave is labeled the ___.
S wave
What wave represents ventricular repolarization?
T wave
Typical PR interval is ________ long.
0.12 to 0.20 seconds
_____ refers to the distance (time) between the start of atrial depolarization and the start of ventricular depolarization.
PR interval
What does a PR interval longer than 0.20 seconds represents?
The impulse is abnormally delayed at the AV node and a “block” is present.
_____ represents the times from the end of ventricular depolarization to the start of ventricular repolarization.
ST segment
Cells that conduct the electrical impulse throughout the heart.
Conducting cells
Cells that contract in response to electrical stimuli and pump blood
Myocardial cells
Specialized cells that have a high degree of automaticity and provide electrical power for the heart
Pacemaker cells
What does an inverted T wave suggest?
Ischemia of the heart muscle
Abnormal configuration of the T wave occurs with _____.
Electrolyte abnormalities such as hyperkalemia (where the T wave take a “peaked” or sharper than normal appearance)
What is the most life-threatening arrhythmia?
Ventricular fibrillation