Chapter 18: Cardiology Flashcards
the heart is located directly behind the __
sternum
what is the base of the heart?
superior part
in what part of the heart are the major blood vessels?
base
what is the apex of the heart?
inferior, pointed tip
how many sides in the heart? how many chambers?
2; 4
role of right atrium
receives blood from systemic circuit
role of right ventricle
pumps blood into pulmonary circuit
role of left atrium
receives blood from pulmonary circuit
role of left ventricle
pumps blood into systemic circuit
what is the pericardium?
sac-like structure wrapped around the heart
what are the 3 layers of the pericardium>
fibrous and 2 serous
what is the fibrous pericardium? what is it made of?
outermost layer; dense fibrous connective tissue that extends to sternum and diaphragm
what are the two layers of the serous pericardium?
outer parietal layer and inner serous layer
what is the pericardial cavity?
space between serous layers, containing pericardial fluid secreted from serous membranes
what is the function of the pericardial fluid?
to lubricate movements of the heart
what is pericarditis
inflammation of pericardium
cardiac tamponade
excess accumulation of pericardial fluid
what are the 3 layers of the heart?
- pericardium
- myocardium
- endocardium
what is the epicardium?
visceral layer of serous pericardium
what is the myocardium made of ?
concentric layers of cardiac muscle
what is the role of the myocardium?
support blood vessels and nerves
what is the endocardium made up?
simple squamous epithelium and areolar tissue
the endocardium is continuous with the __ and covers heart __
endothelium; valves
arterial muscle of the myocardium wraps around atria in ___ pattern
figure 8
what are the 2 layers of ventricular musculature of the myocardium?
sperficial and deeper
the superficial layer of the ventricular musculature surrounds __
both ventricles
deeper layers of the ventricular musculature are arranged in what way?
around and between the ventricles
T/F cardiac muscle cells are smaller than skeletal muscle cells
true
how many nuclei in a cardiac cell
1
cardiac cells have ___ that allow branching interactions between cells
intercalated discs
t/f cardiac muscle is striated
true
cardial muscle is almost entirely dependent on ___ for energy
aerobic metabolism
cardiac muscle has abundant stores of __ and __ for oxygen
mitochondria and hemoglobin
cardiac muscle has extensive __
capillaries
intercalated discs are interconnected with the __ of adjacent cells
plasma membrane
intercalated discs are attached by __ and __
desmosomes and tight junctions
gap junctions between intercalated discs allows ___ to spread cell to cell which allows cells to functions as a __
action potentials; unit
what structures are visible on the anterior surface? (4)
- all four chambers
- auricle
- coronary sulcus
- anterior inter ventricular sulcus
what is the auricle of each atrium?
an expandable pouch
what is the coronary sulcus?
groove separating atria and ventricles
what is the anterior inter ventricular sulcus?
groove marking boundary between the two ventricles
what structures are visible on the posterior surface? (5)
- all 4 chambers
- pulmonary veins (4) returning blood to left atrium
- superior and inferior vena cavae returning blood to right atrium
- coronary sinus
- posterior interventricular sulcus
what is the role of the coronary sinus?
returns blood from myocardium to right atrium
___ continually supplies cardiac muscle (myocardium) with oxygen/nutrients
coronary circulation
____ arise from ascending aorta; fill when ventricles are relaxed (diastole)
left and right coronary arteries
myocardial blood flow may increase up to __x the resting level during maximal exertion
9
what is supplied by the right coronary artery?
right atrium, both ventricles, and parts of the cardiac conducting system
what are the 2 main branches of the right coronary artery?
- marginal arteries
2. posterior interventricular (posterior descending) artery
what is supplied by the marginal artery?
right ventricle
what is supplied by the interventricular artery?
interventricluar septum and adjacent parts of ventricles
what is supplied by the left coronary artery?
left ventricle, left atrium, interventricular septum
what are the 2 main branches of the left coronary artery?
- anterior interventricualr artery ( left and anterior descending)
- circumflex artery
what is supplied by the circumflex artery?
posterior of left ventricle
the circumflex artery follows the _- sulcus to the left and meets branches of the ___ posteriorly
coronary; coronary artery
location of great cardiac vein
in anterior interventricuar sulcus
what is the function of the great cardiac muscle? what does it drains and where does it empty into?
drains area supplied by anterior interventricluar sulcus and empties into coronary sinus
what does the anterior cardiac veins drain and empty to?
drain anterior surface of right ventricle; empty into right atrium
what is the coronary sinus?
expanded vein that empties into right atrium
the posterior vein or left ventricle drains the area supplied by the __
circumflex artery
the middle cardiac vein drains area supplied by __ and empties into the __
posterior interventricular artery; coronary sinus
the small cardiac vein drains __ and empties into __
posterior of right atrium/ventricle; coronary sinus
blood flow through the coronary circuit is maintained by changing __ and __
blood pressure; elastic rebound
left ventriclar contraction forces blood into the __. what does this do to blood pressure
aorta; raises blood pressure
what happens to blood pressure and aortic walls during left ventricular relaxation?
pressure decreases; aortic walls recoil (elastic rebound)
left ventricular relaxation forces blood in what 2 directions?
- forward into systemic circuit
2. backward into coronary arteries
the left and right atria are separated by the _-
interatrial septum
right and left ventricles are separated by __
interventricular septum
atrioventricular valves allow only ___ blood flow from __- to __
one-way; atrium to ventricle
location of semilunar valves
at exit of each ventricle
semilunar valves allow only ___ blood flow from __ into __ or __
one-way; ventricle; aorta or pulmonary trunk
the right atrium receives __ blood from ___ and __
deoxygenated; superior/inferior venue cavae and coronary sinus
what is the fossa ovals?
remnant of fetal foramen ovale that allowed fetal blood to pass between atria (closes at birth)
the left atrium receives __ blood from __
oxygenated; pulmonary veins
the right ventricle receives blood from ___ through __ valve
right atrium; tricuspid
what is another name for tricuspid valve?
AV valve
contraction of right ventricle forces blood through the ___ valve into the __
pulmonary semilunar valve; pulmonary trunk
t/f the left ventricle is much thicker than the right
t
the left ventricle receives blood from the ___ through the __ valve
left atrium; mitral valve
what is another name for the mitral valve?
bicuspid valve
with contraction of the left ventricle, blood exists through the __ into the __
aortic semilunar valve; ascending aorta
the cusps of the AV valves attach to __
cord tendoneae
the chordae tendoneae are anchored to thickened cone-shaped ___
papillary muscles
what is the moderator band?
thickened muscle ridge providing rapid conduction
the moderator band tenses __ just before ventricular contraction and prevents ___ of AV valve
papillary muscles ; slamming or inversion
which ventricle has thinner walls and pumps blood with minimal effort and low pressure?
the right
which ventricle sends blood to the entire systemic circuit
left
which ventricle sends blood to the pulmonary trunk?
right
during ventricular relaxation, what causes the semilunar valves to remain shut
blood pressure form pulmonary and systemic circuits
during ventricular contraction, what keeps the AV valves closed?
pressure of contracting ventricle and the cordae tendoneae are tightened by the papillary muscles to keep cusps from inverting
what happens if the AV cusps invert during ventricular contraction?
regurgitation (backflow)
to open the semilunar valves, the ventricular pressure overcomes the pressure in the __ and ___
pulmonary trunk; aorta
what is the cardiac skeleton?
flexible connective tissue frame
the cardiac skeleton is made of interconnected bands of ___ and encircles the __ to stabilize their positions
dense connective tissue; heart valves, base of aorta and pulmonary trunk
the cardiac skeleton electrically isolates the ___ of the atria and ventricle
myocardium
how many cusps on a semilunar valve?
3
the semilunar valves prevent back flow from __ and ___
aorta and pulmonary trunk
do the semilunar valves require muscular brace? why/whynot
no, because the cusps support each other
what is valvular heart disease?
valve function deteriorates until heart cannot maintain adequate blood flow
what is arteriosclerosis
thickening/toughening of arterial walls
what is coronary artery disease?
arteriosclerosis of the coronary vessels
arteriosclerosis of the rain can lead to __
strokes
what is atherosclerosis?
formation of lipid deposits in the arterial tunica media and damage to the endothelium
what is the most common form of arteriosclerosis?
atherosclerosis
atherosclerosis is often associated with elevated __
blood cholesterol
what forms in the vessels due to atherosclerosis?
plaque
what are the two ways of treating atherosclerosis?
- replace damaged segment of vessel
2. compressing plaque with balloon angioplasty
a balloon angioplasty is most effective for what types of plaques?
small, soft
t/f there is a very low surgical mortality associated with a balloon angioplasties
true
coronary artery disease is characterized by
areas of partial or complete blockage of coronary circulation
what is coronary ischemia?
reduced blood flow to the heart
coronary artery disease is usually caused by what 2 things
atherosclerosis in a coronary artery or associated blood clot
what is the medical term for a blood clot?
thrombus
the cardiac cycle is the period between __ and ___
start of one heartbeat and the next
what are the 2 phases of the cardiac cycle?
systole and diastole
at the beginning of the cardiac cycle, all 4 chambers are __n
diastole
during diastole, what is happening to the ventricles?
passively filling
what happens during atrial systole?
atria contract and ventricles finish filling
after atrial systole, the atria are then in __ for the rest of the cardiac cycle
diastole
what happens in the first phase of ventricular systole?
contracting ventricles push AV valves closed, but no enough pressure to open semilunar valves
what type of contraction occurs in the first phase of ventricular systole?
isovolumetric contraction
what happens in the 2nd phase of ventricular systole?
increasing pressure opens semilunar valves
what type of contraction occurs in the 2nd phase of ventricular systole?
ventricular ejection
what happens in early ventricular diastole
ventricles relax and their pressure drops, blood in aorta and pulmonary trunk back flows, closes semilunar valves
what happens during isovolumetric relaxation?
all valves closed, no volume change, blood passively filling the atria
what happens during late ventricular diastole?
all chambers relaxed, AV valves open and ventricles passively fill
T/F tetanic contractions occur in cardiac muscle
false
t/f the refractory period for cardiac muscle continues into relaxation
true
T/F cardiac muscle has short actions potentials
false, long
what are the 3 stages of cardiac muscle action potential?
- rapid depolarization
- plateau
- depolarization
what happens during rapid depolarization?
voltage gated fast sodium channels open
what happens during g the plateau stage?
fast sodium channels close and Na is actively pumped out, slow calcium channels open
what happens during depolarization?
slow calcium channels close and slow potassium channels open
what is cardiac output?
amount of blood pumped from left ventricle each minute
cardiac output is determined by ___ and ___
heart rate and stroke volume
t/f the cardiac output is precisely adjusted to meet the needs of tissues
t
cardiac output = ___ x___
heart rate x stroke volume
heart rate is measured as
number of contractions per minute
stroke volume is measured as
volume of blood pumped out of ventricle per contraction
what is autorhymicity?
cardiac muscles ability to contract at ts own pace independent of neural or hormonal stimulation
what is the conducting system?
network of specialized cardiac muscle cells that initiate/distribute a stimulus to contract
what are the 5 components of the conducting system?
- SA node
- internodal pathways
- atrioventricular node
- AV bundle and bundle branches
- purkinje fibers
the SA node acts as the __
pacemaker
each heartbeat begins with an action potential started in the __
SA node
where if the SA node located?
in the posterior wall of the right atrium, near the superior vena cava
the internal pathways are formed by __ cells
conducting
the internodal pathways distribute signals through both __
atria
the AV nodes relay signals from __ to __
atria to ventricles
the AV nodes have __ cells that can take over if _ fails
pacemaker; pacing in SA node
T/f the pacing of the AV is faster than that of the SA node
false, slower
the AV bundle has __ cells that transmit signal through __
conducting; interventricular septum
which bundle branch is larger?
left
__ cells of the bundle branches transmit signals to __ then spread out in __
conducting; apex of heart; ventricular walls
the purkinje fibres radiate upward through __
ventricular walls
the purkinje fibres propagate action potentials as fast as __
myelinated neurons
the purkinje fibres stimulate __ and trigger __
ventricular myocardium; contraction
what is an electrocardiogram? (ECG/EKG)
recording of heart’s electrical activities from the body surface
an ECG assesses the performance of
nodal, conducting, and contractile components
t/f appearance of ECG differs with placement and number of electrodes
true
the P wave represents
arterial depolarization
the QRS complex represents
ventricle depolarization
ventricle depolarization has a larger wave due to __
Larger ventricle muscle mass
ventricles begin contracting shortly after __ wave peak
R
atrial depolarization also occurs after __ wave, but is not visible because __
R; masked by QRS
what does the T wave represent?
ventricular repolarization
what happens during the P-R interval?
start of arterial depolarization to start of ventricular depolarization
a P-R interval >200msec may mean __
damage to conducting pathways or AV node
what is the Q-T interval
time for ventricles to undergo a single cycle
the Q-T interval may be lengthened by __
electrolyte imbalances, medications, conduction problems, coronary iscemia, myocardial damage
what is a cardiac arrhythmia?
abnormal patterns of cardiac electrical activity
t/f about 5% of healthy people experience a few abnormal heartbeats each day
t
t/f cardiac arrhythmia is not a clinical issue unless the pumping efficiency is reduced
t
what is pacemaker potential?
the gradual spontaneous depolarization
pacemaker potential in the SA node establishes __
heart rate
parasympathetic stimulation ___ (increases/decreases) heart rate
decreases
Each from the parasympathetic neutrons opens __ channels in the plasma membrane which slows rate of __ and lengthens rate of __
K+; depolarization; depolarization
binding of norepinephrine from sympathetic neutrons increases __- and decreases __
depolarization; depolarization
a normal heart rate ranges from __to __
60-100
bradycardia
lower than normal heart rate
tachycardia
higher than normal heart rate
what are the 2 cardiac centers in the medulla oblongata ?
- cardioinhibitory center
2. cardioacceleratory center
what is the end-diastolic volume?
blood in the ventricle at the end of ventricle diastole
what is the end systolic volume?
blood in the ventricle at the end of systole
the amount of blood pumped out is the __ volume
stroke
stroke volume = ___ -___
EDV-ESV
venous return
amount of venous blood returned to the right atrium
venous return varies based on __, __ and __
blood volume, muscular activity, rate of blood flow
what is filling time?
length of ventricular diastole
what is preload?
amount of myocardial stretch
what are the factors affecting stroke volume?
end diastolic volume, preload, contractility, afterload
what is the Frank-Starling law of the heart?
greater EDv causes greater preload; more stretching causes stronger contractions and more blood being ejected
what is contractility ?
amount of force produced during contraction at a given preload
contractility is increased by __
sympathetic stimulation, some hormones
contractility is reduced by
beta blockers and calcium channel blockers
what is after load?
ventricular tension required to open semilunar valves and empty
as after load increases, stroke volume __
decreases
after load increases whenever blood flow is
constricted
cardiac output can be changed by affecting either _ or __
heart rate or stroke volume
heart failure
condition in which the heart cannot meet the demands of peripheral tissues
