Chapter 18 Heart Flashcards
what is another name and the function for the entire right section of the heart?
pulmonary pump
pumps deoxygenated blood to lungs
what is another name and the function for the entire left section of the heart?
systemic pump
pumps oxygenated blood to entire body
where is the heart located within the body?
in the mediastinum cavity
2/3 left of the midline
where does the base of the heart point?
points towards right shoulder (up)
where does the apex of the heart point?
points towards left hip (down)
what is the apical impulse?
tapping of the apex of heart against 5th intercostal space
happens when left ventricle contracts (systole)
Describe the names of all layers of the pericardium
fibrous outermost layer
parietal layer of serous pericardium
pericardial cavity
visceral layer of serous pericardium (AKA: epicardium)
what is fibrous pericardium composed of?
tough, dense irregular connective tissue (similar to that of tendons)
what is the fibrous pericardium’s function?
protect
anchor
prevent overfilling
what is inside the pericardial cavity?
serous fluid
what is the function of the serous pericardium membranes and cavity?
to reduce friction
what is pericarditis?
peri - around
cardi - heart
itis - inflammation
inflammation of the pericardium
roughens serous membrane and heart rubs against pericardium
how can you tell someone has pericarditis?
creaking sound in stethoscope
deep pain over sternum
what can cause pericarditis?
infections
tissue death of the heart
what is cardiac tamponade?
“heart plug”
large amount of fluid accumulating in PERICARDIAL CAVITY causes heart inability to pump/expand
What can cause cardiac tamponade?
prolonged pericarditis
How can we treat cardiac tamponade?
cardiocentesis:
cardio - heart
centesis - puncture w/hollow needle
drain fluid with catheter (not a permanent solution - need to find the root cause)
what are incompetent valves?
leaky/ improperly functioning valves within the heart
why are incompetent valves dangerous?
can cause backflow
cause inadequate blood flow to tissues
how can you diagnose incompetent valves?
abnormal heart sounds
what are two ways we can treat incompetent valves?
mechanical replacements (made from metal)
organic replacements (made from cadavers/ pig valves/ reconstructed w/ cow pericardium)
what are pros/cons of using mechanical replacement valves in the heart?
last a long time
but the patient would need to be on blood thinners to reduce the chance for clotting against the foreign object in the heart
what ways are biosynthetic valves made safe for humans?
tissue is treated and antigens are removed so that it won’t be rejected
what is a mitral valve prolapse?
left A.V. valve is prolapsed and bulges upwards toward the left atrium, due to chordae tendinea not holding mitral valve sufficiently in place
how common is having a mitral valve prolapse?
fairly common - effecting 1% of population
but 7% chance of finding in autopsy
what can mitral valve prolapse lead to?
incompetent valve
irregular heartbeat
pain
shortness of breath
what is an angina pectoris?
brief spasm causing brief loss of blood to myocardium
what can cause an angina pectoris?
stress
physical activity
Is an angina pectoris life-threatening?
not necessarily
muscle cells weaken but do not die
what is a myocardial infarction? What causes it? 
a heart attack
caused by prolonged coronary artery blockage from blood clots or plaque
what happens to muscle cells in a myocardial infarction?
muscle cells actually die and can leave the heart unable to beat where death occurred.
if cells are able to replace they are replaced only with connective tissue that leaves scars, which do not function the same as heart tissue
how can we tell if someone has had a heart attack?
viewing bloodwork for traces of CPK (creatine protein kinase) or troponin
when heart muscle cells die, the cell breaks down and proteins leak into the bloodstream. Certain proteins can be found only in live muscle cells and should not be found in the bloodwork unless a heart attack/death of heart muscle cell has occured
Describe the layers of the heart (without the pericardium)
epicardium
myocardium
endocardium
describe what the epicardium is
most superficial layer of the heart
same thing as visceral layer of the serous pericardium
full of fat as we age
describe what the myocardium is
middle muscular layer of the heart
thickest on the left ventricle side of the heart
why is the myocardium thickest on the left ventricle side of the heart?
heart needs to pump significant pressure to get blood to every part of the body
describe the endocardium
lines chambers and valves
is continuous with lining of blood vessels that lead out of the heart
what is the endocardium made of?
white, smooth endothelium that contains squamous epithelial cells on layer of connective tissue
what is the function of the endocardium?
reduces friction between blood and heart
true/ false? most of the heart is in the exact center of the thoracic cavity. If false, where is it located?
false; 2/3 of heart fall left of the body midline
predict what would happen to the myocardium if the right side of the heart had to push against as much pressure as the left side does
the right ventricle wall of myocardium would be thicker
what is the generic name for the valves that connect either atria to its ventricle?
A.V. valve - atrioventricular valves
what is the generic name for the valves that connect either ventricle to its designated artery?
S.L. valve - semilunar valve
when do the A.V. valves open?
when there is more pressure in the atria than the ventricles
when do the AV valves close?
when the ventricles contract (to prevent backflow)
what are the names of specific AV valves? What do they direct blood flow of?
tricuspid valve (AKA: right AV valve) - connects RIGHT atrium and right ventricle
bicuspid valve (AKA: left AV valve/ Mitral valve) - connects LEFT atrium and ventricle
what is the function of the chordae tendineae?
when ventricles contract, tugging of the cord occurs to keep the AV valves closed during contraction
what is the chordae tendineae made of/ attached to?
they are collagen cords attached to papillary muscles located on the side walls of the ventricles. Thereby connecting the AV valves to the ventricular wall
when do the SL valves open?
when pressure in ventricles is greater than pressure in arteries
when do the SL valves close?
when ventricles relax, blood flows backward and fills the cusps closed
what is another name for chordae tendineae?
heart strings
what are the names of the two SL valves and what do they connect?
Aortic SL valve - connects left ventricle to the aorta
pulmonary SL valve - connects right ventricle to pulmonary trunk
name three similarities between AV and SL valves
both have cusps
both prevent backflow
both are flaps of connective tissue
name three differences between AV and SL valves
- the blood flows in different directions (ie: AV valves control blood leaving downward/ SL valves control blood leaving upward)
- only AV valves have chordae tendineae
- AV valves open when ventricles are relaxed/ SL valves open when ventricles contract
How many microns is the diameter of a RBC?
8-10 microns
Sketch the heart’s layers (and their brief function), atrium, ventricles, valves, arteries, veins, and direction of blood flow
what is the function of coronary arteries? what are they connected to?
supply the heart with blood
leave the aorta and wrap towards the left and right of the heart
How do the coronary arteries work?
they deliver blood to the heart when the heart is relaxed through the left and right coronary artery (they are squeezed shut when the myocardium contracts)
if the coronary arteries are blocked, what will happen?
oxygen will not be delivered to the heart causing a heart attack
what is the function of cardiac veins?
collect blood and dump it back to the heart
what are the parts of the cardiac veins and where are they located?
great, middle, small cardiac veins - drain blood into coronary sinus
coronary sinus - drains directly into the right atrium
list 6 cardiac defect and a brief description
which is the least likely to be life-threatening?
angina pectoris or mitral valve prolapse
what are the types of cells found in cardiac tissue? what do they do?
cardiac muscle cells - physically contract
pacemaker cells - controls timing of contraction (do not actually physically contract)
characteristics of cardiac muscle cells
short, fat, possibly branched
one or two nuclei
striated (contain sarcomeres of actin and myosin)
electrically excitable
physically connected at intercalated discs
what are the intercalated discs of cardiac muscle cells composed of? their jobs?
gap junctions - allow ions to move from one cell to next (such as sodium)
desmosomes - physical linkage which keeps tissue from tearing during contraction (think of threads of a seam)
Venn diagram skeletal muscle and cardiac muscle
how long does it take for cardiac muscle cells to die from lack of oxygen?
1-3 hours
what does ischemia mean?
inadequate supply of blood to tissue/organ
do cardiac muscle cells have a lack of mitochondria or an abundance?
an abundance (10x more than skeletal muscle)
do skeletal or cardiac muscle cells have a short/long refractory period
skeletal - short refractory period
cardiac - long refractory period
why do cardiac cells have a long refractory period (what benefit does this posses)?
if heart had short refractory periods, it would be more frequent to spasms or cramps (such as with leg cramps)
sketch the pathway of blood flow through the heart
Name characteristics of pacemaker cells
do not contract
spontaneously produce action potential
located specifically along conduction pathways
gap junctions
describe the resting membrane potential that pacemaker cells have? what is the value that pertains to?
unstable resting membrane potentials
-60 mV
Draw the action potential for pacemaker cells. Indicate which ion channels are opening and closing
what is the SA node?
sinoatrial node: small mass of pacemaker right the right atrial wall that initiates heartbeat
how many impulses does the heart generate?
spontaneously generates 75 impulses
what is Bachmann’s bundle? when it is stimulated, what happens?
originates from SA node and wraps outwards towards around both atria
both atria contract when stimulated/depolarized
why are there no gap junctions between the atrial and ventricular myocardium?
so that when atria contract, the ventricles do not also contract
what is the internodal pathway?
connect SA to AV node so that it can begin to initiate AV node impulse
what is the AV node? what is its job?
atrioventricular node
its job is to bottleneck impulse in order to delay depolarization by 100 ms
how many impulses does the AV node generate?
50 impulses per minute
which node malfunctioning can cause death?
AV node not working can cause death (produces impulse that later causes ventricles to contract)
what is the atrioventricular bundle?
connects AV node to ventricles
splits into left and right bundle branches
what are the Perkinje fibers? their job?
smaller branches of the atrioventricular bundles
depolarize contractile cells of ventricles and papillary muscles
how many ms between SA node to systole?
220 ms
order the sections of the cardiac conduction system in the order of which the depolarization wave travels through them
what structure allows pacemaker cells and cardiac muscles to depolarize from the same impulse?
gap junctions
what is the resting membrane for contractile cells?
-90 mV
draw the action potential for contractile cardiac muscle cell. Indicate which ion channels are opening and closing
what does the term absolute refractory period mean?
time when cell absolutely cannot depolarize again
what would hypercalcemia cause to the action potential of contractile cardiac muscle cells?
hyper - too much
calcemia - calcium in the blood
too much calcium in the blood results in a prolonged plateau
what would hypocalcemia cause to the action potential of contractile cardiac muscle cells?
hypo: insufficient
calcemia: calcium in the blood
insufficient calcium in the blood would reduce the force of each heartbeat
what would hyperkalemia cause to the action potential of contractile cardiac muscle cells?
hyper: too much
kalemia: potassium in the blood
too much potassium in the blood would cause repolarization to happen faster, disrupting heart rhythm
what would hypernatremia cause to the action potential of contractile cardiac muscle cells?
hyper: too much
natremia: sodium in the blood
because sodium is larger than calcium, having too much sodium would clog up calcium channels, leaving calcium unable to get in, resulting in hypocalcemia which causes weaker heart contractions
what is arhythmia?
uncoordinated atrial and ventricular contraction (rhythm out of sync)
often the ventricles contract too soon and do not properly fill with blood
what is fibrillation?
rapid and irregular contraction of cardiac muscle
what is an ectopic focus?
inappropriate region of the heart controls rhythm
what can cause ectopic focus?
ischemic damage to conduction pathways
stimulants
fever
what can cause fibrillation?
tachycardia
uncorrected arrythmia
ectopic focus
what is a heart block?
damage to AV node or AV bundle
what is first degree heart block?
depolarization (signal to contract) is delayed for too long
what is second degree heart block?
only some of the impulse are transmitted (ventricular contractions are missing only some of the time)
what is third degree heart block?
no action potentials pass to the ventricles (complete heart block)
what is asystole?
a: without
systole: systole/contraction
period when heart fails to contract
no electrical signals (flatline)
true or false. All cardiac muscle has an unstable resting membrane potential?
false; contractile cells have a stable resting membrane potential
which ion is most directly responsible for depolarization in pacemaker cells?
Ca 2+
what is happening during systole?
ventricles contract/ atria is relaxed
what is happening during diastole?
ventricles relax/ atria contract
explain the process of ventricular filling and when during systole/diastole does this occur?
mid-to-late diastole
begins when all chambers are relaxed
atrial pressure high, ventricular pressure is low
SL valves are closed
AV valves are open
80% of blood is flowing to ventricles
ends with atrial contraction (last 20% blood to ventricles)
explain the process of isovolumetric contraction and when during systole/diastole does this occur?
early systole
atria relax and ventricles begin contracting
AV valves and SL valves are closed for a split second
ventricles are at fullest point
what does EDV stand for and mean?
End Diastolic Volume: amount of blood in ventricles at fullest point
explain the process of ventricular ejection and when during systole/diastole does this occur?
systole
pressure in ventricles exceeds pressure in large arteries
SL valves open
explain isovolumetric relaxation and when during systole/diastole does this occur?
early diastole
ventricles relax
pressure decrease, SL valves close
AV valves are still closed
what does ESV stand for/mean?
End Systolic Volume: ventricles are at their emptiest
draw the cardiac cycle in 5 hearts. Include direction blood is flowing and indicate which valves are open/closed.
true/false: during ventricular ejection, the atria are relaxed
true
which valves open at the end of isovolumetric relaxation?
AV
How many times during a single cardiac cycle are all four valves closed?
2
how many times during a single cardiac cycle are all four valves open?
none
what is stroke volume?
how much blood leaves half of the heart
how do you calculate the stroke volume?
EDV - ESV = stroke volume
what 3 factors cam cause stroke volume to change?
preload
afterload
contractility
What is preload
degree of stretch (how much blood can you pack into the heart before ejection
the more you put in, the more you get out
what is the frank-starling law state?
heart will pump any amount of blood delivered to it in a single stroke
increasing venous return increases what?
preload
what is afterload?
back pressure from arterial blood vessels
having high after load = less blood leaving the heart/ heart has to push harder to push against the back pressure of aorta
what is contractility
measures the forces of heart
what are inotropic effectors?
drugs that can increase/decrease contractility
what are positive inotropic effectors?
increase contractility
what are negative inotropic effectors?
decrease contractility
what effect to stroke volume will an increase of preload have?
increased preload = increased stroke volume
what effect to stroke volume will an increase of afterload have?
increase afterload = decreased stroke volume
what effect to stroke volume will an increase of contractility have?
increased contractility = increased stroke volume
what can be a positive inotropic effector?
activation of sympathetic nervous system
glucagon
epinephrine/ norepinephrine
digitalis - given to patient’s in congestive heart failure (heart not pumping enough blood)
what can be a negative inotropic effector?
acidosis - excess H+
high extracellular K+
calcium channel blockers - decreases time of contraction
what is average heart rate?
75 bpm
what are positive chronotropic effectors?
increase heart rate
what are examples of positive chronotropic effectors?
activation of SN system
thyroid hormone
heat
what is the measure of tachycardia
greater than 100 bpm at rest
what is tachycardia caused by?
fever
stress
drugs (caffeine/cocaine)
heart disease
what can fibrillation cause?
Blood clots and stroke
what are examples of negative chronotropic factors?
activation of Parasympathetic nervous system
cold (temp)
what are negative chronotropic factors?
decrease heart rate
what is the measure of bradycardia?
less than 60 bpm at rest
what can bradycardia be caused by?
hypothermia
drugs (heroin/ THC)
parasympathetic NS activation
what is the definition of cardiac output?
the amount of blood pumped out by each ventricle in 1 minute
what is the equation associated with cardiac output?
HR x SV = CO
what are heart palpitations?
increased force of contraction that causes a noticeable heartbeat
what can heart palpitations be indicative of?
mild arrhythmias
what is congestive heart failure?
the wall of heat becomes weakened or damaged/ cannot maintain cardiac output
what can cause congestive heart failure?
multiple heart attacks
hypertension
what is pulmonary congestive heart failure?
the left side of heart has failed
only right side of heart is working causing blood accumulates in lungs
causing pulmonary edema
what is peripheral congestion?
right side of heart has failed
blood accumulates in systemic circuit
what is a common cause of peripheral congestion?
smoking
what is fibrosis of the heart?
dead contractile cells have died and are replaced with connective tissues
connective tissues cannot contract
what occurs if fibrosis of pacemaker cells has occured?
interferes with electrical conduction
explain why failure of the left side of the heart causes pulmonary congestive heart failure?
the left side of the heart failed
only the right side of the heart is working
this causes lungs to be filled with pressure/fluid
where is blood cells produced?
bone marrow
