Chapter 18 Heart Flashcards
1
Q
what is another name and the function for the entire right section of the heart?
A
pulmonary pump
pumps deoxygenated blood to lungs
2
Q
what is another name and the function for the entire left section of the heart?
A
systemic pump
pumps oxygenated blood to entire body
3
Q
where is the heart located within the body?
A
in the mediastinum cavity
2/3 left of the midline
4
Q
where does the base of the heart point?
A
points towards right shoulder (up)
5
Q
where does the apex of the heart point?
A
points towards left hip (down)
6
Q
what is the apical impulse?
A
tapping of the apex of heart against 5th intercostal space
happens when left ventricle contracts (systole)
7
Q
Describe the names of all layers of the pericardium
A
fibrous outermost layer
parietal layer of serous pericardium
pericardial cavity
visceral layer of serous pericardium (AKA: epicardium)
8
Q
what is fibrous pericardium composed of?
A
tough, dense irregular connective tissue (similar to that of tendons)
9
Q
what is the fibrous pericardium’s function?
A
protect
anchor
prevent overfilling
10
Q
what is inside the pericardial cavity?
A
serous fluid
11
Q
what is the function of the serous pericardium membranes and cavity?
A
to reduce friction
12
Q
what is pericarditis?
A
peri - around
cardi - heart
itis - inflammation
inflammation of the pericardium
roughens serous membrane and heart rubs against pericardium
13
Q
how can you tell someone has pericarditis?
A
creaking sound in stethoscope
deep pain over sternum
14
Q
what can cause pericarditis?
A
infections
tissue death of the heart
15
Q
what is cardiac tamponade?
A
“heart plug”
large amount of fluid accumulating in PERICARDIAL CAVITY causes heart inability to pump/expand
16
Q
What can cause cardiac tamponade?
A
prolonged pericarditis
17
Q
How can we treat cardiac tamponade?
A
cardiocentesis:
cardio - heart
centesis - puncture w/hollow needle
drain fluid with catheter (not a permanent solution - need to find the root cause)
18
Q
what are incompetent valves?
A
leaky/ improperly functioning valves within the heart
19
Q
why are incompetent valves dangerous?
A
can cause backflow
cause inadequate blood flow to tissues
20
Q
how can you diagnose incompetent valves?
A
abnormal heart sounds
21
Q
what are two ways we can treat incompetent valves?
A
mechanical replacements (made from metal)
organic replacements (made from cadavers/ pig valves/ reconstructed w/ cow pericardium)
22
Q
what are pros/cons of using mechanical replacement valves in the heart?
A
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
23
Q
what ways are biosynthetic valves made safe for humans?
A
tissue is treated and antigens are removed so that it won’t be rejected
24
Q
what is a mitral valve prolapse?
A
left A.V. valve is prolapsed and bulges upwards toward the left atrium, due to chordae tendinea not holding mitral valve sufficiently in place
25
how common is having a mitral valve prolapse?
fairly common - effecting 1% of population
but 7% chance of finding in autopsy
26
what can mitral valve prolapse lead to?
incompetent valve
irregular heartbeat
pain
shortness of breath
27
what is an angina pectoris?
brief spasm causing brief loss of blood to myocardium
28
what can cause an angina pectoris?
stress
physical activity
29
Is an angina pectoris life-threatening?
not necessarily
muscle cells weaken but do not die
30
what is a myocardial infarction? What causes it? 
a heart attack
caused by prolonged coronary artery blockage from blood clots or plaque
31
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
32
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
33
Describe the layers of the heart (without the pericardium)
epicardium
myocardium
endocardium
34
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
35
describe what the myocardium is
middle muscular layer of the heart
thickest on the left ventricle side of the heart
36
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
37
describe the endocardium
lines chambers and valves
is continuous with lining of blood vessels that lead out of the heart
38
what is the endocardium made of?
white, smooth endothelium that contains squamous epithelial cells on layer of connective tissue
39
what is the function of the endocardium?
reduces friction between blood and heart
40
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
41
42
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
43
what is the generic name for the valves that connect either atria to its ventricle?
A.V. valve - atrioventricular valves
44
what is the generic name for the valves that connect either ventricle to its designated artery?
S.L. valve - semilunar valve
45
when do the A.V. valves open?
when there is more pressure in the atria than the ventricles
46
when do the AV valves close?
when the ventricles contract (to prevent backflow)
47
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
48
what is the function of the chordae tendineae?
when ventricles contract, tugging of the cord occurs to keep the AV valves closed during contraction
49
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
50
when do the SL valves open?
when pressure in ventricles is greater than pressure in arteries
51
when do the SL valves close?
when ventricles relax, blood flows backward and fills the cusps closed
52
what is another name for chordae tendineae?
heart strings
53
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
54
name three similarities between AV and SL valves
both have cusps
both prevent backflow
both are flaps of connective tissue
55
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
56
How many microns is the diameter of a RBC?
8-10 microns
57
Sketch the heart's layers (and their brief function), atrium, ventricles, valves, arteries, veins, and direction of blood flow
58
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
59
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)
60
if the coronary arteries are blocked, what will happen?
oxygen will not be delivered to the heart causing a heart attack
61
what is the function of cardiac veins?
collect blood and dump it back to the heart
62
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
63
list 6 cardiac defect and a brief description
64
which is the least likely to be life-threatening?
angina pectoris or mitral valve prolapse
65
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)
66
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
67
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)
68
Venn diagram skeletal muscle and cardiac muscle
69
how long does it take for cardiac muscle cells to die from lack of oxygen?
1-3 hours
70
what does ischemia mean?
inadequate supply of blood to tissue/organ
71
do cardiac muscle cells have a lack of mitochondria or an abundance?
an abundance (10x more than skeletal muscle)
72
do skeletal or cardiac muscle cells have a short/long refractory period
skeletal - short refractory period
cardiac - long refractory period
73
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)
74
sketch the pathway of blood flow through the heart
75
Name characteristics of pacemaker cells
do not contract
spontaneously produce action potential
located specifically along conduction pathways
gap junctions
76
describe the resting membrane potential that pacemaker cells have? what is the value that pertains to?
unstable resting membrane potentials
-60 mV
77
Draw the action potential for pacemaker cells. Indicate which ion channels are opening and closing
78
what is the SA node?
sinoatrial node: small mass of pacemaker right the right atrial wall that initiates heartbeat
79
how many impulses does the heart generate?
spontaneously generates 75 impulses
80
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
81
why are there no gap junctions between the atrial and ventricular myocardium?
so that when atria contract, the ventricles do not also contract
82
what is the internodal pathway?
connect SA to AV node so that it can begin to initiate AV node impulse
83
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
84
how many impulses does the AV node generate?
50 impulses per minute
85
which node malfunctioning can cause death?
AV node not working can cause death (produces impulse that later causes ventricles to contract)
86
what is the atrioventricular bundle?
connects AV node to ventricles
splits into left and right bundle branches
87
what are the Perkinje fibers? their job?
smaller branches of the atrioventricular bundles
depolarize contractile cells of ventricles and papillary muscles
88
how many ms between SA node to systole?
220 ms
89
order the sections of the cardiac conduction system in the order of which the depolarization wave travels through them
90
what structure allows pacemaker cells and cardiac muscles to depolarize from the same impulse?
gap junctions
91
what is the resting membrane for contractile cells?
-90 mV
92
draw the action potential for contractile cardiac muscle cell. Indicate which ion channels are opening and closing
93
what does the term absolute refractory period mean?
time when cell absolutely cannot depolarize again
94
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
95
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
96
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
97
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
98
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
99
what is fibrillation?
rapid and irregular contraction of cardiac muscle
100
what is an ectopic focus?
inappropriate region of the heart controls rhythm
101
what can cause ectopic focus?
ischemic damage to conduction pathways
stimulants
fever
102
what can cause fibrillation?
tachycardia
uncorrected arrythmia
ectopic focus
103
what is a heart block?
damage to AV node or AV bundle
104
what is first degree heart block?
depolarization (signal to contract) is delayed for too long
105
what is second degree heart block?
only some of the impulse are transmitted (ventricular contractions are missing only some of the time)
106
what is third degree heart block?
no action potentials pass to the ventricles (complete heart block)
107
what is asystole?
a: without
systole: systole/contraction
period when heart fails to contract
no electrical signals (flatline)
108
true or false. All cardiac muscle has an unstable resting membrane potential?
false; contractile cells have a stable resting membrane potential
109
which ion is most directly responsible for depolarization in pacemaker cells?
Ca 2+
110
what is happening during systole?
ventricles contract/ atria is relaxed
111
what is happening during diastole?
ventricles relax/ atria contract
112
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)
113
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
114
what does EDV stand for and mean?
End Diastolic Volume: amount of blood in ventricles at fullest point
115
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
116
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
117
what does ESV stand for/mean?
End Systolic Volume: ventricles are at their emptiest
118
draw the cardiac cycle in 5 hearts. Include direction blood is flowing and indicate which valves are open/closed.
119
true/false: during ventricular ejection, the atria are relaxed
true
120
which valves open at the end of isovolumetric relaxation?
AV
121
How many times during a single cardiac cycle are all four valves closed?
2
122
how many times during a single cardiac cycle are all four valves open?
none
123
what is stroke volume?
how much blood leaves half of the heart
124
how do you calculate the stroke volume?
EDV - ESV = stroke volume
125
what 3 factors cam cause stroke volume to change?
preload
afterload
contractility
126
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
127
what is the frank-starling law state?
heart will pump any amount of blood delivered to it in a single stroke
128
increasing venous return increases what?
preload
129
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
130
what is contractility
measures the forces of heart
131
what are inotropic effectors?
drugs that can increase/decrease contractility
132
what are positive inotropic effectors?
increase contractility
133
what are negative inotropic effectors?
decrease contractility
134
what effect to stroke volume will an increase of preload have?
increased preload = increased stroke volume
135
what effect to stroke volume will an increase of afterload have?
increase afterload = decreased stroke volume
136
what effect to stroke volume will an increase of contractility have?
increased contractility = increased stroke volume
137
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)
138
what can be a negative inotropic effector?
acidosis - excess H+
high extracellular K+
calcium channel blockers - decreases time of contraction
139
what is average heart rate?
75 bpm
140
what are positive chronotropic effectors?
increase heart rate
141
what are examples of positive chronotropic effectors?
activation of SN system
thyroid hormone
heat
142
what is the measure of tachycardia
greater than 100 bpm at rest
143
what is tachycardia caused by?
fever
stress
drugs (caffeine/cocaine)
heart disease
144
what can fibrillation cause?
Blood clots and stroke
145
what are examples of negative chronotropic factors?
activation of Parasympathetic nervous system
cold (temp)
146
what are negative chronotropic factors?
decrease heart rate
147
what is the measure of bradycardia?
less than 60 bpm at rest
148
what can bradycardia be caused by?
hypothermia
drugs (heroin/ THC)
parasympathetic NS activation
149
what is the definition of cardiac output?
the amount of blood pumped out by each ventricle in 1 minute
150
what is the equation associated with cardiac output?
HR x SV = CO
151
what are heart palpitations?
increased force of contraction that causes a noticeable heartbeat
152
what can heart palpitations be indicative of?
mild arrhythmias
153
what is congestive heart failure?
the wall of heat becomes weakened or damaged/ cannot maintain cardiac output
154
what can cause congestive heart failure?
multiple heart attacks
hypertension
155
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
156
what is peripheral congestion?
right side of heart has failed
blood accumulates in systemic circuit
157
what is a common cause of peripheral congestion?
smoking
158
what is fibrosis of the heart?
dead contractile cells have died and are replaced with connective tissues
connective tissues cannot contract
159
what occurs if fibrosis of pacemaker cells has occured?
interferes with electrical conduction
160
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
161
where is blood cells produced?
bone marrow
