Block 1 - Cardiac Flashcards
(226 cards)
1
Q
Within the right coronary artery, the marginal branch supplies what portion of the heart?
A
The marginal branch supplies the right ventricle.
2
Q
The structures of coronary circulation can be described as the coronary _______, coronary _______, and the coronary ________.
A
arteries; veins; sinus
3
Q
In fetal cardiac anatomy, what structure shunts blood from the pulmonary artery to the arch of the aorta?
A
The ductus arteriousus
4
Q
Pectinate muscles are found in what structures of the heart?
A
the right atrium; right and left auricle
5
Q
What are the three regions (cusps) of the pulmonary valve?
A
anterior semilunar, right semilunar, left semilunar
6
Q
In Frank-Starling Law, ________ is proportional to __________ volume.
A
preload; end-diastolic
7
Q
How many auscultation sites are there for heart sounds?
A
4
8
Q
What special feature is found in the anterior portion of the right atrium; and also found in the left and right auricle?
A
pectinate muscles
9
Q
True or false: An inotrope is something that alters the force of the conductivity.
A
False; force of the contraction.
10
Q
With regard to heart sounds, what causes the sound of the S1?
A
In S1, the blood turbulence caused by the closure of AV valves soon after the ventricular systole begins
11
Q
True or False:
Skeletal muscle can build action potential on top of action potential for stronger contraction.
A
True.
12
Q
What does the right coronary artery divide into?
A
the posterior interventricular branch and the marginal branch
13
Q
Mitochondria make up what percentage in:
Cardiac tissue = ______ % of the cystolic
Skeletal tissue = ______ % of the cystolic
A
25%; 2%
14
Q
True or false: During ventricular dystole the ventricles relax and the atriaventricular valves close and the semilunar valves open.
A
False; the atriaventricular valves open and the semilunar valves close.
15
Q
Choose one:
The posterior interventricular branch lies in the (posterior/anterior) interventricular sulcus and supplies the (posterior inferior / anterior inferior) wall of the (right/left) ventricle and part of the interventricular septum.
A
posterior; posterior inferior; left
16
Q
The action potential (increases / decreases) considerably at the atriaventricular (AV) node.
A
decreases (slows)
17
Q
The “right” heart surface that faces the right lung is mostly made of the _________ .
A
right atrium
18
Q
The S4 heart sound is caused by what?
A
The blood turbulence during atrial systole (contraction).
19
Q
The increased influx through the cell membrane of which cation can alter the action potential and strengthen the contraction?
A
Ca2+
20
Q
An increase in afterload causes stroke volume to __________. This causes more blood to remain in the ventricles.
A.) increase
B.) fluctuate
C.) decrease
D.) rebound
A
C.) decrease
21
Q
The “open end” of the fibrous pericardium is fused to the connective tissues of what cardiac structure?
A
The great vessels; pulmonary trunk
22
Q
Within contractile fibers there is a “resting period” until what occurs?
A
…until a signal (action potential) from conductive fibers occurs
23
Q
Choose one:
Repolarization is the (recovery / activation) within the myocardium.
A
recovery
24
Q
How long, respectively, are these periods:
Atrial systole:
Ventricular systole:
Relaxation period:
A
Atrial systole: .1 second
Ventricular systole: .3 second
Relaxation period: .4 second
25
True or False: The tendon-like cords connected to papillary muscles that connect the cusps of the aortic and pulmonary valves are called the chordae tendineae.
False; the chordae tendineae connect the cusps of the tricuspid and bicuspid valves.
26
What is the term for the .5 second(s) when both the atriaventricular valves and the semilunar valves are closed?
isovolumetric contraction
27
The inferior heart surface is formed by the 2/3rd of the _______ ventricle and 1/3rd of the _________ ventricle and rests on what part of the diaphragm?
left; right; central tendon of the diaphragm
28
The "left" heart surface that faces the left lung and along the pulmonary border is mostly made of the _________.
left ventricle
29
Within the pericardium, the heart is confined to its position in the ______________.
mediastinum
30
What artery lies in the anterior interventricular sulcus and supplies the bulk of the left ventricle (middle to lower portions) and a large portion of the interventricular septum?
The left anterior descending (LAD)/anterior interventricular artery
31
What layer houses the beginning of the blood vessels and lymphatic tissues that supply the all three layers of the heart wall?
the epicardium
32
What two valves are semi-lunar valves?
The pulmonic/pulmonary and aortic valve.
33
Blood passes from the right atrium into the right ventricle through the _________ valve, also known as the right __________ valve.
tricuspid; atrioventricular
34
The left side of the heart leads to which type of closed circuit circulation?
systemic
35
What is the remnant structure of the ductus arteriousus once it is closed (normally) after birth?
The ligamentum arteriousium
36
When pressure in the ventricle falls below the pressure of the atria, what occurs in the atriaventricular valves?
the AV valves open allowing for the ventricle to fill again
37
The anterior heart surface is formed by the 2/3rd of the _______ ventricle and 1/3rd of the _________ ventricle.
right; left
38
What structure in the conductive system initiates an action potential about every .6 seconds?
the sinoatrial (SA) node
39
Once the blood unloads oxygen and other nutrients and picks up carbon dioxide and other wastes in the capillaries, the dexoygenated blood flows into what circulatory system structure?
A.) veins
B.) arteries
C.) venules
D.) the right atrium
C.) venules
40
Inherent rates of the conductive system are:
_____ _____= 60-100 AP/min
_____ _____= 40-60 AP/min
_____ _____ = 20-40 AP/min
Fill in the blank with:
Purkinje Fibers / SA node / AV node
SA Node = 60-100 AP/min
AV Node = 40-60 AP/min
Purkinje Fibers = 20-40 AP/min
41
Choose one:
| Depolarization is the (recovery / activation) within the myocardium.
activation
42
The pressure that must be exceeded before ejection of blood from ventricles can be defined as, ______________. What are those pressures for the aorta and pulmonary trunk, respectively?
afterload; aorta-80mmHg, pulmonary trunk-20mmHg
43
Which coronary vein drains the superior portion of the right ventricle and opens directly into the right atrium-bypassing the coronary sinus?
the anterior cardiac vein
44
What layer of tissue is tough, inelastic, and dense while also preventing the over-stretching the heart itself?
The fibrous pericardium.
45
What hormone is triggered and released from the impulses of accelerator nerves?
norepinephrine.
46
The movement of ions into a cell is __________.
| The movement of ions out of a cell is __________.
influx; efflux
47
A normal adult ventricle can hold ______ mL of blood before it is full.
130mL
48
In fetal cardiact anatomy, what structure allows blood that has made it into the right ventricle and pulmonary trunk to bypass the lungs ?
The ductus arteriousus
49
What type of fiber is "stair-step" in appearance and usually has one centrally located nucleus but may sometimes have two?
cardiac fibers
50
The serous pericardial layer is made up of what to sub-layers?
The parietal (cavity lining) layer; and the visceral (organ lining) layer
51
Into what heart structure does most of the deoxygenated blood from the coronary vessels drain?
the large vascular sinus
52
What type of fibers of the fibrous skeleton are between heart chambers and around heart valves?
collagen and elastic fibers
53
In Phase 2, the _______ phase, of action potential of contractile fibers, there is a slow influx of ______ balanced with an efflux of _____ ions. The influx of ____ initiates the activation of __________ and _________ causing the cell to contract.
plateau; Ca2+; K+; Ca2+; troponin and myosin
54
What are the series of grooves on the surface of the heart?
The sulci
55
The volume of blood ejected from the left ventricle (or the right ventricle) into the aorta (or the pulmonary trunk) per minute is defined as?
Cardiac Output (CO)
56
What special feature of the heart externally separates the atria from the ventricles?
the coronary sulcus
57
During atrial systole, what amounts are moved into the ventricle:
___ mL pours in by weight/volume alone
___ mL is forced in by atrial systole
___ mL is usually there from the previous cycle
45 / 25 / 60
58
From what heart structures does the right atrium receive the blood?
the superior vena cava, the infrerior vena cava, and the coronary sinus
59
When a ventricle contracts, the lumen size __________ thus increasing the pressure within the ventricle.
decreases
60
What is the resting heart rate of an infant?
120bpm
61
True or false: During ventricular systole the ventricles contract, the atriaventricular valves close and semilunar valves open.
True
62
True or False: The atria contracts AFTER the AV valve opens.
True.
63
Another action potential cannot occur normally during the action potential phases of contractile fibers. This period is referred to as what?
The absolute refractory period
64
During ventricular systole, the ventricular pressure rises to what pressure in the right and left ventricles, respectively:
Right: ____ mmHG
Left:____ mmHG
Right: 25-30 mm;
Left: 120 mmHG;
65
What is the role of the coronary sinus?
The coronary sinus returns coronary blood back into the right atrium.
66
Why is the contractility of ventricles not well controlled by parasympathetic impulses?
There are very few fibers that terminate in the ventricular muscle.
67
"If the left side pumps more blood than the right, the volume returning to the right ventricle increases. This increased end-diastolic volume (EDV) causes the right ventricle to contract more forcefully." - This is an example of what?
the Frank-Starling Law
68
In ECGs, the three waves are:
__ wave - _______ ______________
_ _ _ ______ - rapid _______ _______________
__ wave - __________ ________________
P wave - atrial depolarization
QRS complex - rapid ventricular depolarization
T wave - ventricular repolarization
69
What are the cone-shaped trabeculae carneae found in the ventricles?
the papillary muscles
70
There are two types of cardiac muscle fibers - name them and describe their roles.
Autorhythmic/excitatory/conductive fibers: these fibers initiate and conduct action potentials that help to control rhythmical beatings of the heart.
Atrial/ventricular muscle (contractile) fibers: require an action potential from conductive fibers in order to contract
71
Within the heart itself, the myocardium has its own network of blood vessels called ________ _________.
coronary circulation
72
During ventricular systole, the ventricular ejection of blood occurs when both _____________ valves are open.
semilunar valves
73
What hormone increases the conduction of action potentials through the SA/AV nodes and also increases Ca2+ entry into contractile fibers which increases contractility?
norepinephrine
74
What does the right coronary artery supply?
It supplies the small atrial branches and feeds the right atrium.
75
The fossa ovalis is a depression in the interatrial septum that is a remnant of the ______ ________.
foramen ovale
76
True or False: Although it is striated like skeletal muscle, it is cardiac muscle so therefore it is voluntary.
False; it is involuntary
77
Blood passes from the right ventricle into the pulmonary trunk through the ________ valve.
pulmonic (semi-lunar valve)
78
The fibrous pericardial layer of the pericardium is attaches and is continuous with what part of the body?
The central tendon of the diaphragm.
79
What is the formula to calculate cardiac output?
Cardiac output = stroke volume (mL/beat) x heart rate (beats/min)
80
While in motion, autonomic nerve impulses and hormones are released by the ________ system.
sympathetic
81
Choose one:
| Pacemaker potential is between the (highest / lowest) membrane potential (mV) and the threshold membrane potential (mV).
lowest
82
These receptors monitor the stretching of major arteries and veins caused by blood pressure flowing through them. There are important receptors of this type located in the aortic arch and the carotid arteries.
Baroreceptors (baro-pressure)
83
The ventricular myocardium receives action potential from what type of fibers in the conductive system of the heart?
Purkinje fibers
84
When the autonomic nervous system is STIMULATED, what hormones are released to increase contractility which, in turn, would increase stroke volume?
Epinephrine, norepinephrine, digitalis
85
What segment represents ventricular depolarization during the plateau phase (end of contraction)?
S-T segment
86
What does the "small cardiac vein" do?
Drains the portion of the right ventricle and atrium
87
What interval is the beginning of ventricular depolarization to the end of ventricular repolarization?
Q-T interval
88
Valves open and close in response to what?
A.) electrical charge of the septum
B.) pressure due to the weight/volume of blood in the chamber
C.) contractions of the ventricles
B.) Pressure due to the weight/volume of blood in the chamber
89
What structure branches from the proximal ascending aorta and encircle the heart?
the coronary artery
90
Vagal axons terminate in what areas of the heart?
in the SA node; AV node; and atrial myocardium
91
What feature externally separates the right and left ventricles?
The interventricular sulcus
92
Ventricular relaxation and filling can be defined simply as ___________.
diastole
93
When does most coronary blood flow occur?
During the diastolic phase of the ventricles
94
A greater preload, or stretch, on the cardiac muscle fibers prior to contraction will ____________ the force of the contraction?
A.) increase
B.) decrease
C.) equalize
D.) not effect
increase; much like drawing back the bowstring of a bow.
95
What nerves originate in the thoracic region of the spinal cord and extend out to the SA node, AV node, and most portions of the myocardium?
cardiac accelerator nerves
96
What cavity is between the parietal and visceral layers of the serous pericardium?
the pericardial cavity
97
What supplies the heart walls with blood?
The coronary arteries receive blood from the proximal ascending aorta.
98
True or False: When atrial systole ends, ventricular diastole begins.
False; When atrial systole ends, ventricular diastole ends.
99
At what pressure, approximately, does the aortic valve close?
100mmHg
100
In ECGs, what occurs during the QRS complex?
rapid ventricular depolarization
101
In ECGs, what occurs during the T wave?
ventricular repolarization
102
True or False: With regard to heart contraction, the electricity, or message, starts in the contractile fibers of the heart but ends in the conductive fibers.
False; starts in the conductive-ends in the contractile
103
What cation(s) are involved in Phase 0-4 with regard to the action potential of contractile fiber?
```
Phase 0:
Phase 1:
Phase 2:
Phase 3:
Phase 4:
```
Phase 0: Na+
Phase 1: Na+ influx/shuts off; K+ efflux leaks; Ca2+ influx
Phase 2: Ca2+ slow influx; K+ efflux leaks;
Phase 3: K+ voltage gated channels open for mass efflux
Phase 4: rapid efflux of K+ complete
104
The enlargement of the heart can occur from a pathological and physiological response. What is the proper term for the "enlargement"?
cardiomegaly
105
What are the three main factors that regulate the stroke volume and ensure the left and right ventricles pump the same amount?
Preload, contractility, afterload
106
True or False: The depolarization of the atria causes atrial systole, seen as the P wave on ECG, while at the same time, the ventricles are in ventricular diastole.
True
107
What is the pathological process of the valve cusps flowing in the opposite direction?
valve eversion
108
The aortic arch gives rise to what 5 arteries?
the brachiocephalic, left common carotid and the left subclavian arteries and the right subclavian and right common carotid (branched off of the brachiocephalic)
109
What does the "great cardiac vein" do?
Drains portion of both ventricles and the left atrium
110
What portion of the heart does the internodal pathway exist?
the right atria
111
What "law of the heart" refers to the equalizing of the output of the right and left ventricles?
Frank-Starling Law
112
Ventricular contraction and ejection can be defined simply as ____________.
systole
113
Once the ductus arteriosus closes and becomes the ligamentum arteriousium, what purpose does it serve as a structure for the heart?
It is a ligament of stability at this point.
114
What is the formula for heart rate?
Beats per minute
115
The Bachmann's Bundle comes off of the ________ internodal pathway and pierces the _______ _______ to send impulses to the _____ ________?
anterior; interarterial septum; left atrium
116
The parietal layer of the serous pericardium is fused to what?
The fibrous pericardium
117
Pressure in the left ventricle rises to 120mmHg before ejecting approximately ____ mL into the aorta.
70mL
118
The circumflex lies in the ________ ________ and supplies the high lateral wall of the ________ ventricle and _______ atrium.
coronary sulcus; left; left
119
Stroke Volume = _____ - ______
SV = End diastolic volume - end systolic volume
120
Which cation blocks the inflow of calcium ions during AP (action potential)?
Na+
121
What are the two layers that make up the pericardium (pericardial sac).
The fibrous pericardial layer; the serous pericardial layer.
122
True or False: Trabeculae carneae are the raised bundles of cardiac muscle fibers found in the atria(s).
False; they are found in the ventricles
123
With regard to heart sounds, what causes the sound of the S2?
In S2, the blood turbulence caused by the closure of the SL valves at the beginning of ventricular diastole.
124
True or false: When the ventricles relax, the papillary muscles relax therefore the chordae tendineae are taut.
False; the chordae tendineae are relaxed as well
125
In Phase 1 of action potential of contractile fibers, the cell has reached peak positive charge by the rapid influx of ___ slows and completely shuts off. There is ____ "leaking" out of the cell.
Na+ ; K+
126
True or Flase: The conductive system is a nerve tract.
False; it is controlled by charges (+/-) being moved across cell membranes of both types of heart tissue
127
What type of valves are involved in the S2 heart sound? Name the type and nomenclature.
The semi-lunar valves - aortic and pulmonary.
128
This location, within the conductive system, is the only site where action potentials propagate from atria to ventricles in the normal heart. What is the described location?
The Bundle of His
129
What receptor sends nerve impulses at an increased frequency to the cardiovascular center and can become a major stimulus for quick rise in heart rate?
proprioreceptor
130
True or False: The cardiovascular center can direct increases and decreases of nerve impulses in BOTH parasympathetic and sympathetic branches of the ANS.
True.
131
What causes ventricular systole?
The depolarization of the ventricles
132
For the ejection fraction, anything greater than what percentage is considered "normal"?
60%
133
Choose one:
| Action potential is between the threshold membrane potential (mV) and the (highest / lowest) membrane potential (mV).
highest
134
Which system predominates during rest?
Parasympathetic or sympathetic? Why?
Parasympathetic predominates because of the release of acetylcholine (Ach)
135
The fibrous skeleton provides ________ support, and prevents valves from be overly ______________, while anchoring the ____________, and acting as an electrical ___________ between the atria and ventricles.
structural; distended (stretched); myocardium; insulator
136
In Phase 4 of the action potential of contractile fibers, the membrane potential is considered _______, which is achieved once the rapid efflux of K+ is complete. At this point the concentration of the K+ is ______ in both the intra- and extra-cellular fluid.
resting; equal
137
Do males or females have a "slightly" higher resting heart rate?
females
138
If external/internal factors increase the stroke volume or heart rate, the cardiac output will ___________.
A.) decrease slightly
B.) increase
C.) remain the same
B.) increase
139
The forcefulness of the contraction of the heart can be defined as, ____________.
contractility
140
What interval represents the conduction time from the beginning of atrial excitation to the beginning of the ventricular excitation?
P-Q interval
141
The base of the heart is formed MOSTLY by the ___________ and a small contribution of the ___________.
left atrium; right atrium
142
What effect does a positive inotrope have on the stroke volume of the heart?
A positive inotrope increases the contractility by increasing stroke volume.
143
The left and right coronary artery branch from what portion of this "great vessel"?
the proximal ascending aorta
144
The apex of the heart is formed by ___________ of the left ventricle and rests on the __________.
inferolateral region; diaphragm
145
How many phases are in the action potential of contractile fibers?
5; Phase 0-4
146
What is the term for the amount of blood that is left in either ventricle after the diastolic phase?
end-diastolic volume
147
What is the effect of a negative inotrope?
It decreases the contractility.
148
Which heart sound makes the "LUBB"? Which makes the "DUPP"?
S1 - LUBB; S2 - DUPP
149
A change in cell membrane potential that makes it less negative (or more postive) is defined as?
Depolarization
150
What is the dividing line in the right atrium that transitions smooth surface to the pectinate muscle?
the crista terminalis
151
What receptors monitor chemical changes in blood?
Chemoreceptors
152
What is the membrane that surrounds and protects the heart and the beginning portion of the great vessels?
The pericardium (pericardial sac)
153
The autonomic regulation of heart rate originates in the cardiovascular center of the medulla oblongata. What does this receive input from?
sensory receptors, limbic system, cerebral coretex.
154
True or False: Action potentials propagate through the heart in the following sequence:
Sinoatrial node --> internodal tracts/Bachmann's Bundle (left atrium)---> atriventricular (AV) node --> AV bundle (Bundle of His)--> AV bundle branches (left/right) --> Purkinje fibers
True
155
In Phase 1 of action potential of contractile fibers, there is a brief ___________ of the cell membrane potential. The transition to Phase 2 occurs once the slow-voltage gated _____ channels open and allow ____ influx into the cell.
repolarization; Ca2+; Ca2+
156
Fill in the blank & choose one:
In conductive fibers, there is a slow influx of ____ that begins the next cycles prepotential. A rapid influx of _____ creates a (de/re)polarization moving the membrane potential to a more positive voltage. Once the peak action potential is met, the rapid outflux of ______ creates a (de/re)polarization.
Na+; Ca2+; depolarization; K+; repolarization;
157
The decrease in action potential of the AV node allows for the _______ to empty blood into the ________.
atria; ventricles
158
What do these two factors determine?
1. The duration of the ventricular diastole; if shorter, less blood is able to fill the ventricle.
2. Venous return-volume of blood returning to the right ventricle (if ventricular diastole is shorter, less blood is pushed to systemic, meaning less blood is returning to the right side of the heart).
These two factors determine end-diastolic volume (EDV).
159
A change in the cell membrane potential that makes it more negative (or less positive) is defined as?
Polarization
160
Pressure in the right ventricle rises to 25-30mmHg before ejecting approximately ____ mL into the pulmonary trunk.
70mL
161
In Phase 3, the ___________ phase, of action potential of contractile fibers, voltage gated _____ channels open allowing a rapid and mass efflux from the cell. The efflux of the ____ cation causes rapid repolarization. This phase includes the completion of muscle fiber contraction as well as ____________ (relaxation) .
repolarization; K+; K+; repolarization
162
True or False: Auricles have the same basic layers of the heart and increases the collecting and pumping capacity of the atria.
True
163
What does the "base" of the heart consist of, with regard to veins and arteries?
4 pulmonary veins; 2 pulmonary arteries.
164
What portion of the heart contains the electrical tract that sends the message to the left atria to contract at the same time as the right atria?
The interartrial septum
165
True or false? A individual's cardiac reserve is the difference between their maximum cardiac output and the resting cardiac output.
True.
166
In ECGs, what occurs during the P wave?
atrial depolarization
167
The rupturing/elongation of the chordae tendineae allowing the atriaventricular valves to evert into the atria can be described as what?
valve eversion
168
The right side of the heart leads to which type of closed circuit circulation?
pulmonary circulation
169
The heart beat sounds during auscultation are audible due to the blood rebounding off of what?
Valve leaflets
170
At rest, the stroke volume of the heart is between what percentage of the end-diastolic volume (EDV)?
50-60%
171
What hormones influence cardiacmuscle and heart rate?
Epinephrine; norepinephrine; thyroid hormones
172
What are the regions of thickenings of the sarcolemma, or plasma membrane, of a cardiac muscle fiber that connect neighboring fibers?
intercalated discs
173
INPUT TO THE CARDIOVASCULAR CENTER: Proprioreceptors, chemoreceptors, and baroreceptors monitor what, respectively?
movements; blood chemistry; blood pressure
174
Within the right atrium, the anterior wall is rough because of the ______ ______. The posterior wall is smooth with a _____ ______ border between the smooth and rough surfaces and the ________ ________ separates the left and right atria.
crista terminalis; pectinate muscles; interatrial septum
175
Which two cations in an elevated concentration decrease heart rate and contractility?
Na+ and K+
176
Which cation blocks the generation of AP while also decreasing HR and contractility?
K+
177
The volume of blood ejected by the ventricle during each contraction is defined as?
Stroke Volume (SV)
178
Anastomoses provide alternate routes called _________ __________.
collateral circulation
179
The change in electrical potential associated with the passage of an impulse along/across the membrane of a muscle cell or neuron can be defined as _______ _________.
action potentials
180
Parasympathetic impulses reach the heart by which nerve pathways?
Via the left and right vagus nerves
181
What is the dense connective tissue throughout the heart muscle tissue that acts as an electric insulator between the atrial and ventricular muscle fibers?
Fibrous skeleton
182
Stroke volume (SV) can be defined as the volume ejected per ____ from each _________.
beat; ventricle
183
What two valves are atrioventricular valves?
The mitral (bicuspid) and the tricuspid valve.
184
The connection of two or more arteries that supply a specific region are referred to as _____________.
anastomoses
185
The intracellular space has a more _________ charge.
negative
186
The S3 heart sound is caused by what?
The blood turbulence during rapid ventricular filling.
187
What does the "middle cardiac vein" do?
Drains the posterior aspect of both ventricles
188
In action potential of contractile fibers, Phase 0 is the _____________ of the cell membrane potential.
depolarization
189
What is another name for the coronary sulcus?
the atrioventricular sulcus (AV sulcus)
190
Volume remaining in each ventricle at the end of ventricular systole is now known as the ____-______ _______.
End-systolic volume
191
The heart wall is made up of what three regions?
The epicardium, the myocardium and the endocardium
192
What diagram is a picture of "one heartbeat" and is focused from the left side of the heart? It also explains (L) atrial and ventricle pressure, aortic pressure, ECG, and (L) ventricle volume.
Wiggers Diagram
193
What are the two functions of the conductive/autorhythmic fibers?
To be a pacemaker and set the rhythm of electrical excitation that leads to contraction; the cardiac conduction system ensures the heart chambers become stimulated to contract in a coordinated manner
194
What are two conditions that can cause increased afterload?
Hypertension, atherosclerosis
195
The extracellular space has a more ___________ charge.
positive
196
What protects the major coronary and cardiac vessels that feed the heart layers?
the adipose tissue of the epicardium
197
What type of valves are involved in the S1 heart sound? Name the type and nomenclature.
The atrioventricular valves - tricuspid and mitral (bicuspid).
198
What structure is described as the "natural pacemaker"?
the sinoatrial (SA) node
199
The degree of stretch the heart has before contraction can be defined as, __________.
preload
200
What is defined as “the strength of a contraction at ANY given preload”?
Contractility
201
Which of these choices causes the semilunar valves to open?
A.) rise in electricity
B.) continued contraction in the ventricle that causes pressure to rise
C.) action potentials
D.) papillary muscles
B.) continued contraction in the ventricle that causes pressure to rise
202
What heart layer constitutes 95% of the heart wall?
The myocardium
203
In fetal cardiac anatomy, the ______ __________ is the OPENING through the atrial septum.
Foramen ovale - not fossa ovalis because it is OPEN
204
What layer of the heart is responsible for the pumping action of the heart?
The myocardium
205
At what voltages are the intracellular and extracellular space, respectively?
-90mV; +10mV or even -10mV
206
What is the only "normal" pathway for electricity to get from the atria into the ventricles?
Through the interatrial and interventricular septum
207
Impulses are formed in the primary pacemaker that can defined as the ________ _____.
Sinoatrial node (SA node)
208
What reduces the friction between the layers of the serous pericardium?
pericardial fluid
209
What "usually" lies posterior to the left 5th intercostal space in adults?
The apex of the heart.
210
What two special features of the heart can be seen on BOTH the anterior and posterior surface?
the atrioventricular sulcus and the interventricular sulcus
211
In general, the body attempts to normalize which particular potentials across cellular membranes?
electrical and chemical potentials
212
Choose the correct answer:
The left coronary artery passes (superior / inferior) to the left auricle and divides into the anterior interventricular branch, also called the left anterior descending (LAD) and the circumflex.
inferior
213
True or False: The Bundle of His is embedded in fibrous skeleton of the heart.
True.
214
Intercalated discs contain what two structures?
| What are their roles?
desmosomes - hold fibers together physically
| gap junctions - allow action potentials to conduct from one muscle fiber to its neighbor
215
In what phase of contractile fiber action potential does the muscle fiber begin to contract?
Phase 2
216
In Phase 0 of action potential of contractile fibers, there is a rapid influx of ____ which makes the cell positive.
Na+
217
What are four ion channels in cellular membranes?
Leakage channels; voltage gated; mechanically gated; ligand gated
218
In the regulation of stroke volume, what is the pressure (mmHg) that must be overcome before the semilunar valve can open in the pulmonary trunk and aorta, respectively?
In the afterload it is 20mmHg for the pulmonary trunk; 80mmHg for the aorta.
219
In regards to action potential velocities, which fiber velocity is the slowest, intermediate, fastest?
slowest: SA/AV
intermediate: atria/ventricular contractile fibers
fastest: purkinje fibers
220
In Phase 2 of action potential of contractile fibers, the influx of Ca2+ intiates the activation of what two proteins within the myocardium?
troponin and myosin
221
What does the left coronary artery divide into?
the LAD and the circumflex
222
Fill in the blank:
With regard to the conductive system, the right and left bundle branches extend through the ___________ ______ toward the ______ of the heart.
interventricular septum; apex
223
What type of conductive fibers receive the action potential and rapidly conducts it, beginning at the apex, upwards to the remainder of the ventricular myocardium?
Purkinje fibers
224
What are the three regions (cusps) of the tricuspid valve?
anterior, septal, posterior cusps
225
The interventricular septum is thought to be mostly made up of the _____ _________ due to its wall size.
left ventricle
226
While at rest, what compound/neurotransmitter is released by the parasympathetic system to slow the SA node?
acetylcholine
