Unit One Flashcards
1
Q
What is the supply and demand concept of the heart
A
Cells demand O2 and nutrients, the CV system supply blood to cells
2
Q
Blood flow occurs when what exists
A
Change in pressure, one pressure exceeds the other
3
Q
What does every cell need for survival
A
Oxygen, nutrients, removal of CO2 and metabolic waste, optimal temperature
4
Q
Oxygen is needed by the cell for what
A
Aerobic respiration
5
Q
Nutrients are needed by the cell for what
A
Energy, building blocks, etc
6
Q
Carbon dioxide retention causes
A
Acidosis leading to confusion, come, arrhythmia, muscle weakness, GI disturbances
7
Q
Urea and other metabolic wastes left in blood causes
A
Anorexia, lethary, decreased mental acuity and coma, nausea, vomiting, bone pain, itch, SOB, seizures and death
8
Q
Why do our cells need optimal temperature
A
Function at a narrow temperature range
9
Q
Can demands be met by just diffusion from the outside of the body
A
No, diffusion is too slow over large distances
10
Q
It takes how long for O2 to diffuse 100 micrometers
A
5 seconds
11
Q
How long for O2 to diffuse 1 cm
A
14 hours
12
Q
Main purpose of the cardiovascular system
A
Provide a sufficiently fast mechanism of delivery and removal of gasses, nutrients, and wastes by blood flow
13
Q
Diffusion is important at what levels of the body
A
Capillaries, interstitial fluid and cell membranes
14
Q
What is a blood conditioner organ
A
Any organ that changes the composition of the blood for the benefit of the rest of the body
15
Q
What organs are blood conditioner organs
A
Lungs, kidneys, GI tract and skin
16
Q
What two things do all blood conditioner organs have in common
A
Blood flow in excess of their basic metabolic needs, can tolerate substantial drops in blood flow for a short period of time
17
Q
What are some organs that are important but not blood conditioners
A
Brain, muscle and heart
18
Q
What are the characteristics of brain, muscle and heart not being blood conditioners
A
Blood flow is regulated to be at or just above metabolic need, loss of blood flow to these organs has more dramatic effect
19
Q
The systemic circuit goes from where to where
A
Left ventricle, body, right atrium
20
Q
The pulmonary circuit goes from where to where
A
Right ventricle, lungs to left atrium
21
Q
The systemic and pulmonary circuit are parallel or series
A
Series
22
Q
Function of systemic circuit
A
Supplies many organs, trunk, head and limbs in parallel circulation
23
Q
Is the systemic circuit parallel or series
A
Parallel
24
Q
What are the three places within the systemic circuit that has serial blood supply
A
Liver, kidney and anterior pituitary
25
Advantage of parallel circuit
If something is blocked then there are other ways around to have area receive blood, simultaneous blood supply
26
What is the basic flow equation
= change in pressure/ resistance to flow
27
Basic flow equation AKA
Ohm’s law
28
Flow (volume per unit time) represented by what
Q
29
What is the equation for resistance
8Ln/(pi)r^4
30
What is cardiac output
Blood from the heart
31
Flow (Q) is also called
Cardiac output
32
Normal cardiac output is
5 L/min
33
What is the source of blood flow
Heart
34
What must the heart do in order for flow to occur
Arterial pressure greater than venous pressure
35
How does resistance of blood flow occur
Frictions,
36
What is the main determinant of resistance
Blood vessel radius especially in arteriole
37
Why is the blood vessel radius in arterioles the most important
Radius is regulated the most here
38
The left ventricle has an average pressure of what
100 mmHg
39
Radius changes within vessels due to
Smooth muscle, dilation and constriction
40
How does the venous system work with pressure and bringing blood to heart
Pressure still builds up but not greater than arterial pressure and veins contain valves
41
Because blood flows along the path of least resistance, organs with ???? Resistance receives the ???? Flow.
Low, most
42
Constriction in vessels cause
Diversion to another place
43
What are the requirements for effective heart function
Synchronized contraction of heart muscle, valves open fully, no leaky valves, contractions adequately strong, ventricles fill adequately
44
What are the parts of the left heart
Left atrium, bicuspid/ mitral valve, left ventricle and aortic valve, pulmonary veins
45
Function of left heart
Receives blood from lungs and pumps blood to body
46
Parts of the right heart
IVC, SVC, coronary sinus, right atrium, tricuspid valve, right ventricle, pulmonary valve
47
Functions of the right heart
Receives blood from the body, pumps blood to the lungs
48
Describe cardiac cells
Single centrally located nucleus, branched fibers, striated, intercalated discs
49
What connects the adjacent cells in the cardiac muscle
Gap junctions
50
Gap junctions form what between cells
Electrical synapses
51
Atrial and ventricular syncytia are separated by what
Fibrous septum
52
The fibrous septum surrounds what
Openings of the two AV valves.
53
What are not propagated through the fibrous septum
Action potentials
54
Aka of hyperpolarization
Undershoot
55
Is a stimulus needed for cardiac cells to have an AP
No
56
Cardiac muscle cells exhibit what two properties
Automaticity and rhythmicity
57
What is automaticity
Cells generate their own action potentials without external stimuli from nerves or chemicals
58
What is rhythmicity
Action potentials repeat at regular intervals
59
What cardiac muscle tissue has the fastest inherent firing rate
SA node
60
SA node AKA
Pacemaker
61
SA node connects with conduction system and what to control the rate of the whole heart
Intercalated discs
62
SA node embedded where
Wall of RA
63
Conduction system is made of
Specialized cardiac muscle cells
64
Amount of actin and myosin in the conduction system
Very little and contracts very weakly
65
Conduction system coordinates what
Timing of atrial and ventricular contractions
66
Communication between the atria and ventricles is done through
Bundle of His
67
Function of internodal tract
Spread AP to AV node, spread AP into both atria, help to spread AP throughout cells
68
What does the signal move slowly through AV node
Allow for ventricle to fill with blood
69
How many phases of the heart
Phase 0 through 4
70
What is phase 0 aka
Depolarization
71
What occurs during phase 0
Opening of fast V gated Na+ channels
72
Aka of phase 1
Initial spike
73
What occurs during phase 1
V gated Na+ channels inactive
74
Phase 2 aka
Plateau
75
What occurs during phase 2
V gated slow Ca2+ channels open and decrease in K+ permeability also occurs
76
Phase 3 aka
Repolarization
77
What occurs during phase 3
V gated Ca2+ channels close and V gated K+ channels open
78
Aka of phase 4
Resting membrane potential
79
What occurs during phase 4
Active transport of Na+, K+ and Ca2+
80
Describe the SR of cardiac cells
Not well developed
81
Describe T tubules of cardiac cells
5x bigger in diameter
82
Cardiac cells greatly depend on what for initiation and strength of contraction
Extracellular Ca2+ for initiation and strength of contraction
83
Relaxation of heart requires what
Pumping Ca2+ back into SR and out of the cell
84
The duration of cardiac contraction is about equal to
Duration of the cardiac action potential
85
Why is the cardiac contraction equal to duration of AP
Want the contraction long enough to empty atrium or ventricle, helps to not spend extra energy
86
Definition of cardiac cycle
All events occurring in the heart from the beginning of one heart beat to the beginning of the next
87
Definition of pressure
The magnitude of the force F exerted by a fluid on the surface, divided by the surface area A
88
Fluid moves from an area of
High pressure to an area of low pressure
89
The chambers of the heart alternate between periods of
Systole and diastole
90
Systole aka
Contraction
91
Purpose of systole
Generate pressure to perform the work of moving blood
92
Diastole aka
Relaxation
93
Purpose of diastole
Release pressure so that the heart chamber can fill with blood
94
The cardiac cycle components relating to pressure changes are recorded from the
Left atrium and ventricle
95
The right cardiac cycle looks essentially the same, except the pressures are about what compared to the left
1/6
96
What are the primer pumps
Atria
97
How much of the blood in the atria moves to the ventricles before atrial systole
80%
98
How much of the blood moves to the ventricles from the atria during atrial systole
20%
99
What happens if the atria fail to function
Lower cardiac output, clot formation
100
When atria contract what relaxes
Ventricles
101
What are the three atrial pressure curves
A, C and V curve
102
What occurs during the A curve
Increase in pressure due to contraction (atrial systole)
103
What occurs during the C curve
Fluctuation in pressure due to AV valve closure
104
What occurs during the V curve
Increase in pressure as atrium fills
105
What happens to pressure in ventricle during diastole
Decreases
106
What occurs during isovolumic relaxation
Pressure in ventricle decreases, valve can now close, diastole
107
Ventricle diastole has how many phases
Three, early, middle and late
108
What occurs to ventricle during early diastole
Blood enters ventricle, rapid inflow
109
What occurs to ventricle during middle diastole
Diastasis, reduced inflow
110
What occurs to ventricle during late diastole
Last 20% of blood comes in, atrial systole
111
What is isovolumic contraction
Pressure in ventricle not greater than pressure on other side of valve
112
Ventricular systole has how many phases
2, early and late
113
What occurs in ventricle during early systole
Rapid ejection
114
What occurs to ventricle during late systole
Reduced ejection
115
Does end systole in ventricle completely empty all blood
No
116
What is end diastolic volume
Amount of blood volume in ventricle at end of diastole
117
What is end systolic volume
Amount of blood volume in ventricle at end of systole
118
What is stroke volume
Amount of blood ventricle ejects after one contraction
119
Equation for stroke volume
End diastolic volume - end systolic volume
120
What is ejection fraction
Amount of blood percent squeezed out at end of contraction
121
Equation for ejection fraction
Strok volume/ end diastolic volume x 100
122
Ejection fraction should be around what percent
60%
123
Equation for cardiac output
Stroke volume x heart rate
124
During exercise, how to increase cardiac output
Increase heart rate or increase stroke volume or both
125
Why does HR at 180 stop increasing CO
Not having enough time for diastole, or need ventricles to fill
126
When do AV valve close
Ventricular pressure greater than atrial pressure
127
AV valves open when
Atrial pressure greater than ventricular pressure
128
What prevents prolapse into the atria of AV valve
Chordae tendineae and papillary muscles
129
Semilunar valves open when
Ventricular pressure greater than aortic/ pulmonic pressure
130
Semilunar valves close when
Aortic/ pulmonic pressure greater than ventricular pressure
131
What are the three components of the aortic pressure curve
During systole, incisura, and during diastole
132
During systole, the aortic pressure rises with
Ventricular contraction, 120 mmHg
133
Aka of incisura
Dicrotic notch
134
What occurs during incisura
Pressure fluctuation due to closing of the aortic valve
135
During diastole, aortic pressure falls due to
Elastic recoil of the aorta to 80 mmHg
136
Heart sounds can be recorded using a
Phonocardiogram
137
How many heart sounds are there
4, S1-S4
138
What is S1 heart sound
First heart sound, closure of AV valves, “lib”, beginning of systole
139
What is S2 heart sound
Closure of the semilunar valve, “dub”, transition into diastole
140
what is the S3 heart sound
Due to filling of ventricles in mid diastole
141
Can you hear S4
No, only recorded using phonocardiograms
142
What occurs during S4 heart sound
Due to atrial systole
143
Where is the atrial repolarization
Hidden behind QRS
144
What are the three components of the EKG
P wave, QRS complex, T wave
145
P wave initiated by
SA node
146
P wave represents
Atrial depolarization
147
P wave precedes
Atrial systole
148
QRS complex represents
Ventricular depolarization
149
QRS complex precedes
Ventricular systole
150
T wave represents
Ventricular repolarization
151
T wave precedes
Ventricular diastole
152
Are there any measuring forces in EKG
No just electricity
153
What is work output of the heart
The amount of energy that the heart converts to work during each heartbeat
154
What are the two forms of work the heart does
External work and kinetic energy of blood flow
155
What is the external work the heart does
Move blood from veins to arteries (most of the work done)
156
What is the kinetic energy of blood flow
Accelerates blood into the great arteries (minor fraction of heart work)
157
What are the four factors that influence the strength of the contraction
Preload, afterload, contractility, and heart rate
158
What is preload
End diastolic pressure in the ventricle, or length muscle is stretched before contraction, “filling”
159
What is afterload
Forces against which cardiac muscle must overcome (arterial pressure, resistance to flow)
160
Contractility is what type of state
Ionotropic state
161
Contractility is a modification of
Strength independent of loading changes
162
Contractility occurs where
Cellular level
163
Contractility includes effects of
autonomic nervous system and hormones
164
What indirectly increases contractility
Heart rate
165
Increase heart rate does what to Ca2+
Accumulate faster than it is removed
166
What is intrinsic regulation of the heart
Frank starlings mechanism
167
What is frank starlings mechanism
Greater the heart muscle is stretched during filing, greater the force of contraction and the greater the quantity of blood pumped into the aorta
168
How is there a greater force of contraction on a cellular level in heart
Cardiac muscles sarcomeres are short and resist stretch, increase in length increases number of functional cross bridges between actin and myosin therefore creating greater force of contraction
169
Right atrial stretch increase heart rate by
10 - 20%
170
Frank starlings law of heart says venous return equals what
Cardiac output
171
Extrinsic regulation of heart is innervation of the heart via
Autonomic nervous system
172
Sympathetic does what to heart
Increases heart rate, increases force of contraction
173
Parasympathetic does what to heart
Decreases heart rate, weakly decreases force of contraction
174
What are the three other influences on heart function
Potassium ions, calcium ions and temperature
175
How does potassium ion influence heart function
Hyperkalemia causes weak contractions, slows heart rate, abnormal rhythms and potentially death
176
How does calcium ions influences heart function
Hypercalcemia causes spastic contractions
177
How does temperature influence heart function
Fever causes and increase in heart rate
178
Location of SA node
Superior posterolateral right atrium
179
How is the SA node self excited and has inherent rhythmicity
Sodium leak, higher resting membrane potential, lower threshold
180
The SA node connects to the
Atrial muscle and internodal fibers
181
Internodal fibers receives action potential from
SA node
182
Internodal fibers connects to what node
AV node
183
Why does AV node delay action potential
Low number of gap junctions, give atria time to contract before ventricles contract
184
AV node slows velocity or rate
Slows velocity
185
AV node located where
Posterior right atrium
186
The purkinje fibers lead from the
AV node, through the AV bundle through the left and right bundle branches then throughout the ventricular muscle
187
Does the purkinje system have a very fast or slow conduction velocity
Fast
188
List the conduction system parts in order of fastest to slowest inherent firing rate
SA node, AV node, purkinje system
189
What are the two electrodes to record voltage
Negative (reference) and positive (recording)
190
A signal is detected by the oscilloscope when there is an
Electrical difference between the two electrodes
191
An action potential is
Electrical events in a cell
192
Electrocardiogram has electrodes placed
Outside of cell and has mass effect in bundle of cells
193
EKG notices what
Deflection from zero lines due to depolarizations and repolarizations
194
Action potential recordings are Monophasic or biphasic
Monophasic
195
What is Monophasic
Only show amplitude of voltage changes as recorded at a point in a cell
196
EKG recordings are Monophasic or biphasic
Biphasic
197
Biphasic is
Records both amplitude and direction of waves of voltage changes through heart muscle
198
Biphasic is what type of quantity
Vector
199
PR interval is how long
.16 sec
200
P R interval goes from what to what
SA node to AV node
201
QT interval shows
Electrical events in ventricle
202
The isoelectric line aka
Zero line
203
Electrodes detect what
Waves of depolarization and repolarization throughout the heart tissue
204
What is an electrode
Physical wired from machine to skin
205
What is a lead
Set of electrodes used to make a recording
206
If you have 10 electrodes how many leads
12
207
The 12 lead EKG has what three lead groups
3 standard bipolar limb leads, 3 augmented unipolar limb leads, 6 precordial chest leads
208
Why can you have multiple negative electrodes but have one positive
Positive electrode gives direction it is heading toward
209
What are the standard bipolar limb leads
Lead 1,2,3
210
Lead one positive lead goes where
Left shoulder/ wrist
211
Lead one negative lead goes where
Right shoulder/ wrist
212
Lead two positive lead goes where
Left ankle
213
Lead two negative lead goes where
Right shoulder/ wrist
214
Lead three positive lead goes where
Left ankle
215
Lead three negative lead goes where
Left shoulder/ wrist
216
What is einthoven’s triangle
Group of leads that form a triangle
217
What is the electrode that is placed on the right ankle
Ground electrode
218
What is einthovens law
2 = 1 + 3, in regards to the amplitude of the R wave
219
What are the leads in the augmented unipolar limb leads
AVR, aVL, aVF
220
Positive lead of aVR
Right wrist
221
Negative lead of aVR
Left wrist and left ankle
222
Positive lead of aVL
Left wrist
223
Negative lead for aVL
Right wrist and right ankle
224
Positive lead for aVF
Left ankle
225
Negative lead for aVF
Left wrist and right wrist
226
AVR should show what type of deflection
Negative due to going from left to right
227
What are the precordial leads
V1 - V6
228
V1 goes where
4 ICS to the right of sternum
229
V2 goes where
4 ICS to the left of sternum
230
V3 goes where
Between V2 and V4
231
V4 goes where
5 ICS, Left mid clavicular line
232
V5 should go where
5 ICS, left anterior axillary line
233
V6 should go where
5 ICS, left mid axillary line
234
What is the negative electrode in the precordial chest leads
Machine is used as reference point
235
What is the mean vector
Average of all vectors
236
Since atrial repolarization is not seen on EKG, the wave is actually called
atrial T
237
The Q wave represents
Septal activation
238
The R peak (most significant) represents
Apical activation
239
The R wave return represents
Left ventricular activation
240
The S wave represents
Left left ventricular activation
241
The pattern of ventricular repolarization begins from
Apex towards the base of the heart
242
What explains why the T wave is positive (lead 2)
Due to the pattern starting at apex then goes to base
243
What is the U wave
Wave on ECG that is sometimes seen
244
What causes U wave
Delayed replarization of purkinje fibers, prolonged repolarization of mid-myocardial M cells, after potentials resulting from mechanical forces in ventricular wall, repolarization of the papillary muscle
245
Purpose of hexaxial reference system
Used to determine the vector of depolarization through the heart
246
What is normal axis
0 to 90 degrees
247
What is left axis deviation
QRS axis of 0 to -90 degrees
248
What is right axis deviation
QRS axis of 90 to 180 degrees
249
What is extreme axis
-90 to -180 degrees
250
What is the average QRS axis
59 degrees
251
To plot the QRS axis based on limb lead what is required
Use of any two of the six limb leads
252
How to plot QRS axis
Take two leads and plot direction and magnitude, draw right angles, where they intersect is the axis of ventricular depolarization
253
QRS axis can be estimated by comparing what
The size of the QRS complexes of all six limb leads
254
What can cause left axis deviation
Short stock build, obesity, LV hypertrophy and left bundle branch block
255
What can cause LV hypertrophy
Hypertension, aortic valve stenosis, aortic valve regurgitation
256
What causes right axis deviation
Tall, long waist, lean build, RV hypertrophy, right bundle branch block
257
What causes RV hypertrophy
Pulmonary valve stenosis/ regurgitation, interventricular septal defect, tetralogy fallot
258
What is an interventricular septal defect
Still has hole from embryonic development, blood enters from left to right ventricle
259
What is tetralogy fallot
Interventricular septal defect, over riding aorta, pulmonary stenosis, right ventricular hypertrophy
260
Normal QRS voltage of sum of 1, 2, 3 should equal
2-4 mV
261
Individually leads 1, 2, or 3 should be was QRS voltage
.5 - 2 mV
262
Increased voltage of QRS is caused by what
Hypertrophy
263
Decreased voltage of QRS is caused by
Damaged heart muscle
264
QRS usually last for how long
.04 to .11 sec
265
If prolonged QRS time occurs, it is due to
Bundle branch block or hypertrophy
266
Current of injury is shown where EKG
ST segment
267
Current injury is what
Acute damaged heart muscle (MI) does not repolarize normally and therefore becomes a source of current
268
What is tachycardia
Resting heart rate faster than 110 bpm
269
Tachycardia caused by
Fever, certain toxins, SNS activity
270
What is bradycardia
Resting heart rate slower than 60 bpm
271
Reason for bradycardia
Athlete, vagal stimulation
272
Is sinus arrhythmia a normal variant
Yes
273
Sinus arrhythmia is due to
Respiratory center in medulla exciting nearby vasomotor center
274
Sinus arrhythmia can occur when heart rate increases with
Deep inspiration
275
Conduction blocks can be due to
Some part of heart sustained damage
276
What are the conduction blocks
SA block and AV blocks
277
How to determine SA block
P wave missing, slower HR
278
What are the different types of AV blocks
1st, 2nd and 3rd degree
279
1st degree AV blood shows what
P to R interval long, delayed QRS
280
2nd degree AV block looks like
Dropped beat, ventricles don’t have electrical activity, skipped beats
281
3rd degree AV blocks look like what
AV node creates own pace, SA node communications with AV node is not happening
282
Incomplete intraventricular block has what
Electrical alternans
283
What are electrical alternans
Alternating strength signals, not effective repolarization causing weak signal
284
Premature contractions are what
Contraction of the heart before the time they are normally expected
285
Aka of premature contractions
Extrasystole and ectopic beat
286
Premature contractions can occur in what part of heart
Atrial and ventricular
287
A fib or V fib triggered by
Electrical shock, ischemia, dilated hearts, high potassium or tachycardia
288
What occurs during atrial flutter
A single large wave that goes around the atria
