Physiology Flashcards
1
Q
Three pressures in the CV system?
A
- Driving (difference between two points)
- Hydrostatic (P of gravity and weight of blood)
- Transmural (P of blood on vessel wall)
2
Q
Arteriolar resistance is regulated by the _1_ nervous system.
A
- Autonomic
3
Q
Arteries are under _1_ pressure and Veins are under _2_ pressure.
A
- High
- Low
4
Q
Blood flows from __1 (high/low)__ pressure to __2 (high/low)__ pressure. The __3__ drives blood flow.
A
- High
- Low
- Pressure gradient
5
Q
Blood flow is inversely proportional to the _1_ of blood vessels. When blood flow increases, _1_ has decreased.
A
- Resistance (nothing is holding it back)
6
Q
What is the equation for blood flow/cardiac output/Q?
A
CO = (Mean arterial pressure [highest P] - Right arterial pressure [lowest P]) / (Total peripheral resistance [TPR])
7
Q
What are the factors that change the resistance of blood vessels (3)?
A
- Viscosity of blood (numerator)
- Length of blood vessel (numerator)
- Radius of blood vessel to the fourth power (denominator)
Resistance = (8*visc*length)/(pi*r^4)
8
Q
What is viscosity?
A
Increased viscosity is due to increased internal friction.
- thickness
- the state of being thick, sticky, and semifluid in consistency
- a measure of its resistance to gradual deformation by shear stress or tensile stress
9
Q
Increasing viscosity by increasing hematocrit will _1_ resistance and _2_ blood flow.
A
- increase
- decrease
10
Q
Increasing the length of a vessel will _1_ resistance. Increasing the radius of a vessel _2_ resistance.
A
- increase
- decrease
11
Q
If a blood vessel radius decreases by a factor of 2 then resistance _1_ by a factor of _2_ and blood flow _3_ by a factor of _4_.
A
- increases
- 16
- decreases
- 16
12
Q
_1_ resistance is illustrated by systemic circulation. Each artery in _1_ receives a fraction of the total blood flow.
A
Parallel
13
Q
When an artery is added in parallel, the total resistance _1_. In each parallel artery, the pressure is the _2_.
A
- decreases
- same
14
Q
_1_ resistance is illustrated by the arrangement of blood vessels in a given organ. _2_ are the largest contributers to this resistance.
A
- Series
- Arterioles
15
Q
As blood flows through the series of blood vessels, pressure _1_. Each blood vessel in series receives the _2_ total blood flow.
A
- decreases
- same
16
Q
_1_ flow is streamlined. _2_ flow is not and causes audible vibrations called _3_.
A
- Laminar
- Turbulent
- bruits
17
Q
A _1_ number predicts whether blood flow will be turbulent or laminar.
A
Reynold’s number
18
Q
An increased Reynold’s number increases the likelihood of _1 (laminar/turbulent)_ flow.
A
turbulent
19
Q
What are the two factors that increase a Reynold’s number?
A
- Decreased blood viscosity (ex. anemia, lower hematocrit)
- Increased blood velocity (ex. narrowing of a vessel [decreased radius)
20
Q
What is hematocrit?
A
the volume percentage of red blood cells in blood
21
Q
Pulse pressure is the difference between _1_ and _2_ presures.
A
- systolic
- diastolic
22
Q
Aging leads to a _1_ in capacitacne and an _2_ in pulse pressure.
A
- decrease
- increase
23
Q
When is systolic pressure measured?
A
**After **the heart contracts (systole) and blood is ejected in the **arterial **system.
24
Q
When in diastolic pressure measured?
A
When the heart is relaxed (diastole) and blood is returned to the heart via the veins.
25
Systolic pressure is the \_1 (highest/lowest)\_ **arterial** pressure during a cardiac cycle. Diastolic pressure is the \_2 (highest/lowest)\_ **arterial** pressure during a cardiac cycle.
1. highest
2. lowest
26
Mean arterial pressure = ?
MAP = 1/3 Systolic P + 2/3 Diastolic P
\*because most of the cardiac cycle is spent in diastole
27
Venous pressure is very \_1 (high/low)\_. Veins have a \_2 (high/low)\_ capacitance and therefore can hold \_3 (large/small)\_ volumes of blood at low pressure.
1. low
2. high
3. large
\*Capacitance is proportional to volume (numerator) and inversely proportional to pressure. As a person ages, their arteries become stiffer and less distensible/stretchy therefore capacitane of arteries decreases with age.
28
what are 4 methods of regulating arterial blood pressure?
1. Increase pumping force
2. contract veins and arterioles
3. infuse fluids
4. administer vasoconstrictors
29
which ventricle has a thicker muscular layer? why?
the left ventricle. It must pump blood through to aorta to systemic circulation.
30
how does the heart contract?
in a spiral contraction (like wringing a washcloth)
31
what is the % ejection volume referring to?
the amount of blood pushed out of the ventricles
32
capillaries have (high/low) velocity, (high/low) resistance and (high/low) cross-sectional area.
low
low
high
33
arterioles have the (highest/lowest) resistance
highest
34
the **x descent** on a jugular venous pulse reading is caused by what?
decrease in pressure in the right atrium (after peak of c wave after atrial relaxation)
35
what are the three types of action potentials? What differentiates the three?
atrial, ventricular, nodal
A/V have cardiac AP phases 0-4 while nodal only has 0, 3, amd 4
36
what does phase 4 represent in an atrial or ventricular cell?
In a nodal cell?
A/V: resting potential (constant horizontal line)
Nodal: pacemaler potential (not constant)
37
what does phase 0 represent in cardiac action potentials? what is the acting ion in a/v cells and nodal cells?
rapid depolarization and the start of an AP.
a/v: sodium Na+
nodal: Calcium Ca2+
38
phase 1 represents the brief, partial \_1\_ of ventricular and atrial action potentials. This phase is **not** present in \_2\_ APs.
1. repolarization
2. nodal
39
phase 2 looks different in every cell. It is a \_1\_ in ventricular cells, \_2\_ in atrial cells and \_3\_ in nodal cells.
1. plateau
2. abbreviated/shorter
3. missing
40
what does phase 3 represent? How is the nodal cell different?
repolarization to return to resting or pacemaker level. It is **slower **in nodal cells (remember long slope required to get to phase 0-- in a/v cells, 0 shoots straight up)
41
what channel is responsible for the phase 4 resting potential?
the inwardly rectifying K+ channel that acts as if it is voltage-gated but is not.
42
what is the function of the ikr and iks channels?
they open during phase 2 and hekp the cell to repolarize back to resting level
43
what is a refractory period?
the point where initiation of a new action potential is difficult or impossible.
44
how does the ik1 inwardly rectifying channel allows a transition to phase 0?
when the membrane is depolarized, Mg and polaymines plug up and partially block the channel therefore less K+ can pass through. This gives calcium and sodium the opportunity to depolarize the cell and maintain AP
45
what phases are included in the absolute refractory period? justify why.
Pjases 0-2. membrane depolarizes in 0 and the plateau ends by the end of 2
46
why is the supranormal refractory period associated with arrhythmias?
many of the fast sodium channels have reset and are able to produce a **reduced** amplitude AP. you don't want a contraction here becasue the atria have not been able to fill up completely.
47
a potassium channel (opens/closes) on depolarization and (opens/closes) on repolarization.
opens to let the potsassium out of the cell and make the cell more positive
closes on repolarizatoin to keep potassium in (electrical potential of K+ is approx. -90 mV)
48
what is the function of funny channels in phase 4 of the nodal action potential?
on hyperpolarization (when all of the potassium channels close) these sodium channels open and contribute to depolarizing the cell from phase 4 to 0 in the next AP round.
49
what are the two calcium channels and their roles in the nodal action potential?
CaT opens during phase 4 to help depolarize the cell
CaL (long-lasting) is responsible for the big upstroke of the nodal action potential
50
Vagal stimulation releases \_1\_ and (increases/decreases) the heart rate.
What is the effect on Na+, Ca2+ and K+ permeability?
Does this de/hyper/re-polarize the cell?
1. Ach
* decreases (parasympathetic effects)
* during pacemake potential: decreases Na+ and Ca2+ permeability and increases K+ permeability.
* Hyperpolarizes the cell
51
In nodal conductance, what is the effect of Ach on threshold?
Ach changes Na+, Ca2+ and K+ permeability and hyperpolarizes the cell. This makes the cell take longer to reach threshold and the heart rate slows
52
in nodal conductance, sympathetic stimulation releases \_1\_.
What is the effect on sodium, calcium and potassium permeabilities.
\_1\_ promotes (re/de/hyper-polarization), (inc/decreases) time btw APs and (inc/decreases) heart rate.
1. norepinephrine
* increases sodium and calcium permeability, decreases potassium permeability.
* depolarization
* decreases
* increases
53
What are the connections for lead 1 on an EKG?
(-) right arm to (+) left arm
54
What are the connections for lead 2 on an EKG?
(-) right arm to (+) left leg
| (right leg is grounded)
55
What are the connections for lead 3 on an EKG?
(-) left arm to (+) left leg
56
what does the magnitude of the mean cardiac vector depend on?
the number of individual cells that are in the provess of depolarizing or repolarizing **and ** their orientation w/ respect to each other
57
what is the mean cardiac vector for each case? (zero/non-zero)
1. all cells at rest (repolarized)
2. some cells de- and repolariz-ed/ing
3. all cells contracted depolarized)
1. zero
2. non-zero
3. zero
58
whare are the three pacemaker nodes in the heart?
SA node, AV node and the purkinje fibers.
SA node has the fastest spontaneous rate and therefore dominate. If it stops working, the other two can kick in.
59
what is the Frank-Starling mechanism?
The strength required to contract the ventricles is proportional to the pressure of the end diastolic (filling) volume
60
why does depolarization slow when going through the AV node?
allows the atria to completely empty into the ventricle
61
What are the standard EKG leads? How many of each?
3 bipolar limb leads
3 unipolar limb leads
6 unipolar precordial **chest** leads
62
why does R wave progression occur in readings of precordial chest leads?
the V1-6 is orientaed in the horizontal plane from the smaller right ventricle to the larger left ventricle.
63
What differentiates on an EKG of V5-6 precordial chest leads?
They will show a Q wave on the EKG
64
what does the PR interval indicate?
What can happen if it is prolonged?
the time it take for a signal to pass from the strium to the ventricle.
The signal can die out
65
What is Wolff-Parkinson-White Syndrome
Where the PR interval is shortened and an extra delta wave is seen on an EKG. Could lead to supraventricular tachycardia
66
what does a widened QRS indicated
slow electrical conduction through Purkinje Fibers and through the ventricular muscle.
67
the QT interval represents what? Prolonged QT syndrome increases risk for what?
duration of ventricular action potential.
If prolonged, there is an increased risk for cardiac arrhythmia
68
How are action potential and heart rate related?
a fast heart rate indicates a shorter action potental.
69
the mean QRS is normal when there is an upward deflection in which leads?
lead I and II
70
ischemic cells have a (longer/shorter) AP than normal and (de/re-polarize) faster than normal. This is due to the opening of an extra potassium channel due to metabolic distress
shorter, repolarize
71
what does subendocardial ischemia look like on an EKG?
ST segment depression
\*remember the endocardium is the first to depolarize therefore it will be that last to repolarize
72
epicardial ischemia looks like what on an EKG?
ST segment elevation
73
the left ventricle in the shape of a sphere indicate what pathogy?
heart failure
74
the epicardium gets its blood supply from where?
the endocardium
75
Calcium binds to \_1\_. \_1\_ moves tropomyosin from the \_2\_ site on the thin actin filament.
1. troponin C
2. binding
76
most of the calcium that permits actin-myosin interaction comes from the \_1\_ \_2\_ but \_3\_ calcium is required for the Calcium Indicued Calcium Release (CICR)
1. sarcoplasmic
2. reticulum
3. extracellular
77
Cardiac performance is determined by which four factors?
1. Preload
2. Afterload
3. Contractility
4. Heart Rate
78
define preload? What is its significance? How is it measure?
* the tension on the myocytes right before contraction.
* It determines the length of the sarcomeres.
* It is measured by measureing the pressure of the end diastolic volume in the ventricles
79
# define afterload.
how is it measured
should afterload increase or decrease during ejection?
* afterload is the tension in the ventricle wall during contraction
* it is proportional to left ventricle systolic pressure
* afterload should decrease during ejection since the radius of the ventricle is shrinking and blood should be flowing **out**.
80
increasing preload (increases/decreases) the velocity and extend of shorteneing if afterload is constant.
Increasing afterload has the (same/opposite) effect.
* preload increases velocity and shortening.
* afterload has the opposite effect and is negatively correlated.
81
when you have too much preload, the system backs up and can cause what?
blood can flow back into the atria and then the pulmonary veins. This will cause you to bleed out into your lungs and oxygen levels decrease.
82
what is the benefit of a stretched out sarcomere? What can cause sarcomeres to stretch?
* it increases the calciumc binding sites on the sarcoplasm therefore increasing tension and strength of the contraction.
* Increasing preload stretches sarcomeres.
83
what is contractility? how is it regulated?
the strength of a contraction
beta adrenergic stimulation
84
beta adrenergic receptors are regulated by what two things?
1. the concentration of calcium
2. the phosphorylation of proteins
85
beta adrenergic receptors have what effect on the heart (3)?
1. increase rate of contraction
2. increase peak force
3. increasing rate of relaxation
86
what binds to the beta adrenergic receptor?
norepinephrine
87
what four things can increase contractility?
1. neural input (norepinephrine)
2. increase catechols
3. digoxin
4. positive inotropic drugs (increase [Ca])
88
what can reduce contractility (5)?
1. acidosis (decrease oxygenated blood)
2. ischemia (same as above)
3. negative inotropic drug (decrease [Ca])
4. calcium channel blockers
5. beta-adrenergic blockers
89
what is the equation for cardiac output?
CO=SV \* HR
Cardiac output is equal to stroke volume multiplied b heart rate
90
how would you increase preload in a patient?
give a patient IV fluids
91
how are the semilunar and atriventricular valves opened?
high pressure in the ventricles and atria, respectively
92
what is the difference in ventricular activity for diastole and systole?
diastole is ventricular filling (relaxation), systole is ventricular emptying (contraction)
93
what is happening during the P wave?
atrial depolarization
94
What is happening during the T wave?
ventricular **repolarization** until ventricular **relaxation**
95
what is happening during the QRS complex?
ventricular **depolarizaton** to ventricular **contraction**
96
what are the 5 stages of the left ventricular pressure-volume loop?
1. isovolumetric contraction
2. ejection (period between aortic valve opening and closing)
3. isovolumetric relaxation
4. rapid ventricular filling (as soon as mitral valve opens)
5. slow ventricular filling (right before MV closes)
97
what is happening in isovolumetric contraction?
beginning of ventricular systole (contraction) but the aortic valve is closed therefore volume does not change but pressure is rising quickly.
\*valves are closed because pressure in aorta is higher than pressure in the ventricle
98
the period of rapid ejection begins when pressure within the ventricle is \_1\_ compared to the aorta or pulmonary artery?
1. greater
99
In isovolumetric relaxation, there is a \_1\_ in ventricular pressure.
It ends when there is what kind of relationship between the ventricle and atrium?
1. decrease
when the pressure in the ventricle falls below the atrium
100
What does the *a* wave represent in the atrium?
atrial contraction.
\*follows P wave of EKG
101
what does the c wave represent?
ventricular contraction
102
what does the x descent represent (3)?
1. ventricular emptying
2. thoracic volume and pressure fall
3. rapid fall in atrial pressure
103
what does the v wave represent?
flow of blood from veins to atria.
\*long period of time, AV valves are closed
104
the v wave corresponds roughly with which segment of the EKG?
ST segment
105
the *y *descent represents what?
* atria draining into the ventricles
* rapid fall in atrial pressure
106
What does the S1 heart sound represent?
the mitral and tricuspid valves closing
\*at this time the AoV and P valve are opening quietly
107
What are you hearing with the S2 heart sound?
aortic and pulmonary valve closure
\*as MV and TV valves open quietly
108
What are you hearing with the S3 heart sound?
mitral regurgitation (preload is high, pressure in ventricle increases and MV opens as a result of increased pressure)
109
what are you hearing with the S4 heart sound?
atrial contraction: the left atrium pushing against a stiff left ventricle
* high atrial pressure
* may lead to ventricular hypertrophy
110
S4 occurs during with segment of the EKG? Which part of the jugular pulse curve?
P-Q interval; a wave (aortic contraction)
111
S1 occurs during which part of the EKG diagram? jugular pulse?
* QRS complex (mainly RS when isovolumentric contraction ends)
* c wave (ventricular contraction)
112
S2 occurs during what part of the EKG?
at the end of the T wave when the ventricle has finished emptying
113
what is normal sinus rhythm?
a normal heart beat of 60-100 beats/minute
114
while standing or sitting, aspirated material is most likely to go into which bronchus? which segment?
a right lower lobe basilar segment
115
If there was a mutation in a connexin gene that interfered with gap junction assembly and inhibited efficient cell-to-cell electrical coupling in Purkinje fibers, what would you expect to see?
a widened QRS complex due to slow action potential conduction in the ventricular muscle
116
for any given afterload, increasing preload usually has the effect of (increasing/decreasing) the velocity of muscle fiber shortening
increasing
117
Which statement is true?
"the upstroke (phase 0) of the action potential directly triggers calcium release from the sarcoplasmic reticulum"
OR
"increased systolic calcium levels in the cytosol directly correlates with increased contractility"
"increased systolic calcium levels in the cytosol directly correlates with increased contractility"
118
To determine the mean QRS, what leads are evaluated in an EKG?
Lead I and aVF
119
If you had an EKG that showed a positive mean QRS axis on Lead I and a negative mean QRS axis on aVF, what is the overall mean QRS axis:
A. 0 to +90 degrees
B. +90 to 180 degrees
C. -90 to 180 degrees
D. 0 to -90 degrees
E. exactly +60 degrees
D. 0 to -90 degrees
120
If an aortic valve becomes stenotic, the peak systolic pressure would (increases/decreases) and the end systolic volume would (increase/decrease).
increase, increase
