Cardiovascular physiology Flashcards
1
Q
It describes how volume changes in response to a change in pressure.
A
Capacitance (compliance)
2
Q
The resting membrane potential (RMP) in the Ventricular Action Potential
A
−90 millivolts (mV)
3
Q
True or false
In each parallel artery, the pressure is the same.
A
True
4
Q
It is located in the interventricular septum (upper border of the muscular part of the septum), the muscular wall that separates the left and right ventricles of the heart.
A
Atrioventricular (AV) Bundle
5
Q
The Capacitance (compliance) is:
______ proportional to volume
______ proportional to pressure.
A
directly
inversely
6
Q
It is a small, specialized cluster of cells located in the wall of the RIGHT atrium, which is often referred to as the “natural pacemaker”
A
sinoatrial (SA) node
7
Q
Sympathetic or parasympathetic?
The__________ nerves slow the rhythm and diminish the rate of conduction of the impulse
the _________ nerves stimulation
A
parasympathetic
sympathetic
8
Q
[PHASES of VENTRICULAR ACTION POTENTIAL]
The cell returns to its resting membrane potential, and the ion concentrations are restored to their baseline levels. The membrane potential approaches
the K+ equilibrium potential.
A
Phase 4 (Resting Membrane Potential)
–period during which inward and outward currents (IK1) are equal
9
Q
Formula for mean arterial pressure
A
MAP = DP + 1/3(SP – DP)
or
MAP = DP + 1/3(PP)
10
Q
It is the phase of slow depolarization in the SA node action potential caused by an increase in Na + conductance, which results in an inward Na + current
called If.
It accounts for the pacemaker activity of the
SA node (automaticity).
A
Phase 4 (Pacemaker Potential - Diastolic Depolarization)
11
Q
It is a consequence of the fact that adjacent layers of blood travel at different velocities within a blood vessel.
A
Shear
12
Q
____- receptors are found on arterioles of skeletal muscle.
A
β2
13
Q
The conducting system of the heart consists of?
A
- specialized CARDIAC MUSCLE present in the sinoatrial (SA) node
- the atrioventricular (AV) node,
- the atrioventricular (AV) bundle and its right and left terminal branches,
- the subendocardial plexus of Purkinje fibers (specialized cardiac muscle fibers that form the conducting system of the heart).
14
Q
Known as the bundle of His, it is a bundle of specialized muscle fibers that serves as the only pathway of cardiac muscle, which connects the myocardium of the atria and the myocardium of the ventricles
A
Atrioventricular (AV) Bundle
15
Q
The AV node and the His–Purkinje systems are ______ pacemakers that may exhibit automaticity and override the SA node if it is suppressed.
A
latent
16
Q
True or false
the direction of blood flow is from low pressure to high pressure.
A
False
HIGH pressure to LOW pressure
17
Q
[PHASES of VENTRICULAR ACTION POTENTIAL]
It is the upstroke of the action potential due to the a rapid influx of sodium ions (Na+) through voltage-gated sodium channels, causing the cell membrane to depolarize.
A
Phase 0 (Rapid Depolarization, Peak of Action Potential)
18
Q
True or false
Each blood vessel or set of blood vessels in series receives different total blood flow.
A
False
Each blood vessel or set of blood vessels in series receives the SAME total blood flow.
19
Q
Capacitance (compliance) is __________ related to elastance, or stiffness.
A
inversely
20
Q
It is a force exerted on or against an object by something in contact with it
A
Pressure
21
Q
The veins have a ____ (low, high) capacitance and, therefore, can hold LARGE volumes of blood at low pressure.
A
high
22
Q
This action potential is responsible for triggering the contraction (systole) and relaxation (diastole) of the ventricles, the lower chambers of the heart.
A
Ventricular Action Potential
23
Q
True or false
Velocity of blood is zero at the wall and lowest at the center of the vessel.
A
False
Velocity of blood is zero at the wall and HIGHEST at the center of the vessel.
24
Q
It is a component of the conducting system that has an unstable resting potential, exhibiting phase 4 depolarization, or automaticity
A
Sinoatrial (SA) node
25
[KEY COMPONENTS OF ECG WAVEFORM)
It represents the atrial depolarization, the first upward deflection on the ECG.
P Wave
26
These are the key components of an ECG waveform
*P Wave
*PR Interval
*QRS Complex
*QT Interval
*ST segment
*T Wave
27
The ______________ is the area of a two-dimensional shape that is obtained when a three-dimensional object - such as a cylinder - is sliced perpendicular to some specified axis at a point
cross-sectional area
28
True or false
When an artery is added in parallel, the total resistance decreases.
True
29
True or false
Venous pressure is very high.
False
Venous pressure is very LOW.
30
It is located on the LOWER part of the atrial septum just ABOVE the the TRICUSPID valve, which is stimulated by the excitation wave as it passes through the atrial myocardium.
Atrioventricular (AV) Node
31
__________ predicts whether blood flow will be laminar or turbulent.
Reynolds number (Re)
32
____-receptors are found on the arterioles of the skin, splanchnic, and renal circulations.
α1
33
Issues with the SA node, such as dysfunction or irregularities in its electrical activity, can lead to heart rhythm disorders (_________)
arrhythmias
34
True or false
The SA node's specialized pacemaker activity is crucial for maintaining the rhythmic contractions of the heart and ensuring an appropriate heart rate based on the body's needs.
True
35
[PHASES of VENTRICULAR ACTION POTENTIAL]
It is the brief period of initial repolarization due to the opening of certain potassium channels, allowing the efflux of potassium ions (K+) (outward current) and decrease in Na+ conductance.
Phase 1 (Early/Initial Repolarization)
36
It's the highest arterial pressure during a cardiac cycle.
Systolic pressure
37
After the electrical impulses pass through the AV node, they travel down the _________
Atrioventricular (AV) Bundle (bundle of His)
38
[PHASES of VENTRICULAR ACTION POTENTIAL]
It is the repolarization phase, as the sustained depolarization is terminated by an increased efflux of potassium ions (Ca2+ conductance decreases, K+ conductance increases)
Phase 3 (Rapid Repolarization)
--The high K+ conductance -> large outward K+ current (IK) -> hyperpolarizes the membrane back toward the K+ equilibrium potential.
39
Velocity is ________ proportional to the
cross-sectional area at any level of the cardiovascular system.
inversely
40
________ describes the distensibility of blood vessels.
Capacitance (compliance)
41
True or false
In series resistance, blood flow through the largest artery is the same as the total blood flow through all of the capillaries.
True
42
True or false
The slight delay in the passage of the impulse from the atria to the ventricles allows time for the atria to empty their blood into the ventricles before the ventricles contract.
True
43
It is a series of pressure changes that take place within the heart, which involves complete relaxation and contraction of both the atria and ventricles
Cardiac cycle
44
the cardiac impulse is conducted to the ventricles by the ____________.
atrioventricular (AV) bundle
45
True or false
Changes in the capacitance of the veins produce changes in unstressed volume.
True
46
It conducts impulses rapidly throughout the myocardium of the heart
Conducting system
47
It is a diagnostic test that records the electrical activity of the heart over a specific period of time. This non-invasive test is commonly used to assess the heart's rhythm and electrical conduction, providing valuable information about the heart's health and function.
Electrocardiogram (ECG or EKG)
48
It is the phase of repolarization in the SA node action potential caused by an increase in K+ conductance. This increase results in an outward K+ current that causes repolarization of the membrane potential.
Phase 3
49
The most important determinant of pulse pressure is ___________.
stroke volume
50
____ node acts as a delay mechanism, briefly slowing down the impulse.
Atrioventricular (AV)
51
_________ (Increase, Decrease) in capacitance, such as those that occur with the aging process, cause increases in pulse pressure.
Decrease
52
It studies how factors affect blood flow throughout the body.
Hemodynamics
53
It refers to the sequence of electrical events that occur during the depolarization and repolarization of ventricular muscle cells (cardiomyocytes) in the heart.
Ventricular Action Potential
54
It is measured after the heart contracts (systole) and blood is ejected into the arterial system.
Systolic pressure
55
True or false
Each artery in parallel receives a fraction of the total blood flow.
True
56
It is measured when the heart is relaxed (diastole) and blood is returned to the heart via the veins.
Diastolic pressure
57
Velocity of blood flow can be expressed by the following equation:
V = Q/A
where:
* v = velocity (cm/sec)
* Q = blood flow (mL/min)
* A = cross-sectional area (cm2)
58
The rhythmic contractile process originates spontaneously in the ___________ and the impulse travels to different regions of the heart, so the atria contract first and together, to be followed later by the contractions of both ventricles together.
conducting system
59
True or false
Similar to the SA node, the AV node is influenced by the autonomic nervous system.
True
60
What component of the vasculature is this?
* progressively merge to form larger veins (e.g the vena cava)
* thin walled.
* under low pressure.
* contain the highest proportion of the blood in the cardiovascular system
* have α1-adrenergic receptors
Veins
61
True or false
The delay at the AV node serves as a safety mechanism, ensuring that the atria fully contract and empty their blood into the ventricles before the ventricles contract.
True
62
63
The Capacitance (compliance) is _______ for veins than for arteries.
greater
64
It plays a crucial role in transmitting the electrical impulses from the atrioventricular node (AV node) to the ventricles, coordinating the contraction of the heart's lower chambers.
Atrioventricular (AV) Bundle
65
The Atrioventricular (AV) bundle branches then give rise to smaller fibers known as _________.
Purkinje fibers
66
Blood flow is _______ proportional to the resistance of the blood vessels
inversely
67
It is the node that spontaneously gives origin to rhythmic electrical impulses that spread in all directions through the cardiac muscle of the atria and cause the muscle to contract.
sinoatrial (SA) node
68
True or false
A increase in venous capacitance -> decrease in unstressed volume
False
A DECREASE in venous capacitance -> decrease in unstressed volume
69
_______ flow is streamlined (in a straight line); ______ flow is not (chaotic).
Laminar; turbulent
70
True or false
As blood flows through the systemic circulation, pressure increases progressively because of the resistance to blood flow.
False
As blood flows through the systemic circulation, pressure DECREASES progressively because of the resistance to blood flow.
71
The veins contains _____ (less, more) blood volume (________ volume)
more, unstressed
72
Resistance is ______ proportional to the viscosity of the blood.
directly
73
It is an important determinant of the capacitance of the arteries
Age
74
Capacitance of the arteries ________ (increases, decreases) with age; arteries become stiffer and less distensible.
decreases
75
The normal heart contracts rhythmically at about ________ beats per minute in the resting adult.
70 to 90
76
The total resistance is the sum of the individual resistances, as expressed by the following equation:
Rtotal = Rartery + Rarterioles + Rcapillaries
77
The measured _______________ pressure is approximately equal to the left atrial pressure.
pulmonary capillary
78
Components of the vasculature
Arteries
Arterioles
Veins
Venules
Capillaries
79
The arteries contains _____ (less, more) blood volume (________ volume)
less, stressed
80
True or False
The GREATER the amount of elastic tissue there is in a blood vessel, the HIGHER the elastance is, and the LOWER the compliance is.
True
81
Capacitance (compliance) is expressed by the following equation:
C = V/P
where:
* C = capacitance or compliance (mL/mm Hg)
* V = volume (mL)
* P = pressure (mm Hg)
82
______ resistance is illustrated by the arrangement of blood vessels within a given organ.
Series
83
The average arterial pressure with respect to time.
Mean arterial pressure
84
It is for the coordinated and rhythmic contraction and relaxation of the heart chambers
Conducting system
85
Action potentials are of long duration
* in Purkinje fibers = ____ milliseconds (msec).
300
86
One of its functions is for generation of rhythmic cardiac impulses
Conducting system
87
Resistance is ______ proportional to the fourth power of the vessel radius
inversely
88
Phases ___ and ___ are not present in the SA node action potential
1 and 2
89
What component of the vasculature is this?
*the smallest branches of the arteries.
* the site of highest resistance in the cardiovascular system.
* have a smooth muscle wall that is extensively innervated by autonomic nerve fibers.
Arterioles
90
Slowest or fastest?
The intrinsic rate of phase 4 depolarization (and heart rate) is the ___________ in the SA node and the _________ in the His–Purkinje system:
SA node > AV node > His–Purkinje
fastest; slowest
91
Because diastolic pressure remains unchanged during ventricular systole, the pulse pressure _________ (increases, decreases) to the same extent as the systolic pressure.
increases
92
It is the the lowest arterial pressure during a cardiac cycle.
Diastolic pressure
93
The normal MAP range is between _________
70 and 100 mmHg
94
The speed of conduction of the cardiac impulse through the atrioventricular node (about _____ seconds) allows sufficient time for the atria to empty
their blood into the ventricles before the ventricles start to contract.
0.11
95
It is the difference between the systolic and diastolic pressures.
Pulse pressure
96
As blood flows through the series of blood vessels, the pressure ________ (decreases, increases).
decreases
97
[PHASES of VENTRICULAR ACTION POTENTIAL]
It is the plateau of the action potential marked by a sustained depolarization, mainly due to the balance between calcium influx (through L-type calcium channels) and potassium efflux. The influx of calcium prolongs the action potential and contributes to the plateau phase.
Phase 2 (Plateau phase, Membrane potential is stable)
98
________ is how your blood flows through your blood vessels.
Hemodynamics
99
blood velocity is higher in the ______ (______ cross-sectional area) than in the sum of all of the ______ (______ cross-sectional area).
aorta, small
capillaries, large
100
The pressure gradient (ΔP) drives blood flow.
True
101
True or false
Decreasing viscosity will increase resistance and decrease blood flow
False
INCREASING viscosity will increase resistance and decrease blood flow
102
True or false
The total resistance is more than the resistance of any of the individual arteries.
False
The total resistance is LESS than the resistance of any of the individual arteries.
103
What component of the vasculature is this?
*deliver oxygenated blood to the tissues.
* thick walled
* extensive elastic tissue and smooth muscle.
* under high pressure.
Arteries
104
True or false
The largest decrease in pressure occurs across the arterioles because they are the site of highest resistance.
True
105
Highest or lowest
Pressure is ______ in the aorta and large arteries and ______ in the venae cavae.
highest, lowest
106
True or false
Left atrial pressure is estimated by the pulmonary wedge pressure.
True
107
True or false
Shear is the highest at the wall and the lowest at the center of the vessel
True
108
As blood is ejected from the left ventricle into the arterial system, arterial pressure _______ (increases, decreases) because of the relatively ____ (low, high) capacitance of the arteries.
increases, low
109
They are formed from merged capillaries.
Venules
110
Features of arterial pressure
*Pulsatile (strong regular rhythm)
*Dynamic (not constant) during a cardiac cycle
111
Mean pressures in the systemic circulation
*Aorta, _____ mm Hg
*Arterioles, ____ mm Hg
*Capillaries, ____ mm Hg
*Vena cava, ____ mm Hg
*Aorta, 100 mm Hg
*Arterioles, 50 mm Hg
*Capillaries, 20 mm Hg
*Vena cava, 4 mm Hg
112
Reynolds number (and therefore turbulence) is increased by the following factors:
↓ blood viscosity (e.g., erythropenia (low RBC count)).
↑ blood velocity (e.g., narrowing of a vessel).
113
Velocity is _______ proportional to blood flow
directly
114
_______ resistance is regulated by the autonomic nervous system (ANS).
Arteriolar
115
True or false
The lower velocity of blood in the capillaries optimizes conditions for exchange of substances across the capillary wall.
True
116
Resistance is ______ proportional to the length of the vessel.
directly
117
It is calculated approximately as diastolic pressure plus one-third of pulse pressure.
Mean arterial pressure
118
Sounds heard during measurement of blood pressure, which are caused by turbulent blood flow.
The Korotkoff sounds
119
Arterial pressure is slightly _____ (lower, higher) than venous pressure.
lower
120
Normal heartbeat (HR)?
60-100 bpm
121
What component of the vasculature is this?
*largest total cross-sectional and surface area (measure of the total area that the surface of the object occupies.).
* Consists of single layer of endothelial cells thin walled
* site of exchange of nutrients, water, and gases.
Capillaries
122
Parallel resistance is illustrated by the ______ circulation
systemic
123
True or false
A catheter, inserted into the smallest branches of the pulmonary vein, makes almost direct contact with the pulmonary capillaries.
False
A catheter, inserted into the smallest branches of the pulmonary ARTERY, makes almost direct contact with the pulmonary capillaries.
