Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physiology > Cardiovascular > Flashcards

Cardiovascular Flashcards

1
Q

The pulmonary circuit goes from the ______________ ventricle to the _____________ atrium.

A

Right

Left

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The systemic circuit can be described as going from the ___________ ventricle to the __________
atrium

A

Left

Right

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

2 functions of the fibrous connective tissue valves between the chambers and major arteries

A
  1. Preventing backward flow

2. Acts as electrical insulator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the significance of the heart valves blocking most of the electrical signals between the atria and ventricles

A

This ensures the electrical signals can be directed through a specialized conduction system to the apex of heart for bottom to top contraction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The special connections between cardiomyocytes are called

A

Intercalated disks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What 2 functional features does the intercalated disks contain

A
  1. Gap Junctions

2. Desmosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are 2 functions provided by gap junctions and desmosomes

A
  1. Gap junctions allow electrical signals to pass rapidly from cell to cell
  2. Desmosomes transfer force from cell to cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How are 1% of myocardiocytes specialized

A

They generate action potential spontaneously

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Define myogenic

A

This means it or originates within the heart muscle itself. This allows the heart to contract without connections to other parts of the body.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where does the action potential originate in the heart

A

Pacemakers cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How does the action potential spread into the contractile cells

A

Gap junctions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The rapidly rising phase of the contractile cell action potential is based on what 2 ions

A

Ca++

Na+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

L type calcium channels on the membrane of the cardiac contractile cells are what type

A

Voltage gated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The influx of calcium releases the calcium from the SR by activating what channels

A

Ryanodine receptor calcium release channels (RyR)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What percentage of calcium is released from the SR that is needed for muscle contraction

A

90%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

The strength of cardiac contraction depends on what 2 things

A
  1. Sarcomere length at the beginning of contraction

2. The amount if calcium released into the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How do calcium and the amount of active crossbridges play a role in the force a muscle generates

A

The force generated by cardiac muscle is proportional to the number of cross bridges that are active. The more calcium that goes into the cell, the more calcium that is released from the SR, and the more calcium that binds to troponin, enhancing the ability of myosin to form crossbridges with actin and creating additional force.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

In cardiac muscle, what happens when cytoplasmic calcium concentrations decrease

A

Calcium unbinds from troponin which leads to myosin to release actin, this causes contractile filaments to slide back and muscles to relax

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are 2 ways that calcium is removed from the cytoplasm of cardiac muscle cells

A
  1. Calcium is transported back into SR with help of calcium ATPase
  2. Calcium is removed from cell via Na+ -Ca++ exchange (NCX)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How does the NCX antiport work

A

1 Ca++ moves out of the cell for every 3 Na++ moving into the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

The number of active cross bridges is determined by what

A

How much calcium is bound to troponin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What role does the length tension relationship play in the contractile strength of cardiac muscle

A
  • Longer sarcomere length can lead to stronger contraction
  • Greater sarcomere length means larger internal volume
  • Greater volume needs a stronger contraction to push it out
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

The Frank Starlin’s law of the heart states that

A

When cardiac muscle is stretched more, It contracts more forcefully

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

In the contractile myocardiocytes the resting membrane potential is about

A

-90mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

During the contractile cells action potential, the plateau phase is caused by what 2 ions

A

K+ and Ca++ ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What ion is effluxing and influxing during the plateau phase of the contractile cells AP

A

K++ effluxing, Ca++ influxing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What causes the repolarization phase of the contractile cells

A

Potassium ion efflux

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

For the autorhythmic cells, the membrane potential is not stable, but fluctuates from what to what

A

-60mV to -40mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the threshold for If channels

A

-40mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

When the If channel opens what comes out of the cell and what goes into the cell

A

Na+ influx

K+ efflux

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is another name for the unstable membrane potential or type of graded potential of the myocardio autorrhythmic cells

A

Pacemaker potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What causes the are autorrhythmic cells rapid rising phase of depolarization

A

Ca++ion influx

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What causes the autorhythmic cells repolarization phase

A

Ca channels close, slow K channels open, resulting in the efflux of K+ ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What to type of myocardial muscle does the heart have

A

Autorhythmic cells and myocardial contractile cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

The autorhythmic cells are also called

A

pacemakers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

The term intrinsic myogenic indicates that the heart muscle is the source of

A

The electrical signal that stimulates heart contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

The Na+ influx during the action potential in a cardiac contractile cell causes

A

The opening of L type calcium channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is a key property of cardiac muscle cells

A

The ability of a single muscle fiber to execute graded contractions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What does it mean to execute a graded contraction

A

The fiber varies the amount of force it generates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

The flattening of the action potentials of myocardial contractile cells, called the plateau phase, is due to a combination of

A

K+ efflux and Ca++ influx at the same time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

The end of the plateau phase of cardiac contractile cell action potentials is due to the

A

Closing of Ca++ channels and opening of K+ channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q
  1. A typical action potential of a myocardial contractile cell lasts?
  2. What does this prevent ?
A
  1. At least 200 msec

2. Wave summation and tetany

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Autorhythmic cells can generate action potentials spontaneously because they have

A

An unstable membrane potentials at -60mV which slowly drifts up towards threshold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Autorhythmic cells are also called

A

Pacemakers because they set the rate of the heartbeat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

List the order of events of electrical conduction in the heart

A

SA node–>Internodal pathways–>AV node–>AV bundle if His–>Bundle branches–> Purkinje fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

How does electrical conduction in the myocardial cells transfer or spread

A

Autorhythmic cells spontaneously fire action potentials. Depolarizations of the autorhythmic cells then spread rapidly to adjacent contractile cells through gap junctions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What is the pacemaker of the heart

A

Sinoatrial node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What is pacemaker potential

A

When the potential for autorhythmic cells drifts up slowly to threshhold, causing an action potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What is the threshold for autorhythmic cell

A

-40mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Once autorhythmic cells reaches its threshold, which channels open and which channels close, and what ion influx occurs

A

Voltage gated calcium channels open, I f channels close, Ca++ influx occurs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Diastole is

A

The time during which cardiac muscle relaxes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Systole is

A

The time during which the cardiac muscle contracts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

When both atria and ventricles are relaxing, which valves are open

A

AV valves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Is the heart in atrial and ventricular systole at the same time

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

When both aria and ventricles are relaxing, where is blood flowing

A

Into the ventricles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

What percentage of ventricular filling depends on atrial contraction

A

20%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

What wave or wave segment on the ECG is associated with ventricular filling

A

P wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

What electrical event precedes ventricular systole

A

Ventricular Depolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

As the ventricles contract, why do the AV valves close

A

Because ventricular pressure is higher than atrial pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

What creates the heart sounds

A

Vibrations following AV closure and semilunar closure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Explain what is happening during isovolumetric ventricular contraction

A

Force without movement or change in volume. The 1st phase of ventricular contraction pushes AV valves closed but does not create enough pressure to open semilunar valves. The volume in the ventricles has not changed. It maintains the end diastolic volume or maximal volume from the end of atrial systole.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What happens to pressure in the ventricles during isovolumetric then ventricular contraction

A

It is increasing rapidly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What causes the semilunar valves to open, allowing blood to be ejected into the arteries

A

As then ventricles contract, enough pressure is generated to open the semilunar valves and push blood into the arteries. This is the driving force for blood flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

How is ventricular pressure in comparison to arterial pressure when blood flows out of the ventricles

A

Then vetricular pressure is higher than arterial pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

What happens to ventricular pressure as the ventricles relax

A

Then ventricular pressure decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

What causes the semi lunar about to close

A

Once then ventricular pressure falls below the pressure in the arteries, blood starts to flow backward in the heart. This back flow of blood fills the cup-like cusps of semilunar valves, forcing them together into the closed position

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

When do AV valves open

A

When ventricular relaxation causes ventricular pressure to become less than arterial pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

What is stroke volume

A

That amount of blood pumped by one ventricle during a contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

What is the calculation equation for stroke volume

A

Volume of blood before contraction - volume of blood after contraction
EDV-ESV=SV (mL [per beat])

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

If the EDV increases and the ESV decreases, has the heart pumped more or less blood

A

More

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

What is the calculation equation for cardiac output

A

CO (mL / min) =HR × SV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

What is an average value for (70kg male) stroke volume

A

70 mL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

What is an average (70kg male) for cardiac output

A

5040 ml/min or 5 L/min

74
Q

During the isovolumetric phase of ventricular systole which valves are closed

A

The atrioventricular valves and semilunar valves are closed

75
Q

What is end systolic volume

A

The amount of blood in the ventricle available to be pumped out of the heart during the next contraction

76
Q

The term that describes the volume of blood circulated by the heart in one minute

A

Cardiac output

77
Q

Explain the antagonistic control of heart rate by the sympathetic neurons

A

NE–>B1 receptor of autorhythmic cells–> Increased Na and Ca influx–> Increased rate of depolarization–> Increased heart rate

78
Q

Explain antagonistic control of heart rate by parasympathetic neurons

A

ACh–> muscarinic receptors of autorrhythmic cells–> Increased K efflux, Decreased Ca influx–> Hyperpolarization of cell–> Decreased rate of depolarization–> Decreased heart rate

79
Q

How does acetylcholine affect membrane potential of the pacemaker cell

A

It causes the cell to take longer to reach threshold, delaying the onset of the action potential in the pacemaker and slowing the heart rate

80
Q

Epinephrine and norepinephrine increase ion flow through what channel(s)

A

I f and Ca++ channels

81
Q

Stimulation of the beta receptors on heart muscle results in what type of signaling

A

cAMP signaling

82
Q

How does NE and epi effect Pacemaker cells

A

When cAMP binds to open I f channels, they remain open longer more rapid Cation (Ca++, Na+) entry speeds up the rate of the pacemaker depolarization causing the cell to reach threshold faster and increasing the rate of action potential firing, resulting in increased heart rate

83
Q

Stretching a myocardial cell allows more __________________ and increases ________________

A

Ca++ to enter, the force of a contraction

84
Q

What factors affect cardiac output

A

Stroke volume, Heart rate, Contractile force

85
Q

What factors affect force generated

A

Length of muscle fibers at the beginning of the contraction, number of calcium ions available ( Contractility)

86
Q

How does the cardiovascular system create a region of higher pressure

A

The heart creates high pressure when it contracts

87
Q

As blood moves away from the heart what happens to the pressure and why

A

Pressure falls continuously as blood moves farther from the heart. As blood moves through the closed loop of blood vessels, pressure is lost because of friction between fluid and blood vessel walls.

88
Q

Does venous return increase ESV or EDV

A

End diastolic volume

89
Q

How does sympathetic output increase the force of cardiac muscle contractions

A

An increase in sympathetic output constricts veins, Decreasing holding capacity and increasing venous return. This increases the stretch of the heart which increases cross bridges and calcium into the heart. This results in an increased contractility of the heart and redistribution of blood to arterial side,increasing MAP.

90
Q

When voltage gated calcium channels are phosphorylated, Their probability of opening is ______________ and more __________________ enters the cell

A

Increased, calcium

91
Q

A blood flowed through the a order is 5 L/min then what’s the blood flow through the pulmonary artery

A

5 L/min

92
Q

Liquids and gasses flow from areas of ___________

pressure to areas of __________ pressure

A

High, low

93
Q

Where is the highest pressure and lowest pressures in the blood vessel is found

A

Aorta, venae cavae

94
Q

What happens to pressure when the heart relaxes or the blood vessels dilate

A

Pressure decreases (as container expands)

95
Q

What is a pressure gradient in the cardiovascular system

A

Change in pressure from regions of higher pressure to regions of lower pressure

96
Q

If fluid is flowing through 2 identical tubes and tube A has a pressure gradient of 50 and tube B has a pressure gradient of 65 which tube will have the greatest flow

A

Tube B, the one with the greatest pressure gradient

97
Q

What is resistance

A

The tendency of the cardiovascular system to oppose blood flow

98
Q

What happens to flow as resistance increases

A

Flow decreases

99
Q

What is the mathematical equation of flows relationship with resistance

A

Flow 🔀 1/R

100
Q

3 parameters that influence resistance for fluid flowing through a tube

A
  1. The radius of a tube
  2. The length of the tube
  3. The viscosity of the fluid
101
Q

What factors increase resistance of fluid in a tube

A

Increased length and increased viscosity

102
Q

What decreases resistance through a tube

A

An increased radius of a tube

103
Q

In humans which of the 3 factors that influence resistance are not constant and play the most significant role in determining resistance to blood flow

A

Radius of Tube

104
Q

When the radius of a tube decreases what happens to the resistance of the tube

A

It increases

105
Q

What happens to flow through a tube where the radius decreases and the resistance increases

A

Flow decreases

106
Q

Is the radius of a to doubles what happens to the resistance

A

It decreases and flow increases

107
Q

Define diameter of the vessel and explain the effects on resistance to blood flow

A

Diameter is the length through the center of a circular object. If there is vasoconstriction or narrowing of the diameter then resistance will increase and flow will decrease. If there is vasodilation or an increase in the diameter then resistance will decrease and flow will increase.

108
Q

Equation that expresses the relationship between flow, the pressure gradient and resistance

A

Flow🔀 🔺️P/R

109
Q

What is the name of the receptors that detect blood pressure changes

A

Baroreceptors

110
Q

Where are the baroreceptors for blood pressure located and what is the significance about these locations

A

They’re located in the walls of carotid arteries and aorta. The blood flow to brain and body is monitored here.

111
Q

If you are monitoring the electric activity of the sensory neurons linking baroreceptors to the cardiovascular control center, Would you observe any electrical activity when a person’s blood pressure is in normal range? Are these receptors tonic are phasic

A

These receptors are tonically active and fire action potentials continuously at normal blood pressures. The frequency of action potential changes in response to blood pressure by increasing or decreasing.

112
Q

Describe the Baroreceptor reflex when responding to an increased blood pressure

A

A increase blood pressure–> Responds by increasing frequency firing rate of baroreceptor–> Sensory neurons send information to–> Cardiovascular control center–> Response is decrease sympathetic output and Increased para sympathetic output–> Less NE and more ACh–> vasodilation, Decreased contractility, heart rate ,blood pressure,

113
Q

A decrease in blood pressure results in what type of sympathetic activity and what type of parasympathetic activity

A

Increase sympathetic and decreased parasympathetic activity

114
Q

What effect will and increase in sympathetic activity have on heart rate force of contraction and arteriolar diameter

A

Increase heart, Increase contractility, Decreased arteriolar diameter (vasoconstriction)

115
Q

Pericytes

A

Contractile cells around capillary endothelium and interstitial fluid. The tightness of capillary permeability means less leaky capillaries This is seen in blood-retina-barrier and BBB. That also help influence capillary growth.

116
Q

Arteries major function and physical characteristics

A

They are the driving pressure for blood flow during ventricular relaxation known as or “pressure reservoir.” Made up of endothelium, thick smooth muscle, Large elastic fibrous tissue. Low volume: 11%

117
Q

Major function of arterioles and physical characteristics

A

Direct distribution of blood flow to individual tissues by selectively constricting or dilating. Known as “variable resistance.” Endothelium, Smooth muscle. It is Divergent has several layers that contract and relax due to chemical changes

118
Q

Major function of the venules and physical characteristics

A

Flows from capillaries to venules. Endothelium, Fibrous tissue, Larger ones have smooth muscle

119
Q

Veins major functions and physical characteristics

A

Volume reservoir where blood can be sent to arterial side of circulation if blood pressure falls too low. They have one way valves. Can hold as much as 60% of the body’s volume. Made up of endothelium elastic and fibrous tissue and smooth muscle. Also less elastic and expand easier.

120
Q

Capillary major function and characteristics

A

Leaky epithelium allows exchange of materials between plasma ISF and cell body. Made up of endothelium only

121
Q

What is the difference between flow and the velocity of flow

A

Flow is measured in liters per minute and is the volume of blood that passes a given point in system per unit time.–> How much
Velocity is measured in centimeters per minute and is the distance a fixed volume of blood travels in a given period of time.–> How fast

122
Q

What is MAP

A

Mean arterial pressure. The primary driving force for blood flow maintained by arteries during heart relaxation phase

123
Q

Equation that expresses MAP, cardiac output, peripheral resistance in relation to each other

A

MAP🔀CO X Peripheral resistance

124
Q

What kinds of problems that result when blood pressure’s too low or too high

A
  1. If it is too low then the driving force will be unable to oppose gravity and blood flow and oxygen to brain will be impaired resulting in dizziness and fainting.
  2. If the blood pressure is too high then pressure on blood vessel walls will weaken areas which could lead to rupture and bleeding into tissues. This can potentially cause a CVA, Aortic distension or dissection, hemorrhage and/or death.
125
Q

How do changes in blood volume affect blood pressure

A

If blood volume decreases then blood pressure will decrease.

If blood volume increases then blood pressure will increase

126
Q

Explain myogenic auto regulation

A

Vascular smooth muscle has the ability to regulate its own state of contraction.

If smooth muscle stretches then mechanically gated channel open allowing Cations to depolarize the cell and open voltage gated calcium channels. Calcium flows into the cell, down its electrochemical gradient. Calcium entering the cell combines with calmodulin and activates MLCK. This increases myosin ATPase activity and crossbridge activity resulting in contraction/constriction.

127
Q

Explain active hyperemia

A

This is a process in which an increase in blood flow follows an increase in metabolic activity.
If aerobic metabolism increases, then tissue oxygen will decrease and carbon dioxide will increase. This will stimulate vasodilation which is a decrease in resistance and increase of blood flow to tissues. This will meet metabolic demand and remove CO2 and bring more O2 to tissues when more blood comes to area.

128
Q

What type of exchange between the plasma and that interstitial fluid could take place at the capillary

A

The exchange of gasses such as 02 & CO2, nutrients, fluid, dissolved solutes, proteins, macromolecules; trancytosis

129
Q

For substances that diffuse freely across capillary walls, what factors are the most important for determining the rate of diffusion

A
  1. The concentration gradient between plasma and the interstitial fluid.
  2. For O2 and CO2, Plasma concentrations reach equilibrium with ISF and cells by the time blood reaches the venous end of the capillary.
130
Q

Distinguish between filtration and absorption in capillaries

A

Absorption is bulk flow into capillaries

Filtration is bulk flow out of capillaries

131
Q

What 3 forces determine the direction of capillary bulk flow

A
  1. Hydrostatic pressure (Pcap)
  2. colloid osmotic pressure (Posm)
  3. Interstitial fluid pressure (Pif)
132
Q

What is hyperemia

A

Increased blood flow. Vasodilation leads to hyperemia.

133
Q

What is the role of endothelium in a blood vessel

A

It is the inner lining of a blood vessel. Its functions are secreting Paracrine, helps regulate BP, blood vessel growth, absorption.

134
Q

What creates the osmotic pressure gradient between the plasma and the interstitial fluid

A

The concentration difference of proteins between plasma and ISF creates osmotic pressure. They are mainly present in the plasma and mostly absent from the ISF.

135
Q

Compare net fluid flow at the arterial end of capillary with net fluid flow at the venous end

A

The fastest flow is in the relatively small diameter arterial system. The slowest flow is in the capillaries which have the largest cross section. This allows enough time for diffusion to go to equilibrium

136
Q

What are their to typical causes of edema

A
  1. Inadequate drainage of lymph

2. Blood capillary filtration that greatly exceeds capillary absorption

137
Q

What are capillaries

A

Microscopic vessels in which blood exchanges materials with the interstitial fluid

138
Q

Do arteries transport blood towards the heart or away from the heart

A

Transport blood away from the heart

139
Q

What type of gradient is the driving force for blood flow

A

Pressure

140
Q

What effect would blocked calcium channels have on the rhythm of the heart

A

A slower rate due to decreased rate of depolarization

141
Q

What would be the effect on the rhythm of the heart is the ICF became high in potassium (hyperkalemia).

A

A decreased rhythm due to it taking longer to reach a potential or get to threshold

142
Q

What would be the effect on the heart rhythm if the intracellular concentration of potassium was lowered

A

A slower rhythm due to it taking longer to repolorize

143
Q

What effect would and increase perm ability to sodium have on the rate of the pacemaker potentia

A

A steeper depolarization, reaching threshold quicker, more AP, increased heart rate

144
Q

What effect would and increase permeability to calcium have on the effect of the rate of the pacemaker potential

A

It would have a sympathetic effect, Increasing calcium permeability would cause a steeper depolarization and speed up the rate of depolarization

145
Q

What would be the effect of sympathetic stimulation on the rate of pacemaker potential

A

NE/Epi bind to B1 adrenergic receptors, cAMP alters If channels and acts as 2nd messenger and activates Ca2+ channels, increasing permeability to Ca2+

146
Q

What effect is parasympathetic output have on the heart rate

A

Acetylcholine activates muscarinic receptors that activate K+ channels
K+ Permability increases, more K+ efflux, hyperpolarizing cell
Ca2+ permeability decreases–>slower rate of depolarization
AP shallow and takes longer to get to threshold
END RESULT–>Slower heart rate

147
Q

What is CICR

A

Calcium induced, calcium release.
It is the process of EC coupling in cardiac muscle when calcium entry opens Ryanodine receptor calcium release channels and the SR

148
Q

Is filtration in capillaries exactly = to absorption

A

No. Filtration is usually greater than absorption resulting and bulk flow of fluid out of capillary and into interstitial space. If it were equal there would be no net movement of fluid.

149
Q

What is one function of the lymphatic system as a relates to the concept of capillary exchange

A

Restoring fluid lost from capillaries to the circulatory system and proteins (filtered out)

150
Q

What change and a blood vessel radius would increase resistance

A

Decreased blood vessel radius

151
Q

When a quantitee is expressed as 4 cm a minute then it is describing what

A

The velocity of flow

152
Q

Smooth muscle is absent in the walls of what type of vessel

A

Capillaries

153
Q

In active hyperemia blood flow to a tissue will increase if the

A

level of carbon dioxide at the tissues increase

154
Q

What dehydration cause a decrease in blood pressure

A

Yes

155
Q

What does myogenic auto regulation mean

A

Stretched smoothed muscle in a blood vessel constricts reflexively

156
Q

In order to cause vasodilation of most vascular smooth muscle, what type of stimulation output is needed

A

Decreased sympathetic stimulation

157
Q

Compared to arteries the velocity of flow of the blood through the capillaries is

A

Much slower

158
Q

Due to the difference in opposing forces, there is net ______________ occurring at the arterial end of most capillaries, coupled with net ______________ at the venous end

A

Filtration, absorption

159
Q

What is reactive hyperemia

A

If blood flow to a tissue is occluded and 02 levels fall and metabolic paracrine signals such CO2 and H+ accumulates in ISF, then endothelial cells synthesize NO–>vasodilation. Blood flow to area washes away vasodilator, radius of vessel returns to normal

160
Q

Osmotic pressure resulting from presence of plasma proteins in blood are called

A

Oncotic and colloid osmotic pressure

161
Q

If a person is in bed for several days the baroreceptor reflex may fail upon standing. Why?

A
  1. Blood pools in the feet and legs
  2. There is a decreased blood flow to the brain upon standing.
  3. The kidneys have decrease the blood volume
  4. Blood pools in the feet and legs and there is decreased blood flow to the brain
162
Q

The inner lining of a blood vessel is called

A

Endothelium

163
Q

The mean arterial pressure is important because

A

It represents a driving pressure for blood flow

164
Q

Increased blood volume does what to blood pressure

A

Increases blood pressure

165
Q

Restoring lost fluid from the capillaries back to the circulatory system is one of the major functions of what system

A

Lymphatic

166
Q

One purpose of valves in the cardiovascular system is to

A

Ensure that blood close in one direction

167
Q

Add and intercalated disc, two cardiac muscle cells are connected by what

A

Gap junctions

168
Q

The term intrinsic myogenic indicates that the heart muscle is the source of

A

The electrical signal that stimulates heart contraction

169
Q

The sodium influx during the action potential in a cardiac contractile cell causes

A

Opening of L type calcium channels

170
Q

Stretching a myocardial cell

A

Allows more calcium to enter and increases the force of contraction

171
Q

The flattening of the action potentials of myocardial contractile cells called the plateau phase is due to a combination of ________ efflux and ________influx occurring at the same time

A

K+, Ca2+

172
Q

The end of the plateau phase of cardiac contractile cell action potentials is due to the __________ of Ca2+ channels and ___________ of K+ channels

A

Closing, opening

173
Q

A typical action potential of a myocardial contractile cell last how many seconds? What does this prevent?

A

At least 200 milliseconds. This prevents wave summation and tetany

174
Q

Auto rhythmic cells can generate action potentials spontaneously because they have

A

Unstable membrane potentials, -60 mV

175
Q

Autorhythmic cells are also called

A

Pacemakers because they set the rate of the heart beat

176
Q

During the isovolumic phase of ventricular systole, the atrioventricular valves and semi lunar valves are

A

Closed

177
Q

The term used to describe the amount of blood in the ventricle available to be pumped out of the heart during the next contraction is

A

End systolic volume

178
Q

The term that describes a volume of blood circulated by the heart in one minute is

A

Cardiac output

179
Q

Epinephrine and norepinephrine increase ion flow through what channels

A

If and Ca2+ channels

180
Q

Stimulation of the beta receptors on heart muscles result in

A

cAMP SIGNALING

Physiology (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions