Circulation 1 Flashcards

1
Q

5 purposes of the circulatory system

A
  1. Carry nutrients, oxygen
  2. To carry waste products, CO2 to organs of excretion
  3. To move signaling molecules from one part of the body to another.
  4. To move immune cells around body
  5. Regulate body temperature
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2
Q

Diffusion over long distances

A

Slow

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3
Q

Time necessary to diffuse a molecule between two points is proportional to:

A

Square of the distance between them

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4
Q

Bulk flow is what type of transport

A

Convective flow

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5
Q

How is bulk flow controlled

A

Tubes & Pumps

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6
Q

Types of bulk flow

A
  1. Contractile chamber
  2. External pump
  3. Peristaltic contraction
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7
Q

Two types of circulatory system

A

Open & closed

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8
Q

4 components of a circulatory system

A
  1. Tubes
  2. Circulatory fluid
  3. Muscular pump
  4. Interface with the environment
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9
Q

What are the components of the vertebrate circulatory system

A
  1. Arteries
  2. Arterioles
  3. Capillaries
  4. Venules
  5. Veins
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10
Q

Which animals have single circuit circulatory systems and which have double circuit systems?

A

Single: Fishes
Double: Mammals and Birds

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11
Q

Describe the single circuit circulatory system

A
  • Heart only has one atrium and one ventricle
  • Heart goes to gill circulation (oxygenation)
  • Gill circulation goes directly to systemic circulation
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12
Q

Describe the double circuit circulatory system

A

Same as human circulatory system

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13
Q

Amphibian circulatory system

A

Same structure as human, except the pulmonary artery goes to both the lungs & the skin (called the Pulmocutaneous circuit)

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14
Q

Reptile circulatory system

A

Same as human circulatory system, except a 3rd tubule (right systemic aorta) comes out from right ventricle to pump blood to the systemic circuit

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15
Q

Law of Bulk Flow

A

Fluids flow down pressure gradient (high to low pressure). Resistance opposes this movement.

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16
Q

Law of Bulk Flow equation

A

Q=DP/R

Q=flow, DP=pressure gradient, R=resistance

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17
Q

The resistance is proportional or inversely proportional to what

A

Inversely proportional to its radius by the fourth power (1/r^4)

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18
Q

Ohm’s Law + Bulk Flow

A

Substances (electrons or fluid) move because they are acted upon by a force. Such movement is impeded by resistance

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19
Q

Why are circulatory systems named as circuits?

A

Because they are analogous to circuits and their respective series and parallel components.

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20
Q

When you add resistors in series the total resistance ___

A

Increases

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21
Q

When you add resistors in parallel the total resistance ___

A

Decreases

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22
Q

Which system would have a higher flow rate, series or parallel?

A

Parallel

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23
Q

Resistors in parallel flow rate

A

Divide up the incoming flow rate equally among the three

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24
Q

Units of flow

A

Volume/Time

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25
Q

Is flow rate larger in an artery or a capillary?

A

Artery

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26
Q

The resistance in a blood vessel is proportional or inversely proportional to what?

A

Inversely proportional to cross-sectional area of the tubule

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27
Q

The smaller the blood vessel, the greater the ___

A

Resistance

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28
Q

Because of resistance, flow rate is proportional or inversely proportional to what?

A

Directly proportional to the cross-sectional area of the vessel

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29
Q

The smaller the blood vessel, the smaller the ___

A

Flow rate

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30
Q

Velocity of flow is dependent on __ & __

A

Pressure & Cross-sectional area

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31
Q

Velocity is proportional or inversely proportional to what?

A

Inversely proportional to the cross-sectional area

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32
Q

The velocity of flow is greater in which: Artery or Capillary?

A

Capillary

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33
Q

When considering capillaries, we need to consider ___

A

The whole capillary bed (in terms of cross-sectional area)

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34
Q

The velocity of flow will be greater through which? Artery or Capillary bed?

A

Artery

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35
Q

Ranking cross-sectional area

A

(Arteries=Veins)<Capillary bed

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36
Q

Ranking velocity blood flow

A

(Arteries=Veins)>(Arterioles=Venules)>Capillary bed

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37
Q

The heart as a pump creates __

A

Pressure gradients

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38
Q

Define Diastole

A

Relaxtion. Negative Pressure. Blood flows in.

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39
Q

Define Systole

A

Contraction. Positive Pressure. Blood flows out.

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40
Q

The valve between the right atrium and ventricle is called ____

A

Right Atrioventricular Valve (Tricuspid)

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41
Q

The valve between the left atrium and ventricle is called ___

A

Left Atrioventricular Valve (Bicuspid)

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42
Q

When do the right and left atrioventricular valves open? close?

A

Open: Ventricular contraction
Close: Ventricular relaxation

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43
Q

What cells have intercalated discs?

A

Cardiac muscle cells

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44
Q

What are intercalated disks?

A

Comprised of desmosomes and gap junctions

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45
Q

What is the role of gap junctions in cardiac muscle cells?

A

To spread electrical activity from one cell to another

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46
Q

Characteristics of cardiac muscle:

A
  1. Uninucleated

2. Short and branched

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47
Q

Myogenic

A

Contraction is initiated by the cardiomyocyte

48
Q

Are vertebrate hearts myogenic?

A

Yes

49
Q

In cardiac myogenic muscle cells, how are action potentials initiated?

A

Spontaneously

50
Q

Which heart cells have the fastest rhythm (action potential frequency)?

A

Pacemaker cells

51
Q

How does the autonomic system innervate the heart rhythm?

A
  1. Sympathetic: Acceleration

2. Parasympathetic: Deceleration

52
Q

How do cardiac cells contract in synchronized rhythm?

A

Gap junctions

53
Q

What, besides the autonomic system innervates the heart rhythm?

A

Hormones

54
Q

What does the SA node stand for?

A

Sinoatrial Node

55
Q

Where is the SA node located?

A

Wall of the right atrium

56
Q

What is the role of the SA node?

A

Sets the rate and timing of cardiac muscle contractions

57
Q

Where do electrical impulses originate from in the heart?

A

SA node

58
Q

Where does the impulse transmission from the SA node go to?

A

The AV node

59
Q

What does the AV node stand for?

A

Atrioventricular node

60
Q

What is special about the AV node?

A

It has a delay of transmission of electrical impulse of 0.1 seconds.

61
Q

What does the delay of the AV node allow the heart to do?

A

Allows the atria to completely empty before the ventricles contract.

62
Q

Where does transmission go from the AV node?

A

Bundle of His –>Perkinji Fibers–>Back to apex of the heart

63
Q

What, besides the autonomic system innervates the heart rhythm?

A

Hormones

64
Q

What does the SA node stand for?

A

Sinoatrial Node

65
Q

Where is the SA node located?

A

Wall of the right atrium

66
Q

What is the role of the SA node?

A

Sets the rate and timing of cardiac muscle contractions

67
Q

Where do electrical impulses originate from in the heart?

A

SA node

68
Q

Where does the impulse transmission from the SA node go to?

A

The AV node

69
Q

What does the AV node stand for?

A

Atrioventricular node

70
Q

What is special about the AV node?

A

It has a delay of transmission of electrical impulse of 0.1 seconds.

71
Q

What does the delay of the AV node allow the heart to do?

A

Allows the atria to completely empty before the ventricles contract.

72
Q

Where does transmission go from the AV node?

A

Bundle of His –>Perkinji Fibers–>Back to apex of the heart

73
Q

Resting potential of pacemaker cells?

A

-60 mV

74
Q

Resting potential of cardiac muscle cells?

A

-85 mV

75
Q

What causes the spontaneous depolarization in pacemaker cells that passes to other cardiac cells?

A

Funny channels (I-f)

76
Q

What are funny channels (I-f)

A

Non-selective cation channels that open at hyperpolarization and close upon depolarization. Allows Na+ to leak into the cell.

77
Q

What is the cardiac cycle equivalent to?

A

A heart beat

78
Q

What is the definition of a cardiac cycle/heart beat?

A

One complete sequence of heart contraction and relaxation

79
Q

How long is a cardiac cycle?

A

0.8 sec

80
Q

What is the contraction phase called?

A

Systole

81
Q

What is the relaxation phase called?

A

Diastole

82
Q

What happens in ventricular diastole?

A

Pressure in the atria exceeds ventricular pressure. The AV valves open and the ventricles fill passively

83
Q

What happens in atrial systole?

A

Atrial contraction forces additional blood into ventricles

84
Q

What happens in ventricular systole (Isovolumentric contraction)?

A

Ventricular contraction pushes the AV valves closed and increases pressure inside the ventricle

85
Q

What is also known as ventricular systole (ventricular ejection)?

A

Increased ventricular pressure forces the semilunar valves open and blood is ejected

86
Q

What happens in ventricular diastole?

A

As the ventricles relax, pressure in the arteries exceeds ventricular pressure, closing the semilunar valves

87
Q

5 steps of the mammalian cardiac cycle

A
  1. Ventricular diastole
  2. Atrial systole
  3. Ventricular systole (isovolumetric contraction)
  4. Ventricular systole (ventricular ejection)
  5. Ventricular diastole
88
Q

What is SV?

A

Stroke Volume

89
Q

What is stroke volume?

A

The amount of blood pumped by the left & right ventricles in each contraction.

90
Q

What is the average stroke volume in humans?

A

0.07 Liters

91
Q

What is CO?

A

Cardiac output

92
Q

What is cardiac output?

A

The combined sum of output from the left & right ventricles during ventricle systole per minute

93
Q

What are the units for cardiac output?

A

Liters of blood / minutes

94
Q

What is HR?

A

Heart rate (beats/min)

95
Q

What is CO equal to?

A

CO = SV * HR

96
Q

What is the typical cardiac output?

A

~5 liters/min

97
Q

What is the typical heart rate for a human?

A

72 beats/min

98
Q

How much blood is pumped through the body in one minute?

A

ALL of it

99
Q

How much does CO2 increase during exercise?

A

4-7 fold

100
Q

What effect does the sympathetic nervous system have in the heart?

A
  1. Stimulatory

2. Causes Na+, Ca2+ cellular influx–>Increased depolarizations–>Increased heart rate

101
Q

What effect does the parasympathetic nervous system have in the heart?

A
  1. Inhibitory

2. Causes increased K+ cellular efflux & decreased Ca2+ influx–>Decreased depolarizations–>Decrease heart rate

102
Q

Where is the cardiovascular control center?

A

Medulla Oblongota

103
Q

Molecular pathway of parasympathetic action on the heart:

A
  1. Medulla stimulates parasympathetic neurons innervating heart
  2. Neurons release Acetylcholine
  3. Acetylcholine binds to muscarinic receptors of autorhythmic cells
  4. Binding causes an increase in K+ efflux & decrease in Ca2+ influx
  5. Hyperpolarizes cell
  6. Increases time for one depolarization
  7. Decreases heart rate
104
Q

Molecular pathway of sympathetic action on the heart:

A
  1. Medulla stimulates sympathetic neurons
  2. Neurons stimlute adrenal medulla (from adrenal glands)
  3. Adrenal medulla releases epinephrine and norepinephrine
  4. Epinephrine and norepinephrine bind to Beta-1 receptors of autorhythmic cells
  5. Binding causes increase in Na+ & Ca2+ influx
  6. Increases rate of depolarizations
  7. Increases heart rate
105
Q

Molecular pathway of parasympathetic action on the heart:

A
  1. Medulla stimulates parasympathetic neurons innervating heart
  2. Neurons release Acetylcholine
  3. Acetylcholine binds to muscarinic receptors of autorhythmic cells
  4. Causes an increase in K+ efflux & decrease in Ca2+ influx
  5. Hyperpolarizes cell
  6. Increases time for one depolarization
  7. Decreases heart rate
106
Q

Molecular pathway of sympathetic action on the heart:

A
  1. Medulla stimulates sympathetic neurons
  2. Neurons stimlute adrenal medulla (from adrenal glands)
  3. Adrenal medulla releases epinephrine and norepinephrine
  4. Epinephrine and norepinephrine bind to Beta-1 receptors of autorhythmic cells
  5. Binding causes increase in Na+ & Ca2+ influx
  6. Increases rate of depolarizations
  7. Increases heart rate
107
Q

Explain in depth the Beta-1 mechanism at which sympathetic innervation of the heart occurs.

A
  1. Epinephrine or norepinephrine bind to Beta-1 receptor
  2. G-s of GPCR complex binds to Adenlyl cyclase
  3. Adenlyl cyclase converts ATP to cAMP
  4. cAMP activates protein kinases
  5. Protein kinases stimulate opening of funny Na+ channels (influx) & T-Type Ca2+ channel (influx).
108
Q

How do we measure the cardiac cycle?

A

EKG/ECG

109
Q

Components of the EKG

A

P wave, QRS complex, T wave

110
Q

What is happening during the P wave of an EKG?

A

Activation of the atria

111
Q

What is happening during the QRS complex of the EKG?

A

Activation of the ventricles

112
Q

What is happening during the T-wave of an EKG?

A

Recovery wave of ventricles (and atria?)

113
Q

What type of fibrillation is fatal?

A

Ventricular fibrillation

114
Q

What stimulates the P-wave?

A

SA node

115
Q

What causes the delay between the P-wave and the QRS complex?

A

AV node

116
Q

What causes the Q part of the QRS complex

A

Bundle of His

117
Q

What causes the R&S part of the QRS complex

A

Perkinji Fibers