Circulation 1 Flashcards
1
Q
5 purposes of the circulatory system
A
- Carry nutrients, oxygen
- To carry waste products, CO2 to organs of excretion
- To move signaling molecules from one part of the body to another.
- To move immune cells around body
- Regulate body temperature
2
Q
Diffusion over long distances
A
Slow
3
Q
Time necessary to diffuse a molecule between two points is proportional to:
A
Square of the distance between them
4
Q
Bulk flow is what type of transport
A
Convective flow
5
Q
How is bulk flow controlled
A
Tubes & Pumps
6
Q
Types of bulk flow
A
- Contractile chamber
- External pump
- Peristaltic contraction
7
Q
Two types of circulatory system
A
Open & closed
8
Q
4 components of a circulatory system
A
- Tubes
- Circulatory fluid
- Muscular pump
- Interface with the environment
9
Q
What are the components of the vertebrate circulatory system
A
- Arteries
- Arterioles
- Capillaries
- Venules
- Veins
10
Q
Which animals have single circuit circulatory systems and which have double circuit systems?
A
Single: Fishes
Double: Mammals and Birds
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
12
Q
Describe the double circuit circulatory system
A
Same as human circulatory system
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)
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
15
Q
Law of Bulk Flow
A
Fluids flow down pressure gradient (high to low pressure). Resistance opposes this movement.
16
Q
Law of Bulk Flow equation
A
Q=DP/R
Q=flow, DP=pressure gradient, R=resistance
17
Q
The resistance is proportional or inversely proportional to what
A
Inversely proportional to its radius by the fourth power (1/r^4)
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
19
Q
Why are circulatory systems named as circuits?
A
Because they are analogous to circuits and their respective series and parallel components.
20
Q
When you add resistors in series the total resistance ___
A
Increases
21
Q
When you add resistors in parallel the total resistance ___
A
Decreases
22
Q
Which system would have a higher flow rate, series or parallel?
A
Parallel
23
Q
Resistors in parallel flow rate
A
Divide up the incoming flow rate equally among the three
24
Q
Units of flow
A
Volume/Time
25
Is flow rate larger in an artery or a capillary?
Artery
26
The resistance in a blood vessel is proportional or inversely proportional to what?
Inversely proportional to cross-sectional area of the tubule
27
The smaller the blood vessel, the greater the ___
Resistance
28
Because of resistance, flow rate is proportional or inversely proportional to what?
Directly proportional to the cross-sectional area of the vessel
29
The smaller the blood vessel, the smaller the ___
Flow rate
30
Velocity of flow is dependent on __ & __
Pressure & Cross-sectional area
31
Velocity is proportional or inversely proportional to what?
Inversely proportional to the cross-sectional area
32
The velocity of flow is greater in which: Artery or Capillary?
Capillary
33
When considering capillaries, we need to consider ___
The whole capillary bed (in terms of cross-sectional area)
34
The velocity of flow will be greater through which? Artery or Capillary bed?
Artery
35
Ranking cross-sectional area
(Arteries=Veins)
36
Ranking velocity blood flow
(Arteries=Veins)>(Arterioles=Venules)>Capillary bed
37
The heart as a pump creates __
Pressure gradients
38
Define Diastole
Relaxtion. Negative Pressure. Blood flows in.
39
Define Systole
Contraction. Positive Pressure. Blood flows out.
40
The valve between the right atrium and ventricle is called ____
Right Atrioventricular Valve (Tricuspid)
41
The valve between the left atrium and ventricle is called ___
Left Atrioventricular Valve (Bicuspid)
42
When do the right and left atrioventricular valves open? close?
Open: Ventricular contraction
Close: Ventricular relaxation
43
What cells have intercalated discs?
Cardiac muscle cells
44
What are intercalated disks?
Comprised of desmosomes and gap junctions
45
What is the role of gap junctions in cardiac muscle cells?
To spread electrical activity from one cell to another
46
Characteristics of cardiac muscle:
1. Uninucleated
| 2. Short and branched
47
Myogenic
Contraction is initiated by the cardiomyocyte
48
Are vertebrate hearts myogenic?
Yes
49
In cardiac myogenic muscle cells, how are action potentials initiated?
Spontaneously
50
Which heart cells have the fastest rhythm (action potential frequency)?
Pacemaker cells
51
How does the autonomic system innervate the heart rhythm?
1. Sympathetic: Acceleration
| 2. Parasympathetic: Deceleration
52
How do cardiac cells contract in synchronized rhythm?
Gap junctions
53
What, besides the autonomic system innervates the heart rhythm?
Hormones
54
What does the SA node stand for?
Sinoatrial Node
55
Where is the SA node located?
Wall of the right atrium
56
What is the role of the SA node?
Sets the rate and timing of cardiac muscle contractions
57
Where do electrical impulses originate from in the heart?
SA node
58
Where does the impulse transmission from the SA node go to?
The AV node
59
What does the AV node stand for?
Atrioventricular node
60
What is special about the AV node?
It has a delay of transmission of electrical impulse of 0.1 seconds.
61
What does the delay of the AV node allow the heart to do?
Allows the atria to completely empty before the ventricles contract.
62
Where does transmission go from the AV node?
Bundle of His -->Perkinji Fibers-->Back to apex of the heart
63
What, besides the autonomic system innervates the heart rhythm?
Hormones
64
What does the SA node stand for?
Sinoatrial Node
65
Where is the SA node located?
Wall of the right atrium
66
What is the role of the SA node?
Sets the rate and timing of cardiac muscle contractions
67
Where do electrical impulses originate from in the heart?
SA node
68
Where does the impulse transmission from the SA node go to?
The AV node
69
What does the AV node stand for?
Atrioventricular node
70
What is special about the AV node?
It has a delay of transmission of electrical impulse of 0.1 seconds.
71
What does the delay of the AV node allow the heart to do?
Allows the atria to completely empty before the ventricles contract.
72
Where does transmission go from the AV node?
Bundle of His -->Perkinji Fibers-->Back to apex of the heart
73
Resting potential of pacemaker cells?
-60 mV
74
Resting potential of cardiac muscle cells?
-85 mV
75
What causes the spontaneous depolarization in pacemaker cells that passes to other cardiac cells?
Funny channels (I-f)
76
What are funny channels (I-f)
Non-selective cation channels that open at hyperpolarization and close upon depolarization. Allows Na+ to leak into the cell.
77
What is the cardiac cycle equivalent to?
A heart beat
78
What is the definition of a cardiac cycle/heart beat?
One complete sequence of heart contraction and relaxation
79
How long is a cardiac cycle?
0.8 sec
80
What is the contraction phase called?
Systole
81
What is the relaxation phase called?
Diastole
82
What happens in ventricular diastole?
Pressure in the atria exceeds ventricular pressure. The AV valves open and the ventricles fill passively
83
What happens in atrial systole?
Atrial contraction forces additional blood into ventricles
84
What happens in ventricular systole (Isovolumentric contraction)?
Ventricular contraction pushes the AV valves closed and increases pressure inside the ventricle
85
What is also known as ventricular systole (ventricular ejection)?
Increased ventricular pressure forces the semilunar valves open and blood is ejected
86
What happens in ventricular diastole?
As the ventricles relax, pressure in the arteries exceeds ventricular pressure, closing the semilunar valves
87
5 steps of the mammalian cardiac cycle
1. Ventricular diastole
2. Atrial systole
3. Ventricular systole (isovolumetric contraction)
4. Ventricular systole (ventricular ejection)
5. Ventricular diastole
88
What is SV?
Stroke Volume
89
What is stroke volume?
The amount of blood pumped by the left & right ventricles in each contraction.
90
What is the average stroke volume in humans?
0.07 Liters
91
What is CO?
Cardiac output
92
What is cardiac output?
The combined sum of output from the left & right ventricles during ventricle systole per minute
93
What are the units for cardiac output?
Liters of blood / minutes
94
What is HR?
Heart rate (beats/min)
95
What is CO equal to?
CO = SV * HR
96
What is the typical cardiac output?
~5 liters/min
97
What is the typical heart rate for a human?
72 beats/min
98
How much blood is pumped through the body in one minute?
ALL of it
99
How much does CO2 increase during exercise?
4-7 fold
100
What effect does the sympathetic nervous system have in the heart?
1. Stimulatory
| 2. Causes Na+, Ca2+ cellular influx-->Increased depolarizations-->Increased heart rate
101
What effect does the parasympathetic nervous system have in the heart?
1. Inhibitory
| 2. Causes increased K+ cellular efflux & decreased Ca2+ influx-->Decreased depolarizations-->Decrease heart rate
102
Where is the cardiovascular control center?
Medulla Oblongota
103
Molecular pathway of parasympathetic action on the heart:
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
Molecular pathway of sympathetic action on the heart:
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
Molecular pathway of parasympathetic action on the heart:
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
Molecular pathway of sympathetic action on the heart:
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
Explain in depth the Beta-1 mechanism at which sympathetic innervation of the heart occurs.
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
How do we measure the cardiac cycle?
EKG/ECG
109
Components of the EKG
P wave, QRS complex, T wave
110
What is happening during the P wave of an EKG?
Activation of the atria
111
What is happening during the QRS complex of the EKG?
Activation of the ventricles
112
What is happening during the T-wave of an EKG?
Recovery wave of ventricles (and atria?)
113
What type of fibrillation is fatal?
Ventricular fibrillation
114
What stimulates the P-wave?
SA node
115
What causes the delay between the P-wave and the QRS complex?
AV node
116
What causes the Q part of the QRS complex
Bundle of His
117
What causes the R&S part of the QRS complex
Perkinji Fibers
