Cardiac System/Blood Pressure (Topics 11-18) Flashcards
(272 cards)
1
Q
What are the 2 roles of the circulatory system?
A
- Transportation
- Oxygen, Carbon dioxide
- hormones - Regulates temperature
2
Q
What are the 3 things that the blood consists of?
A
- Plasma
- Buffy coat
- Red blood cells
3
Q
What is the percentage of the plasma?
A
55%
4
Q
What is the percentage of the buffy coat?
A
less than 1%
5
Q
What is the percentage of red blood cells?
A
45%
6
Q
Where are the platelets and white blood cells found?
A
buffy coat
7
Q
What are the 3 systems of the blood?
A
- Venous system
- Arterial system
- Pulmonary system
8
Q
What is the pressure in the pulmonary system?
A
low pressure
9
Q
What is the pressure in the arterial system?
A
high pressure
10
Q
What is the pressure in the venous system?
A
low pressure
11
Q
True or False
The arteries carry oxygenated blood
A
True, except for pulmonary arteries
12
Q
True or False
The veins carry deoxygenated blood
A
True, except pulmonary vein
13
Q
Why does the arterial system have a higher pressure?
A
The blood leaving the left ventricle has to pump oxygenated blood everywhere
14
Q
What are the 2 reasons the venous system has a lower pressure?
A
- For clean gas exchange (at the capillaries)
- Valves help get the blood back to the heart
15
Q
What is the interventricular septum?
A
muscular wall that divides the ventricles and contains the bundle of hiss
16
Q
Blood moves down pressure gradients, meaning the volume will do what when it contracts?
A
gets smaller, Boyle’s law
17
Q
True or False
Valves open passively
A
True
18
Q
Which kinds of values are classified as AV valves?
A
valves that separate the atrium and the ventricles
19
Q
Which kinds of values are classified as semilunar valves?
A
separates ventricles from arteries
20
Q
Why is the RIGHT AV valve different from the left AV valve?
A
RIGHT = valve is tricuspid
LEFT = valve is bicuspid
21
Q
Why are the left ventricular pressures 4 times bigger than the right?
A
because it pumps blood to the body
22
Q
True or False
The more cusps, the weaker the valve
A
True
23
Q
Which of the AV valves is stronger?
A
Bicuspid
24
Q
What is unique to cardiac muscle tissue compared to regular muscle tissue?
A
intercalated discs, which are desmosomes and a gap junction
25
What do intercalated discs allow for?
a wave of depolarization throughout the cardiac tissue to allow for coordinated contractions
26
How is the cardiac tissue stimulated?
via PNS and SNS
27
What does the PNS do for the heart, and how?
slows the heart rate down via the vagus nerve
28
What is our intrinsic heartbeat on average?
100 beats per minute
29
What does the SNS do for the heart, and how?
speeds heart rate up and can take over control
30
What is the order of myocontraction depolarization?
1. Atria
2. Ventricles
31
True or False
Each chamber does NOT contract at the same time, it uses waves of depolarization
True
32
What does the SA node stand for?
sinoatrial node
33
What does the AV node stand for?
atrioventricular node
34
What is the pacemaker of the cell?
SA node
35
Where does the depolarization start?
SA node
36
Where do the ventricular contractions start?
from the bottom
37
True or False
The atrium fully relaxes, and then the ventricles contract
True
38
True or False
The AV node slows down the wave of depolarization so the atria can fully contract before ventricular contraction
True
39
What counts as 1 cardiac cycle?
Atrial excitation + Ventricular excitation + Ventricular relaxation
40
How long is the conduction of the AV node? relatively?
approx 0.1 secs to a quarter sec
41
What is the SA node made of?
- bundle of cells
- kind of like a muscle and a nerve
- has an action potential
- starts the wave of depolarization
42
Can the SA node contract?
No, but it can depolarize
43
What does the intrinsic heart rate mean?
A self-excitatory system
44
Where does the Pacemaker potential occur?
SA node
45
In a resting state, is there more Na+ or K+ in the cells of the SA node?
K+
46
Is there Cl- in the resting cell of the SA node?
yes
47
What is the resting potential of the cells in the SA node?
-60
48
What is the value of the THRESHOLD potential in cardiac SA node cells?
-40
49
What is the peak of an action potential in an SA node cell?
+1 to +5
50
What determines the action potential in SA node cells?
how quickly or slowly the pacemaker potential occurs, which will determine our action potential frequency for 1 minute
aka determines heart rate
51
If the Pacemaker slope is steeper, what will the heart rate be?
steeper slope = increased action potential frequency, aka faster heartbeat
52
What does decreased permeability refer to?
The channel is closing!!
53
Why are the T-type channels slow?
We want to make sure our heart rate is not too fast
54
At the threshold what is occurring in the SA node cell?
T-type Ca2+ channels close
L-type Ca2+ channels open
*allows an action potential to occur
55
What do L-type calcium channels allow for?
The big and faster influx of calcium, called long-type calcium channels
56
What is happening at the peak of the action potential?
- Calcium channels close
- K+ channels open to repolarize the cell!
57
What changes in the cardiac action potential cycle as our heart rate increases?
Pacemaker potential will most likely be steeper
58
True or False
The slope of the pacemaker potential will determine the rate of action potential generation, aka the heartbeat
True
59
What is the main source of the action potential in the SA node cells?
calcium concentration
60
How do we decrease our heart rate?
parasympathetic stimulation
61
How do we increase our heart rate?
sympathetic stimulaiton
62
The initial increase in heart rate starts from what?
The withdrawal of the parasympathetic stimulation
63
In the case without the SA node, will the AV node have its own pacemaker rate? If so, what will it be?
Yes, 25-40 action potentials per minute
64
True or False
In a normal healthy person, the AV node has its pacemaker but is stimulated by the SA node for unison heartbeats
True
65
What does Arithmia mean?
When there is no unison/consistency in the SA node stimulating the AV node
66
How can we pace the ventricles if there is some sort of lost connection between the SA node and the AV node?
Pacemaker
67
How do pacemakers work?
They will have an external body machine with wires that go into the heart, in the right atria and ventricles to stimulate the cardiac tissue, acting as the SA and AV node
68
What are the full steps of an action potential in the pacemaker cells?
The cell begins at -60 mv
K channels are closed
- making cells more positive as K cannot leave
- F-type Na channels open depolarizing
- T-type Ca channels open depolarization
Pacemaker potential is met at -40mv the action potential now occurs:
- triggers L-type Ca channel to open
- a big influx of Ca into the cell
- all other channels close
- cell reaches 0
The cell restores the resting membrane potential
- K channels open again
- L-type Ca channels now close
69
Are cardiac muscle cells autorhythmic or non-autorhythmic?
non-autorithmic
70
What is regulating the pace of the heart?
SA node
71
What do the cardiac cells do?
- They receive a signal
- Then they initiate a contraction that is going to happen in the cardiac muscle
72
What is the primary purpose of cardiac muscle?
contraction
73
What is the membrane potential range? (FULL RANGE IE GRAPH)
-90 to +30
74
What is the resting membrane potential in a cardiac muscle cell?
-90 mv
75
What value is the threshold potential for action potentials in a cardiac muscle cell?
-70
76
Why is the resting membrane potential for cardiac muscle cells -90 mV?
because the resting membrane is very permeable to K+, K+ channels are open
77
What regulates the resting cells' ion (K+, Na+) concentrations?
Sodium-Potassium pump
78
What happens when we have a “leaky K+” channel?
The cell becomes more negative as we are losing positive ions
79
What is the key ion that maintains the rest of the membrane potential in cardiac cells?
K+
80
In resting membrane cells, which ion begins to initiate a rise in the resting membrane potential? (Going from -90 and getting to a less negative number)
sodium
81
How does Na+ come into the CARDIAC MUSCLE cells?
via the gap junctions
82
Na+ permeability describes what kind of feedback process?
positive feedback
83
What are the 3 phases in Cardiac Action Potentials?
1. Atrial/Ventricular action potentials
2. Membrane depolarization and plateau phase
3. Membrane repolarization
84
IN CARDIAC MUSCLE
At the membrane depolarization and plateau phase, what is the permeability for Na+, K+ and Ca2+?
1. Decreased Na+
2. Increased Ca2+
3. Decreased K+
85
IN CARDIAC MUSCLE
How does Ca2+ start increasing in the cell?
via voltage-gated calcium channels
- Detecting the voltage change in the membrane due to the previous influx of sodium
86
IN CARDIAC MUSCLE
What is the voltage-gated Ca2+ channel called that is open at the plateau phase?
L-type Ca2+ channel
- stays open for a LONG time
87
IN CARDIAC MUSCLE
Via the L-type Ca2+ channel, how fast does the Ca2+ move into the cell?
Not fast, VERY SLOW
88
IN CARDIAC MUSCLE
What is happening at membrane repolarization?
- Ca2+ channels close
- K+ rapidly leaves the cell
89
IN CARDIAC MUSCLE CELLS
What is responsible for the slow movement of the Ca2+? (THE DIP IN THE GRAPH, plateau phase)
There is a balance between the Ca2+ moving into the cell and the K+ ions moving outside of the cell
90
IN CARDIAC MUSCLE CELLS
To repolarize the cell, K+ will rapidly leave the cell until the cell gets back to what?
-90 mV, resting
91
What is the time that it takes to start and end a CARDIAC action potential?
250
92
In Atrial muscle cells, what is the time it takes for a full action potential to occur?
150
93
What are the 4 STEPS involved in the process of Excitation-Contraction Coupling
1. Membrane depolarization
- action potentials down T-tubules
2. Entry of Ca2+ into the cell
-through L-type Ca2+ channels
3. Ca2+ binds to the ryanodine receptor and regulates the exit of Ca2+
4. Increase Ca2+ being stored in the sarcoplasmic reticulum
- gets released into the cytosol (via calcium-induced calcium release
- Ca2+ will initiate contraction of the actin and myosin
- Ca2+ is pumped back into the sarcoplasmic reticulum (via SERCA)
94
What is the role of the sarcoplasmic reticulum?
store calcium
95
True or False
The cardiac muscle cell regulates Ca2+ entry into the cell
True
96
How could we calculate the max heart rate given the refractory period being 250 ms?
4 possible action potentials that can happen in one second
4 x 60 = 240 beats per minute
97
IN CARDIAC MUSCLE CELLS
How long is the refractory period?
250 ms
98
What is the primary purpose of the plateau phase of the CARDIAC action potential?
To cause Ca2+ induced-Ca2+ release
- The primary purpose is to cause contraction
99
What are all 5 steps involved in creating an action potential in cardiac cells?
1. Sodium influx from gap junction
- membrane reached -70 threshold potential
- K channels are closed
2. Sodium influx from voltage-gated channels
- membrane reached +30 then closes
- positive charges travel down the membrane doing two things:
( i ) activates K transient channels
( ii ) activates Ca L-type channels
3. K efflux and Ca influx
( i ) repolarizes cell
( ii ) allows for excitation-contraction coupling via calcium-induced calcium release
4. K efflux
- all channels are closed
- after muscle contraction K voltage channels open getting the cell back to the resting membrane
5. Leaky K channels open
- everything else is closed
100
What is responsible for the dip in the graph after the peak?
Increased K permeability as K transient channels open, trying to repolarize the cell
101
What are the 2 factors responsible for the plateau part of the graph?
1. K leaky and transient channels are open but trying to close
2. Ca L type is open
meaning K leaving the cell in counteracting Ca entering the cell
102
What are the 2 consequences of high systolic blood pressure?
1. Aneurysm
2. Myocardial infarction - heart attack
103
What does a perfect storm refer to?
If you have high BP and atherosclerosis, and you are elderly, doing some kind of exercise, you risk dying from a heart attack
104
What causes an aneurysm?
High Blood pressure
105
What is an aneurysm?
a rupture of the wall of the aorta, causing blood to leak into the body cavities
106
What does it mean to have an abdominal aneurysm?
The aorta is stretched out, without being able to recoil back
107
True or False
Aneurysms are caused by high BP, hypertension, and as we go through the various phases of hypertension, it causes more and more stress and stretch of the aorta
True
108
What is an aortic dissection?
Theres a weak point of the aorta, which causes it to burst
109
Do aneurysms occur in young people?
No, not typically, not unless you have Marfan's syndrome
110
What are the 2 types of aneurysms?
1. Abdominal aorta aneurysm
2. Aortic dissection
111
Are abdominal aorta aneurysms more common in males or females?
males
112
What is Marfan Syndrome? aka Spiderman syndrome
It is a mutation in the extracellular matrix protein, "fibrillin-1"
113
What is fibrillin-1?
a protein that attaches elastic and non-elastic tissues to a structural membrane
- kind of like connective tissue
114
What are the characteristics of an individual with Marfan's Syndrome? What do they look like?
- tall
- thin
- arm span exceeds their height
- long fingers
- stretchy skin with poor recoil
*Depending on the severity of the disease, they could have a caved-in chest
115
What does the aorta look like for an individual with Marfan's syndrome?
- Elastin fibres are disorganized
- high risk or aortic aneurysm
116
What is a myocardial infarction?
The workload being done by the heart is too high and it is not met by the oxygen supply, which leads to cardiac death
117
True or False
To maintain cardiac output when aortic pressure is elevated, the left ventricle must contract harder to meet oxygen demand
True
118
When Mean Arterial Pressure increases, what happens to the stroke volume?
Stroke volume decreases
119
What is "afterload"?
pressure distal to the ventricles in which the heart was working against to allow blood flow to occur
120
True or False
Ventricular ejection can only occur when left ventricular pressure is greater than the aortic pressure
True
121
Why is the stroke volume decreased in the case of high BP or hypertension?
Due to the shorter ventricular ejection duration!!
122
How does the heart compensate for lower stroke volumes?
Left ventricle contracts strongly, to develop higher LVP
SNS detects a lack of O2 and stimulates the left ventricle
123
What is the chain of IMMEDIATE consequences for increased Mean arterial pressure?
decreased stroke volume
-
decreased coronary blood flow and decreased oxygen delivery
-
Oxygen deprivation to cardiac myocytes
124
What is the chain of events for Compensation?
increased left ventricular contractility (so stroke volume is maintained)
-
increases oxygen demand and decreases coronary blood flow (due to longer systole vs diastole
-
Oxygen deprivation to cardiac myocytes
125
What is cardiac ischemia?
When there is a blockage in the arteries of the heart (coronary artery) due to plaque of some sort, it reduces the amount of blood flow to the heart
126
Why would a prolonged systole and a shortened diastole lead to an impaired blood supply to the heart?
High ventricular pressure during systole compresses the arteries, reducing the coronary blood flow temporarily, along with a shortened diastole, not allowing enough time for blood to flow through the coronary arteries
127
Where would the coronary arteries be compressed the most?
endocardium, the deepest layer of the heart
128
During a myocardial infarction, what is occurring with blood flow?
decreased blood flow during systole, which leads to:
- decreased oxygen to myocytes
- could lead to a decrease in ATP
- Myocytes cannot repolarize or relax (causing an ST-segment plateau)
- myocardial infarction
129
A plateau in the ST segment is caused by what?
myocardial infarction
130
What is atherosclerosis?
Blocking blood delivery to the heart in the lumen of the arteries
131
What are examples of blockages that cause atherosclerosis?
- saturated fats
- plaque formation
- cholesterol
132
What is a thrombus in reference to atherosclerosis?
plaque that is emobile, aka stuck to the wall of the lumen
133
What is an Embolus in reference to atherosclerosis?
plaque that is mobile and moves through the arteries
134
What are the 3 factors in the "Perfect Storm"?
1. Atherosclerosis forms
2. Hypertension
3. Exertion or exercise of some sort, aka O2 demand
ALL LEAD TO INSUFFICIENT BLOOD SUPPLY TO MYOCYTES
135
What are the 3 consequences of the "Perfect Storm"?
1. Myocardial infarction
- heart attack
- leads to death
2. Cardiomyocyte dysfunction
- Impairment in certain parts of the heart
- weakness of the heart, chronic
3. Congestive heart failure
- fluid accumulating in the heart
- weakness of the heart, chronic
136
What is an ECG signal?
The sum of all cardiac action potentials
137
Where do we get cardiac action potentials from?
SA node and cardiac muscle cells
138
Where does the electrical activity come from predominantly?
cardiac muscle cells
139
What happens at the P-wave?
Atrial depolarization
140
What happens during the PR wave?
contraction, atrial contraction and AV delay
141
How long is the P-wave typically?
200msec
142
True or False
The longer the amplitude of the signal = the more cardiac muscle cells will be activated
True
143
What is Q representing?
a lag/delay in time due to AV nodal delay
144
What is the purpose of the Q stage?
to ensure that the atria fully contract and can fully eject the blood from the atria into the ventricles before the ventricles contract
145
What is the QRS?
ventricular depolarization
146
True or False
Ventricular contraction occurs quickly
True
147
Why is QRS all happening so rapidly?
Due to Purkinje fibres, they can’t wait for cell-to-cell conjugation; therefore, it needs to happen quicker
148
Why is there a larger amplitude in ventricular electrical activity compared to the atria?
It is stronger because there are more cardiac muscle cells
149
True or False
More cardiac muscle cells = more electrical activity
True
150
What is happening between the S and T segments?
ventricular contraction ejects blood into the aorta or pulmonary artery
151
What is happening at the T-wave?
ventricular repolarization
152
What is happening at the T-P interval
ventricular relaxation
153
Why is atrial repolarization not seen in the ECG image?
We cannot see it because it is dominated by the RS wave generated by ventricular depolarization
154
During the ECG recording, let's say that the QRS is seen to be smaller than normal. What is most likely the physiological explanation for this change in amplitude?
due to smaller and thinner ventricles, because cardiac muscle cells are responsible for generating electrical activity, meaning fewer cells will equal less activity
155
What is Extrasystole?
premature ventricular contraction
156
What is ventricular fibrillation?
When there is no QRS consistently, the ventricle is not depolarizing sufficiently to pump enough blood into the body
- The ventricle can’t pump blood properly
157
What can fix ventricular fibrillation?
paddles
158
What is complete heart block?
- SA node is working properly, meaning the P-wave is depolarizing at a regular sequence
- QRS is present, so the ventricle is depolarizing
- AV node is working
- Communication between SA and the AV node is lost
159
What is a Myocardial infarction, aka a Heart Attack?
- ST elevation
- due to a clot, there is not sufficient oxygen, and depolarizations are off-sync
160
Do we need a pressure difference to move blood in the body?
yes
161
What are the 2 important phases of the cardiac cycle?
1. Systole
- ventricular contraction and ejection
2. Diastole
- ventricular relaxation and filling
162
What is an isovolumetric ventricular contraction?
- Same volume contraction
- meaning there is no volume change in the heart, but the heart is contracting
163
True or False
In isovolumetric contraction, are all the valves always closed?
True
164
What is happening with pressure in the isovolumetric ventricular contractions?
- The ventricle has greater pressure than inside the atria
- Pulmonary artery pressure or aortic pressure is greater than ventricular pressure because the ventricular pressure is not sufficient to open the pulmonary or aortic valve
165
What is happening during isovolumetric relaxation?
- All the valves are closed
- The ventricle is relaxing
- Pulmonary and aortic pressure is still higher than inside the ventricle
166
What is the step that follows isovolumetric relaxation?
Ventricular filling, where blood flows into the ventricles
167
What is happening during ventricular filling?
After the heart has had a ventricular contraction
- Now, the ventricle is an area of low pressure
- Atrial pressure is higher than the ventricular pressure, causing ventricular filling
The AV valve is opened
168
What is the time associated with systole?
0.3 sec or 300 msec
169
What is the time associated with diastole?
0.5 sec or 500 msec
170
How can we calculate stroke volume?
end diastolic volume - end systolic volume
171
STEP 1
What is happening at Ventricular diastole?
Blood comes into the heart through the atria
- AV valves sense the high pressures in the atria, forcing them to open to allow for blood to flow into the ventricles
- SA node signals atria to contract any remaining blood from the atria to the ventricle
P wave
172
STEP 2
What is happening at Isovolumetric systole?
All the blood is in the ventricles now, all the valves are shut
- Ventricles go through an isovolumetric contraction as pressure builds
QRS complex
173
STEP 3
What is happening at ventricular systole?
Pressure is built in the ventricles
- Semilunar valves open
- Blood is being pushed into the aorta or pulmonary arteries
QRS complex
174
STEP 4
What is happening at Isovolumetric diastole?
Blood is going to the rest of the body or the lungs
- All valves are shut again
- Ventricles are relaxing
T wave
175
How is the heart rate regulated?
PNS and SNS
176
What are the 3 factors regulating the stroke volume?
1. Cardiomyocyte length-tension relationship
2. Frank-Starling mechanism
3. SNS
177
What is the default pacemaker heart rate?
100
178
What is the average person's resting heartbeat?
70
179
What are the units of stroke volume
ml/beat
180
Does our cardiac output increase when exercising?
Yes, both HR and SV will increase
181
What is the negative regulator of the heart rate?
PNS
182
What is a positive regulator of the heart rate?
SNS
183
What are the 2 positive regulators of stroke volume?
1. Extrinsic control
- SNS
2. Intrinsic control
- end diastolic volume
184
True or False
If we increase SNS activity, that will increase venous return,n which will increase end-diastolic volume
*What kind of feedback loop is this?
true, positive feedback loop
185
Which kind of cells have autorhythmic potential?
SA and AV node cells, pacemaker cells
186
Which kind of cardiac cells are non-contractile?
SA and AV node cells
187
Which cardiac cells regulate stroke volume?
Cardiac muscle cells
188
Which cells regulate heart rate?
SA and AV node cells
189
Is stroke volume dictated by changes in action potential?
No, it is dictated by changes in the excitation-contraction coupling (specifically changes in calcium)
190
To slow or increase the heart rate, we need to change what?
pacemaker activity
191
From an Ion perspective:
How does the PNS slow down the heart rate using ions?
- Increase the amount of K+ efflux (pushing K+ outside of the cell), which will drive the membrane potential negative
Ie, making it further away from the threshold potential
- Decrease the amount of Na+ influx into the cell (keeping sodium ions outside of the cell), making it more negative
- Decrease the amount of Ca2+ entering the cell
192
With PNS, does the threshold potential change?
No
193
How does the PNS slow the heart rate down? What does it use?
increased acetylcholine
194
How does the SNS speed up the heart rate? What does it use?
increased norepinephrine and epinephrine
195
From an Ion perspective:
How does the SNS speed up the heart rate using ions?
- increase the influx of Na+ and Ca2+
- More sodium from outside the cell is going into the (negative) inside the cell, and more Ca goes through the T-type calcium channel
- Much faster rise in the resting membrane potential towards the threshold potential
196
True or False
PNS and SNS are only changing the pacemaker potential
True
197
What is the difference between the PNS and SNS when it comes to speeding up and slowing down the heart rate?
PNS affects K+ as it increases the efflux of K+
198
Can we have both PNS and SNS “on” at the same time about affecting the heart rate?
yes, they can both be on however, one will be more dominant at any given time
199
What is the key regulator of stroke volume?
Cardiac muscle cell, ventricular contraction
How much blood is being pumped out of the heart
200
What is the intrinsic control that regulates stroke volume?
end-diastolic volume
201
True or False
Stroke volume is determined mainly by end-diastolic volume + venous return
True
202
When our muscles are stretched, are we going to have lots of cross-bridges forming? Why or why not?
- NO
- Actin and myosin are stretched apart, and therefore, there is not much overlapping of the two
203
What does the Frank-Straling Mechanism represent?
What does the Frank-Straling Mechanism represent?
204
When our muscles are shortened, are we going to have lots of cross-bridges forming? Why or why not?
- NO
- Now the actin filaments are overlapping with fellow actin and therefore hide the active sites for the myosin to interact
205
What are the x and y axis for the length-tension relationship of cardiac muscle?
x-axis: End-diastolic volume
y-axis: Stroke volume
206
Can we ever overly stretch the heart?
No, not possible
207
If we use the SNS to increase the Calcium release in every cardiac muscle cell, what happens to the stroke volume?
increase the amount of Ca2+ entering the cell via the L-type calcium channel, which releases more calcium to bind the Ryanoide receptor, thus increasing more calcium, causing the stroke volume to increase
208
The contraction time in the heart goes from ________ to _______ with stimulation of the SNS
300ms to 250ms
209
What are the 7 functions of the vascular system?
1. Delivery of oxygen
2. Removal of oxygen
3. Nutrient delivery
4. Removal of waste
5. Distribution of hormones
6. Transport of immune cells
7. Temperature control
210
What is the MAIN function of the vascular system?
Delivery of oxygen
211
What is the cell called when we can not remove the carbon dioxide?
acidosis, which means it impairs cell function
212
What is the percentage of blood that goes to the skeletal muscles at rest?
15%
213
What is the percentage of blood that goes to the digestive system at rest?
21%
214
What is the percentage of blood that goes to the Kidneys at rest?
20%
215
What are the 2 components of the vascular network?
1. Pulmonary
- involves the heart and lungs
2. Systemic
- involves the heart and tissue
216
What does macro circulation do?
takes blood to or from organs
217
What does micro-circulation do?
distributes blood within each organ
218
What are 3 examples of microcirculation?
- systemic capillaries
- venules
- arterioles
219
What are 4 examples of macrocirculation?
- aorta
- systemic veins
- pulmonary artery
- pulmonary veins
220
What forms the inner layers of ALL blood vessels?
Endothelial cell
221
Arterioles have the same components to make up their composition as arteries, except for what?
elastic fibres
222
What are the ONLY 2 components that make up capillaries?
1. Endothelial cells
2. Basement membrane
223
What are the 5 layers that make up the veins?
- Venous valves
- Endothelial cells
- Basement membrane
- Smooth muscle, elastic fibres
- Connective tissue, mostly collagen fibres
224
What are the 5 layers that make up the arteries?
- Endothelial cells
- Basement membrane
- Elastic fibres
- Smooth muscle
- Elastic fibres
- Connective tissue, mostly collagen fibres
225
True or False
Veins have lower pressures than arteries?
True
226
Flow can be replaced with what in vascular research?
Q
227
Right arterial pressure generally always equals what?
0
228
What determines blood flow?
delta pressure
229
True or False
The highest pressure is the systolic pressure, and the lowest pressure is the diastolic pressure
True
230
Why can the pressure in the heart go to 0, but the pressure in the larger arteries only go to approximately 80?
because the arteries will always have blood flowing in it flowing
231
Where is the largest pressure drop?
at the arterioles
232
Why is the MAP so important? What are its 3 main purposes?
1. Contributes to the Heart's workload
2. Provides driving forces to move blood
3. The number 1 regulated thing in our body
- otherwise impaired nutrients and oxygen
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What does hypotension refer to?
low blood pressure
234
What are our systolic BP and diastolic BP for hypotension?
90/60 mm Hg
235
What are the 4 main symptoms of hypotension?
1. Dizziness
2. Fainting
3. Blurred vision
4. Fatigue
236
What causes these symptoms of hypotension?
- Insufficient blood flow to the brain and muscles
- resulting in insufficient oxygen distribution
237
What are the 4 causes of hypotension?
1. Dehydration
2. Pregnancy
3. Heart failure
4. Anemia
238
What are the 3 risk factors for hypotension?
1. Age
2. Medication
3. A certain disease
239
Why would Parkinson’s disease lead to low blood pressure?
It affects the autonomic nervous system, aka PNS and SNS, to regulate blood pressure
240
Is Hypotension or Hypertension known as the silent killer?
Hypertension
241
What does hypertension refer to?
High blood pressure
242
What are the ranges of systolic and diastolic BP in stage 1 of hypertension?
130-139/80-89 mm Hg
243
What are the ranges of systolic and diastolic BP in stage 2 of hypertension?
> =140/>=90
244
What are the ranges of systolic and diastolic bp in stage 3 (Hypertensive crisis) of hypertension?
> 180/>120 EMERGENCY
245
What are the 6 severe symptoms of hypertension?
1. Stroke
2. Heart Attack
3. kidney failure
4. Blindness
5. Dementia
6. Sexual dysfunction
246
What are the 4 causes of hypertension?
1. Atherosclerosis
2. Kidney disease
3. Sleep apnea
4. Thyroid issues
247
What are the 8 risk factors for hypertension?
(most are modifiable)
- age
- genetics
- obesity
- inactivity
- smoking
- high sodium intake
- stress
- alcohol consumption
248
Conduit vessels refer to what?
Arteries
249
What is the function of an artery?
takes blood from the heart and distributes it to the various organs/tissues
250
What are 2 ways that blood flow moves efficiently?
1. Minimize the resistance
- larger diameter
- low contractility, smooth muscle
- high compliance, elasticity
2. Artery walls need to be STRONG
251
In a rested state, how much blood do we have in the aorta during systole? And how long does it last?
75 ml, 0.3 seconds
252
Is the stretch of the aorta when blood comes into it passive or active?
passive
253
During systole, the aorta and heart will do what?
aorta = expands passively
heart = contracting and emptying
254
During diastole, the aorta and heart will do what?
aorta = recoils passively
heart = relaxing and filling
*The aortic valve is shut, meaning blood has to move forward
255
What are the 2 Major benefits of compliance?
1. Lowers systolic blood pressure
- via stretching, more volume, more space to go
2. Converts intermittent flow into continuous blood flow
- aka Windkessel effect
256
What is the Windkessel effect?
helps to dampen the fluctuations in blood pressure over a cardiac cycle and maintains continuous blood flow when ventricular ejection ends (diastole)
257
What allows aortic compliance?
elastin
258
What is elastin?
matrix protein that increases compliance
259
Where can elastin be found?
arteries and tissues
260
If we want high compliance, what would need to increase the volume or the pressure?
volume
261
If we want low compliance what would need to increase the volume or the pressure?
pressure
262
What is pulse pressure?
It is the pressure that dictates the movement of blood flow through the systemic circulation
263
What does the Aortic valve closure refer to?
dicrotic notch
264
What are the 3 factors that regulate the Pulse Pressure?
1. Stroke Volume
2. Speed of blood ejection into the aorta
3. Aortic compliance
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How does stroke volume affect Pulse pressure?
- Increased stroke volume will lead to increased systolic blood pressure
- more pressure, more heart contractility, which leads to increased pulse pressure
266
How does the speed of the blood ejection into the aorta affect Pulse pressure?
- If the heart is contracting more, that will increase the speed, as well as increase the heart rate will all cause increased contractility
- Increased contractility will cause increases in systolic blood pressure, which leads to increased pulse pressure
267
How does the aortic compliance affect the Pulse pressure?
- More compliant aorta will drop systolic blood pressure
- Reduce systolic blood pressure, which will decrease Pulse pressure
268
When we age, which pressure will increase a bit more?
systolic blood pressure
269
Why would aging affect our pulse pressure?
aorta becomes less compliant, elastin properties will deteriorate
270
What happens to our blood pressure during weightlifting?
- A drastic increase in mean arterial pressure
- Double or three times during resistance exercise
271
Why does our MAP, and systolic blood pressure increase as we weight lift?
Exercise pressor reflex
272
What is the exercise pressure reflex?
- We generate lots of tension in our skeletal muscles
- High tension can activate mechanoreceptors inside our muscles as well as metabolite receptors
- The high tension generated in your fibres will accumulate lactate, and that will activate muscle afferents
- That will generate an autonomic response to increase SNS and drop PNS, aka increase stroke volume and increase vasoconstriction to other places that do not need lots of blood flow
- All increasing systolic blood pressure
