Cardiovascular System- Unit 1 Flashcards
1
Q
During what week does the heart start beating in the womb?
A
3rd or 4th weeks
2
Q
About how many times will our heart beat in our life time?
A
3 billion
3
Q
The right side of the heart receives oxygen—–blood from the —— circulation and pumps the blood to the —–.
A
poor, systemic, lungs
4
Q
The left side of the heart receives oxygen—– blood from the ——- and pumps it to the——-.
A
Rich, Lungs, rest of the body
5
Q
The part of the circulatory system that pumps blood to the lungs is called —-.
A
Pulmonary Circulation
6
Q
The part of the circulatory system that pumps blood to the body is the—-.
A
Systemic Circulation
7
Q
Two receiving chambers of the heart are called
A
Atria
8
Q
Two pumping chambers of the heart
A
Ventricles
9
Q
Where does the right atrium receive blood from and what type of blood is it?
A
Oxygen poor blood form the systemic
10
Q
The left atrium receives —blood from the —-
A
oxygen rich blood from the pulmonary
11
Q
blood goes from the right atrium to the—– and then pumps into the —–
A
Right ventricle, Lungs
12
Q
Is the right side of the heart a high or low pressure system?
A
Low
13
Q
The right side of the heart seldom produces pressure above —–mmHg
A
40
14
Q
Blood from the left atrium flows to the —– which pumps blood into the —— circulation.
A
Left ventricle, Systemic
15
Q
What arteries supply the heart with oxygen full blood?
A
Coronary arteries
16
Q
Is the left side of the heart a high pressure or low pressure system?
A
High pressure
17
Q
The left side of the heart regularly produces pressures of around—– and during times of physical stress can produces pressure over—–
A
120, 200
18
Q
What is the purpose of heart valves?
A
to ensure that the blood moves efficiently through the heart
19
Q
What is it called when a valve pushes back into the atria when the ventricles contract?
A
Prolapse
20
Q
Which types of valves balloon?
A
Semilunar valves
21
Q
Which valves require support from other structures to prevent prolapse?
A
AV valves
22
Q
What is valvular Stenosis?
A
a heart murmur that occurs when the valve becomes too stiff
23
Q
What is the art of listening to body sounds with a stethoscope called?
A
Auscultation
24
Q
What is Valvular Regurgitation?
A
a heart murmur caused by a valve not closing properly.
25
Are all murmurs due to valve disease?
No, It is not uncommon to detect murmurs in young, thin individuals or during times of greatly increased blood flow as would occur during strenuous physical activity.
26
What is the sack around the heart called?
Fibrous Pericardium
27
What two membranes does the Fibrous Pericardium contain?
The parietal and visceral pericardium
28
Are the parietal and visceral pericardium connected?
No
29
What is in-between the parietal and visceral pericardium that allows them to move independently of each other
Pericardial fluid
30
Why would it be bad if excess fluid entered the pericardial space?
It could compromise efficient pumping of the heart
31
What is cardiac Tamponade?
When excess fluid enters the pericardial space
32
What three layers make up the wall of the heart?
Epicardium, Myocardium, and the endocardium
33
What makes up the epicardium?
the visceral pericardium and the outer surface of the heart
34
What is the myocardium?
The muscular layer of the heart
35
what is the endocardium?
the squamous cells that line the inner surface of the heart
36
what are found on the inner surface of the heart chambers that make it look rough in appearance?
Trabeculae
37
What is Trabeculae
Beams of tissue covered by endocardium
38
Cardiac muscle, like skeletal muscles is a type of ----- muscle.
Striated
39
Cardiac muscle cels are much------ than skeletal muscles, and they are -------.
Smaller, branched
40
What end to end special structure connects muscles cells together?
Intercalated discs
41
What are found inside of intercalated discs that tightly connect the cells together?
Desmosomes
42
What causes the heart to contract?
When they contract they all pull against each other causing the diameter of the chambers to decrease, which generates the pressure necessary to pump the blood
43
Where are gap junctions found?
In the intercalated discs
44
What is the function of Gap junctions?
allows communication between the cells including the movement of cytoplasm, and ions, between the cells, effectively lowering the resistance, and more importantly, this allows action potentials to spread from one cell to the next.
45
What is functional syncytium?
When the millions of cells in each chamber act function as one cell.
46
Is the arrangement of sarcomeres more ordered in a skeletal muscle or a cardiac muscle?
Skeletal muscle, making the striations in cardiac muscle less distinct
47
Where is the nucleus on a cardiac muscle and what shape is it?
Cardiac muscle cells have a single nucleus located roughly in the center of the cell.
48
The t-tubules in cardiac muscles are ----- in size, and branch --------- within the cell
Large, longitudinally
49
The sarcoplasmic reticulum is ------ extensive in cardiac muscle
less
50
Cardiac muscles have ----- mitochondria making up a ------ of the intracellular volume.
more, third
51
Why do cardiac muscles have more mitochondria?
Because cardiac muscle cells derive all of their energy from aerobic respiration
52
What percentage of oxygen does the heart extract as blood passes through the coronary arteries?
70-80%
53
What is the only way from cardiac muscle to get more oxygen?
to increase blood flow to the muscle
54
Cardiac muscles can use ----- as an energy source, but would rather use-----, but can also use---- during exercise
Glucose, energy rich fatty acids, lactate (lactic acid)
55
What percentage of oxygen does a skeletal muscle at rest extract form the blood?
25%
56
What triggers the contraction of cardiac muscles
Action potentials
57
How long does the plateau phase of a cardiac action potential prolong the action potential?
as long as 300 milliseconds
58
What 3 ions play a role in a cardiac action potential?
Na+, K+, Ca2+
59
What is the cardiac Resting membrane potential (RMP)
around -90mV
60
What causes the low RMP of the cardiac cell action potential?
A special group of K+ channels that open when the membrane depolarizes and close wen the membrane repolarizes.
61
Why don't we see undershoot on a cardiac action potential?
Because the RMP is already essentially the lower limit
62
At stage 4 of a cardiac action potential, is K+ entering or leaving the cell?
Leaving making a lower RMP
63
What is another name for Phase 0 of a cardiac action potential?
Depolarization phase
64
What causes stage 0 of the cardiac action potential to occur?
The opening of a voltage-gated Na+ channel and the influx of Na+ rushing into the cell. The K+ channels from phase 4 also close
65
What is another name for Phase 1 of an action potential?
Rapid repolarization
66
What initiates the start of Phase 1 of the cardiac action potential?
At the end of phase 0 the Na+ voltage gated channels close stopping the influx of Na+ from flowing into the cell, and at the same time a small number of K+ channels open and start to repolarize the cell.
67
What is another name for phase 2 of the cardiac action potential?
Plateau
68
Which phase distinguishes a cardiac action potential from other action potentials?
Phase 2
69
What causes phase two of a cardiac action potential to occur?
Voltage gated Ca2+ channels open and Ca2+ starts to enter the cell. More K+ channels also open at this time and the influx of Ca2+ entering the cell negates the effects of K+ leaving the cell keeping the membrane potential constant.
70
What is another name for phase 3 of a cardiac action potential?
Repolarization
71
What causes the end of phase 2 and the start of phase 3 of a cardiac action potential?
During phase 2, more and more K+ channels continue to open and eventually the efflux of K+ leaving the cell is greater than that of the Ca2+ entering the cell so the membrane begins to repolarize. causing the Ca2+ VGC to close and the membrane returns to RMP and ALL OF THE K+ CHANNELS CLOSE EXCEPT THOSE MENTIONED IN PHASE 4. The phase 4 K+ channels open as the membrane repolarizes.
72
How many different types of K+ voltage gated channels are involved in the cardiac action potential?
At least 4 types
73
What are 2 important outcomes of the prolonged nature of the Cardiac action potential?
1. Prevents the muscle from restimulating until the muscle has had time to contract and relax
2. contraction of cardiac muscle requires the contribution of extracellular Ca2+. All during the plateau phase Ca2+ is entering the cell from the extracellular fluid, contributing to total intracellular calcium concentration.
74
How long does the absolute refractory period last for a cardiac muscle cell?
Until the last membrane repolarizes
75
What would happen if there was no plateau phase and our heart entered a state of tetany when the muscles remain continually contracted?
Blood flow would stop since relaxing is required to refill the chambers with blood.
76
What is an auto-rhythmic cell?
a cell with the ability to spontaneously initiate their own action potentials
77
How many phases are there in autorhythmic cells action potentials?
3 phases, Phase 4,0, and 3.
78
Is there a resting phase in autorhythmic cells?
No, once the membrane repolarizes it begins to slowly depolarize.
79
When do funny channels open and close?
They open when the membrane repolarizes and close when the membrane depolarizes.
80
What is another name for the "funny channels"
HCN channels- hyper polarized activated- cyclic nucleotide gated channels
81
Why are funny channels called hyper polarized activated-cyclic nucleotide gated channels?
because they open when the membrane hyperpolarizes and they can be regulated by the second messanger cyclic AMP, a cyclic nucleotide
82
What happens during phase 4 of an auto rhythmic cell action potential?
The funny channels allow Na+ to slowly enter the cell resulting in a gradual depolarization of the membrane
83
What is the gradual depolarization of an autorhythmic cell membrane due to the leaking of Na+ through the funny channels called?
Pacemaker potential
84
In autorhythmic cells, reaching threshold triggers the activation of voltage gated ----- channels which causes the ----------- of the cell membrane also known as phase 0
Ca2+, depolarization
85
What happens during phase 0 of an auto rhythmic cells action potential?
Ca2+ voltage gated channels are open and calcium is entering the cell causing the cell membrane to depolarize
86
At the end of phase 0 and the start of phase 3 in an autorhythmic action potential, what happens?
The voltage gated calcium channels close and the voltage gated K+ channels open.
87
What happens during phase 3 of an auto rhythmic cell action potential
K+ channels are open and the efflux of K+ out of the cell causes the repolarization of the cell membrane
88
What happens when the autorhythmic cell repolarizes and reaches threshold again?
K+ channels close and funny channels reopen to start the process over.
89
How long does it take an auto rhythmic action potential to occur?
about 800 msec
90
Where is the resting membrane potential for an autoRhythmic cell action potential
About -60mV
91
Why does the heart need its own specialized conduction system and what type of cells is it equipped with?
Conduction through gap junctions and intercalated disks are very slow and can't ensure the heart will beat in time or sequence. Non-contractile cardiac muscle cells make up this system.
92
What aids the slow conducting cardiac cells in spreading the action potential from the right atria to the left atria?
Bachman's bundle
93
Can an action potential spread directly from the atria to the ventricles on their own?
No, they are only connected by the cardiac skeleton made of connective tissue.
94
how is the action potential passed from the atria to the ventricles?
Through the AV node on the floor of the right atrium next to the interatrial septum
95
What carries the action potential from the SA no directly to the AV node?
internodal pathways
96
Why does the AV node delay the action potential for .15 seconds?
To allow the atria to contract before the ventricles
97
What causes the delay in the AV node?
the slow conduction rate in the AV node
98
What is the conduction rate of the AV node?
~.05 m/sec
99
Where does the action potential go from the AV node?
to the AV bundle, or the Bundle of His into the inter ventricular septum where it splits into a right and left bundle branch which then split into smaller branches called purkinjie fibers that reach into the walls of the ventricles
100
Which is faster, the AV bundle, branches, and purkinjie fibers or the cardiac muscle fibers?
AV bundle ect.
101
How fast is the AV bundle and branches conduction compared to the cardiac muscle fibers?
.3-.4 m/sec compared to 1-4 m/sec
102
the rapid conduction in the ventricles create a more coordinated contraction of the ventricle muscles, true or false?
True
103
What is the SA nodes intrinsic rate of generating action potentials?
60-80/minute
104
What is the AV noes intrinsic rate of generating action potentials?
~40/min
105
what is the AV bundle and purkinjie fibers intrinsic rate of generating action potentials?
~20/minute
106
What is an Ectopic focus?
When pacemaker cells grow in other places in the heart besides the nodes.
107
What is the Ectopic focus's effect on the heart
normally it isnt a big deal and van only make the heart beat a little bit slower or quicker and is usually masked by the faster action potentials of the SA node.
108
What happens if you have an ectopic focus and your SA node stops working?
This can become very dangerous and the ectopic focus can start controlling the heart rate. It is not modulated by the nervous system and can alter ECG readings causing misdiagnosis.
109
What is the key to contraction of cardiac muscle cells?
CALCIUM!
110
Where is calcium stored?
In the sarcoplasmic reticulum and in extracellular material
111
What can lead to heart arrhythmias?
small changes in blood calcium levels
112
What is the first channel to open when the action potential starts down the t-tubule?
calcium voltage gated channel responsible for the plateau phase of the action potential
113
what happens when the 1st calcium voltage gated channel in the t-tubule opens?
The Ca2+ diffuses into the cell and binds to calcium release channels on the membrane of the SR. also known as RyR channels
114
What are Ryanodine receptors (RyR)?
The calcium releasing channels found on the SR that extracellular calcium binds to allowing the calcium found in the SR to diffuse out of the cell and bind to troponin to initiate contraction.
115
What triggers the release of SR calcium?
Extracellular calcium, Calcium induced, calcium released
116
After the calcium unbinds from the troponin and the contraction is complete what happens to the calcium?
A Ca2+ ATPase pump on the SR pumps the calcium back into the SR stopping all contraction
117
What happens to the extracellular Ca2+ that is now in the cell after contraction is over?
a Na+--> Ca2+ exchanger (secondary active transport 3 Na+ to 1 Ca2+) moves the calcium from the cytoplasm back to the extracellular fluid.
118
what does the strength of the muscular contraction in the heart depend on?
The amount of Ca2+ that enters
119
How is the Na+ gradient in the t-tuble maintained since 3 na+ are being pumped in for every 1 Ca2+?
By the Na+/K+ ATPase
120
How do we record the electrical activity of the heart?
EKG
121
What does an EKG represent?
currents flowing through the extracellular fluids and the charges associated with the heart change.
122
what is the isoelectric point on an EKG?
when there is no deflection or no current and the EKG graph is flat
123
What does it mean if the EKG graph is flat?
it is at the isoelectric point and there is no deflection or current
124
How many leads are there in a typical EKG?
12
125
Diastole composes about --/3 of the cycle
2/3
126
Systole composes about --/3 of the cycle
1/3
127
If the pressure in the aorta is greater than the pressure in the left ventricle will the aortic semilunar valve be open or closed?
Closed
128
If the pressure in the Aorta is less than the pressure in the left ventricle will the aortic semilunar valve be open or closed?
Open
129
If the pressure in the left ventricle is greater than that in the left atria which valves will be closed?
The bicuspid/mitral valve
130
Is rapid inflow during Diastole or systole?
Diastole
131
What happens during rapid inflow? and what how long does it last?
It takes up approximately 1/3 of diastole.
| the mitral valve opens and the ventricle rapidly fills with blood passively
132
What does it mean when it says that blood is flowing passively during rapid inflow?
blood returning to the heart is merely running through the atrium and directly into the ventricle.
133
To what capacity do the ventricles fill during rapid inflow?
70-80%
134
Is diastasis part of systole or diastole?
Diastole
135
What happens during Diastasis, and how long does it last?
Takes up the 2nd 1/3 of diastole
| There is very little change in ventricular volume as the ventricles near capacity passive inflow of blood slows
136
Is Atrial systole part of systole or Diastole?
Diastole
137
What happens during Atrial Systole and when how long does it last?
Takes up the last 1/3 of diastole
| The atria contract which finished filling the last 20-30% of the ventricles with blood. (TOPPING OFF THE POP)
138
What percentage of the ventricular volume is filled during atrial systole?
20-30%
139
Is Atrial systole more important when we are at rest or when we are exerting ourselves?
Exerting ourselves
140
Is Isovolumetric contraction part of Systole or diastole?
Systole
141
What phase is at the beginning of systole
Isovolumetric Contraction
142
What happens during isovolumetric contraction?
When the pressure in the ventricle exceeds that of the atria the AV valve closes causing the 1st sound. The semilunar valve is also still closed because the ventricular pressure is less than the aortic pressure. PRESSURE INCREASES RAPIDLY BUT HTERE IS NO CHANGE IN VOLUME!
Phase is very brief and ends as soon as the ventricular pressure exceeds aortic pressure.
143
At about what pressure will the ventricular pressure exceed aortic pressure at the end of isovolumetric contraction?
~80mmHg
144
What constitutes the end of Isovolumetric contraction
The ventricular pressure overcoming that of the aortic pressure causing the Semilunar valve to open.
145
Is ejection part of diastole or systole?
Systole
146
What happens during ejection?
Once the semilunar valve is open, the blood is ejected from the ventricles to the aorta.
147
What is the maximum pressure reached during ejection?
approx. 120 mmHg
148
Is Isovolumetric relaxation part of systole or diastole?
diastole
149
What happens during Isovolumetric relaxation and when does it occur?
at the beginning of diastole the pressure drops rapidly and the ventricular pressure drops below aortic pressure closing the aortic valve which is the 2nd heart sound. Ventricular pressure is still greater than the atrial pressure so the bicuspid valve is also closed and the volume doesn't change! once the ventricular pressure drops below atrial pressure the bicuspid valve opens and the ventricles begin to fill again and start the cycle over.
150
What is responsible for the 2nd heart sound
closing of the semilunar valves
151
What is the cause of the dicrotic notch?
The sudden closing of the aortic valve produces a pressure wave as the blood pushes against it, resulting in the observed spike in aortic pressure.
152
What causes the 3rd sound?
The third sound is generated as blood rapidly flows into the ventricles causing the ventricular walls to vibrate.
153
What is the Stroke volume?
the difference between the end-diastolic volume and the end-systolic volume or the volume of blood pumped with each beat
154
What is the cardiac output?
the volume of blood that the heart pumps in one minute
155
What is the ejection fraction?
the percent of the end-diastolic volume that is pumped each beat.
156
If my EDV is 120ml and my stroke volume was 70 ml then what is my ejection Fraction?
(70/120x100)= 58%
157
An ejection volume above 55% is normal, True or False?
True
158
If you increase the end- Diastolic volume, the stroke volume--------
increases
159
If venous return increases, cardiac output ------
Increase
160
What is Starlings Law of the Heart?
The more the cardiac muscle is stretched during diastole the more forcefully it contracts
161
What is the degree of stretch at the end of diastole referred to as?
Preload
162
What is after load?
The force that opposes the flow of blood out of the ventricles during systole
163
When the aortic pressure exceeds 170mmHg the after load begins to reduce------ ------- and the workload on the heart greatly increases
cardiac output
164
is starlings law of the heart intrinsic or extrinsic?
Intrinsic
165
What are the primary players in the extrinsic regulation?
Autonomic nervous system and the endocrine system
166
acetylcholine slows the heart by---------- the membrane, thus moving the resting membrane potential further from threshold and flattening the slope of the pacemaker potential
Hyper-polarizing
167
Strong parasympathetic stimulation alone can decrease the heart rate by--- to---- %
10-20
168
What effect does parasympathetic stimulation have on the strength of contraction?
little to no effect
169
Sympathetic innervation in the auto rhythmic cells increases the heart rate by--------- the slope of the pacemaker cell, and ---------- the threshold for the voltage gated ------channels
increasing, lowering, Ca2++
170
Sympathetic stimulation of the contractile cells ----- the amount of calcium related from the SR, resulting in--------- strength of contraction, hence an --------- in stroke volume
increases, increased, Increase
171
Where is epinephrine and norepinephrine released from?
The adrenal medula
172
Is the effect of epinephrine and norepinephrine the same as the sympathetic or parasympathetic stimulation of the heart?
Sympathetic
173
How many minutes to brain cells last without oxygen before they die?
4-5 minutes
174
A concentration of <3.5 mM of potassium is considered
Hypokalemia
175
A concentration of >5 mM is considered
Hyperkalemia
176
Hyperkalemia results in-------- of the membrane potential
depolarization
177
Hypokalemia results in ------- of membranes
Hyperpolarization
