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33 Cards in this Set
- Front
- Back
which side of the heart carries oxygenated blood and which side carries deoxygenated blood? |
right side --> deoxygenated left side --> oxygenated |
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what are the 2 nodes of the heart and where are they found? |
-SA node(sinoatrial node) --> found in posterior wall of RA near opening of superior vena cava -AV node (atrioventricular node) --> found in floor of right atrium near opening of coronary sinus
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draw a diagram showing the conducting system in the heart |
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what piece of equipment is required for measuring the resting potential across a cell membrane and how many of this particular piece of equipment is required |
a "needle electrode" is required 2 are needed 1 for inside the cell and one for outside the cell the needle electrode outside the cell is known as the "reference electrode" |
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what "resting potential" is seen inside the cell with respect to outside the cell |
-90mV |
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what pump maintains the concentrations of K+ and Na+ in the cell how many of each ion does it transfer and in what direction |
Na+/K+ ATP-ase pump
2Kin 3Na Out |
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the membrane is permeable to only one of Na+ and K+, which one of these is it permeable to |
• The membrane is permeable to K+ but not Na+ |
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pertaining to an ionic level, what happens in the cell to give the resting membrane potential of -90mV |
•The concentration gradient drives out K+ of the cell •The resulting electrical gradient pulls K+ in |
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what is the nernst equation |
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the electrical potential is determined by the relative concentrations of which ion on either side of the membrane? |
The electrical potential is determined by the concentrations of potassium ions (K+) on either side of the membrane (because it is selectively permeable to potassium) |
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to test the action potential of a cell, it can be stimulated, what are the 5 main phases of this which can be drawn on a graph of voltage against time |
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Na+ Ca2+ and K+ all travel across the cell membrane using ion channels, in what direction does each ion travel using these channels, and on what does the direction of flow in these ion channels depend? |
Na+ & Ca2+ inward currents K+ outward currents
• Ion currents may be inward or outward, depending on concentration gradient |
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how is the AP generated using ion channels? |
Voltage-gated, ion-selective channels open and close to generate the AP |
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what is the general common structure of cell membrane ion channels |
-they have 4 "phases" of protein groups (I-IV) -each phase has 6 sub-groups (S1-S6) -also present is a "P-loop" polypeptide chain
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what part of the channel do the P-loops form and what are they responsible for? |
“P-loops” form the narrowest part of the channel they are responsible for: -gating ion-flow -sensing voltage -filtering ion species |
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P-loops are responsible for channel activation and inactivation, what structural change do the P-loops undergo in order to achieve this |
• P-loops extend (or twist) for channel activation • P-loops retract (or twist) for channel inactivation |
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what are the 5 phases of the action potential? |
0- upstroke and overshoot 1- initial recovery 2- plateu 3- recovery 4- resting |
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during cell membrane action potential, in phase 0, upstroke and overshoot, what happens? |
• Na+ channels open, • Fast, inward Na+ current depolarizes the membrane (triggering closure of the channels) |
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during cell membrane action potential, in phase 1, initial recovery, what happens? |
• Na+ channels close |
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during cell membrane action potential, in phase 2, plateu, what happens? |
• Ca2+ channels open – slower, inward Ca++ current matches outward K+ and maintains the membrane near 0 mV |
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during cell membrane action potential, in phase 3, recovery, what happens? |
• K+ conduction increases and Ca++ decreases, repolarizing the membrane |
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during cell membrane action potential, in phase 4, resting, what happens? |
• Resting membrane potential determined by K+ channel conductance and concentration gradient • Na+– K+ pump helps maintain resting potential near -90 mV |
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what is the general structure of the contraction mechanism in cardiac muscle |
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what are the relative pressures in different places in the heart when certain valves close and can be used to show when they close |
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what generates the pressure in cardiac muscle? |
the contraction of the atria/valves |
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pressure drives blood flow through the heart in in what direction (in relation to pressure) |
from high to low pressure |
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what opens and closes the heart valves |
pressure |
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what is the pressure in the heart dependent on |
the peripheral resistance |
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what is the formula for Cardiac output and blood pressure/ total peripheral resistance (TPR) |
CO = HR x SV TPR = CO x PVR (peripheral vascular resistance) |
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as aortic pressure increases what happens to coronary flow? |
it also increases... they're pretty proportional |
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when is the window for coronary flow form the aorta back through the coronary arteries |
during the diastole |
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where would you listen to hear the different valve sounds? |
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what is aortic stenosis |
the narrowing of the aortic valve |