CV 3 Myocytes And EP Flashcards
What is pattern of depolarization in heart
SA to AV through atria
To bundle of his
To right and left bundle
To purkinje
All different areas of cardiac depolarization what
Look more or less alike
P
Q
R
T
Atrial depolarization
Depolarization down branch bundles of septum
Ventricular depolarization
Ventricular repolarization
Way ventricle depolarizes
Way septum depolarizes
Apex to base
Base to apex
Ventricle phases 4 0 1 2 3 4
4- resting membrane potential, recovery
0- quick upstroke, na in rapidly
2- calcium in during plateau
3- k flows out, repolarization
What happens to potassium gate when cell depolarizes
Closes. Open at rest. Not leak channels
K channels open when what
Myocyte repolarizes
Not leak channel
SA node action potential sequence
4 Na leaks in
0 Slowly depolarizes in phase 0 (funny current)
Upstroke is influx of calcium once over threshold f
3 K out
Speed of signal going through av node to bundles and why
Sloe because fibrous tissue separates atria from ventricles
How sa node and ventriclular action potential charts differ
In SA node no 1 and 2, no plateau, just depolarization and repolarization
What happens at -60 mv in sa node
Na in faster than k leaving
What happens in funny current
Na in slowly depolarizing cell
How funny channels are opened
When voltage drops below threshold
How all other channels than funny are opened
Voltage above threshold
How to change heart rate through funny current
More funny current, depolarize quicker, steeper curve
Slow l type and transitory calcium channels result in what
Calcium channel open, comes in cell, depolarization rapid but not as fast as sodium
What forms a dyad
Sarcoplasmic reticulum and t tubule
What holds myocytes together
Macula adherens
Funny current only works where
SA node
Which channel responsible for phase 0
Which responsible for calcium moving in
Fast sodium channel
Slow L type calcium channel
What is the subunit of the slow l type calcium channel that opens ___ receptors which contribute to contraction
DHP, ryanodine
DHP receptor inhibited by what and upregulated by what
Diltiazem
Adrenergics
Ryanodine located where
Gated by what
Contributes to what
SR
Ca
Contraction
NCX Exchanger
Where
What ions
Gating
Contributes to what phase
Sarcolemma, t tubule
1 Ca 3 Na
Always open
To phase 1 dip, relaxation
SL Ca ATPase Where When open What ion Contributes to what
Sarcolemma
Ca, always open using ATP
Minor contribution to relaxation
SERCA/SR Ca ATPase
Where
Ion
When open
What contribution
SR
Ca
Always, ATP
Biggest contribution to relaxation
Fast na channels
Where they are
What ion
Gating
Contributes to what
T tubule
Na
Voltage
Phase 0
K1 inward rectifier
Where
What ion
Gating
Contributes to what
Sarcolemma
K
Closes with voltage
Phase 4, closes with depolarization
K to transient outward
Where
When open
Contributes to what
Sarcolemma
Opens with voltage
Contributes to phase 1 dip, closes quickly
Kr rapid delayed K Where What ion Gating Resp for what
Sarcolemma
K
Opens with voltage
Repolarization in phase 3, opens slowly
Ks slow delayed K Where Ion Gating Resp for what
Sarcolemma
K
Opens with voltage
Repolarization in phase 3, opens slower than Kr
Na K ATPase Where What ions Gating Contributes to what
Sarcolemma
3 na 2 k
Always open using ATP
Na K ATPase, inhibited by digoxin
Phases controlled by what 0 1 2 3 4
Fast sodium
Potassium
Calcium in, K out
Repolarization, K out
K channels open (not leak), hyperpolarized
What cause contraction while pumping ca out
Delay
What you have to do to close ryanodine receptor
Pump all of calcium out
K1 inward rectifier closes when
Cell depolarizes
``what goal of transient channel is
Keeping contraction from being too long, makes plateau shorter
Phase 3 which channels
Slow delayed potassium channels
Inward rectifier closes when
Slightly above nernst potential for K, 30 mv
Nernst equation for sodium calcium exchanger
61 x log (na out/na in)^3 x (ca in / ca out) mv
In phase 4 what is na ca exchanger doing
Shoving ca out
What is exchanger doing at -7.2 phase 2
Pull positive into cell 3 na in 1 ca out
How digoxin works and effects sodium calcium exchanger
Inhibits sodium potassium pump= na in cell is higher. More negative rmp. Spend more time bringing calcium in, sodium concentration higher
What does isoproterenol b adrenergic agonist do
Up regulate l type ca exchanger, more ca in and stronger contraction
What happens when taking diltiazem
Blocks ventricular ca channel, weaker contraction
What ca channel blocker does on
L type smooth muscle
Heart
Dilation, increase co from less resistance, BP lowers, feel weak
Ca influx to sa node decreases, decrease heart rate. Less force of contraction because less ca in ventricle. Heart rests
Lead I
Between arms
Lead two
Arm to opposite leg
Lead 3
Arm to same side leg
Where we get maximum r wave
Avf
R wave biggest in 1, 2, or 3
Lead 2, looks right arm to left leg
What is q wave on ekg
Septal depolarization
