Cardiac cell electropphysiology and excitation contraction coupling

The contractile cells of the atrium and ventricle are known as _______

Cardiomyocytes

SA and AV nodes are known as ________

pacemaker cells

in cardiomyocytes and purkinje cells what ion is used to initiate depolarization

Sodium

In the pacemaker cells what ion is used to initiate depolarization

calcium

besides the ion type what is the difference between cardiomyoctye and pace maker cells depolarization

pacemaker cell depolarization takes longer

list the 5 phases of action potential in the heart cells

0. depolarization

1. brief repolarization

2. plateau

3. repolarization

4. resting membrane potential

what phases of the action potential are unique to cardio myocytes and purkinje cells

• brief repolarization

• plateau

what ions enter and exit during the stages of an action potential in the cardio myocytes

0. Na in

1. K out

2. ca in

3. k out

4. return to resting membrane potential

in pacemaker cells what causes an automatic drift in RMP

the funny current

when you alter ion channels needed in creation of an action potential it can create _______

arrhythmias

the plateau in phase 2 of action potential is caused by an influx of ______

calcium

what are the types of calcium channels

• T type

• L type

• ligand gated

The T-type and L-type calcium channels are known as _______

voltage gated calcium channels

which of the voltage gated calcium channels activates first

T-type

what ligands stimulate the ligand gated calcium channel

• norepinephrine

• epinephrine

the ligand gated channel are opened by what type of receptors

beta receptors

what Ion is most important for repolarization

potassium

potassium channels determine the __________ and __________

• speed of repolarization

• effective refractory period

Increased vagal tone could do what in reference to potassium channels

• slows depolarization

• speeds repolarizatoin

with an active sympathetic nervous system will the depolarization take longer or shorter

shorter

in excitation-contraction coupling after the _____ type calcium channel opens and lets som calicum in the ______ receptor is stimulated and opens

• L

• ryanodine

the Ryanodine receptor is present on what organelle of the muscle cell

sarcoplasmic reticulum

after activating the ryanodine receptor with calcium what occurs

more calcium is released