Ca Channels in the Heart

[lemonade90]

In FA 2012 pg 286, ventricular tissue is shown as having Ca coming into the cell from the outside during an action potential Phase 2 while in the musculoskeletal chapter pg 412, the heart is shown NOT to have Ca induced Ca release from the sarcoplasmic reticulum.

Whats up with that?

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[Morsetlis]

Heart has CICR. That's why a Ringer's solution is needed to make hearts beat in vitro experimentally.

CICR is also used in glial cells (astrocytes / synaptic plasticity) and other random crap.

CICR is not needed under normal physiological condition for skeletal muscles because the DHP-R is voltage-gated and linked physically to the RyR on the SR. However, in malignant hyperthermia or caffeine contractures, CICR may play a role in skeletal muscle.

http://physrev.physiology.org/content/89/4/1153.long

 

[lemonade90]

Thanks. Lol. I misread the diagram for some reason. The MSK diagram doesn't involve the heart at all. The diagram on the following page does.

Perhaps my ratio of sleep to study time is not optimal.