Removal of External Ca²⁺ to Levels Below About 0

question 1

Multiple Choice

Removal of external Ca²⁺ to levels below about 0.2 mM result in no discernible force from the heart. This is because

• A) There is no cardiac action potential without extracellular Ca²⁺
• B) There is no calcium-induced-calcium release without extracellular Ca²⁺
• C) Ca²⁺ cannot enter over the NCX to activate the myofilaments
• D) Ca²⁺ is pumped out of the cell by the PMCA
• E) TnC is insensitive to Ca²⁺ when the heart is relaxed

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Definitions:

Extraversion

A personality trait characterized by energy gain from external social interactions and activities, opposite of introversion.

Outgoing

Characterized by an extroverted, socially confident, and friendly behavior.

Assertive

Referring to the quality of being self-assured and confident without being aggressive, enabling clear and respectful communication of one's needs and desires.

Extraverted

Exhibiting an outgoing, socially confident personality and engaging with the external world.