The Force-Frequency Relation in the Heart (The Relation Between Frequency

question 8

Multiple Choice

The force-frequency relation in the heart (the relation between frequency of stimulation and strength of the heart) is caused principally by

• A) Stretch of the cardiac muscle with Increasing frequency of stimulation
• B) Increased in the sensit ivity of the myofilaments to Ca₂+
• C) Phosphorylation of TnC
• D) Increased [Ca₂+] in the mitochondria
• E) Increased [Ca₂+] transients due to loading of the SR

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Definitions:

Maltose

A disaccharide sugar produced from the enzymatic breakdown of starch that consists of two glucose units.

Substrate

The surface or material on or in which an organism, enzyme, or cell lives or acts, often referring to the substance upon which an enzyme acts.

Chemical Reaction

A process that involves rearrangement of the molecular or ionic structure of a substance, as opposed to a change in physical form or a nuclear reaction.

Benedict's Solution

A chemical reagent used to test for the presence of reducing sugars.