Lecture 15 LO12 (Super awesome mega happy lecture, gee i sure hope i go to the good day facotry *good day facotry behind him*)

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What is temporal summation in skeletal muscle?

Increased tension when another stimulus arrives before the muscle has completely relaxed.

Why can a second stimulus produce more tension before the first twitch ends?

Additional Ca²⁺ release increases cross-bridge activation while tension from the first twitch remains.

What happens when successive stimuli are far enough apart for complete muscle relaxation?

They produce separate twitches without temporal summation.

How does increasing stimulation frequency generally affect muscle tension?

It promotes summation and can produce greater, more sustained tension.

What is incomplete, or unfused, tetanus?

Sustained tension with partial relaxation between repeated contractions.

What does incomplete tetanus look like on a myogram?

Elevated tension with repeated rises and falls.

What is complete, or fused, tetanus?

Sustained tension with partial relaxation between repeated contractions.

What does complete tetanus look like on a myogram?

Elevated tension with repeated rises and falls.

How does stimulation frequency differ between incomplete and complete tetanus?

Smooth, sustained tension with no noticeable relaxation between contractions.

Why does frequent stimulation prevent complete relaxation between muscle contractions?

Ca²⁺ remains sufficiently available to maintain cross-bridge activation between stimuli.

Does temporal summation mean individual muscle action potentials become larger?

No. Mechanical tension sums because repeated action potentials maintain greater Ca²⁺ availability.

How does recruitment differ from temporal summation?

Recruitment activates more motor units; temporal summation increases force