The Physiology of Muscle Contraction - WAVE SUMMATION and TETANUS

Question 1

What is the Summation of contractions?

Answer 1

It means that two or more contractions can be added together or overlapped.

Question 2

How is Summation produced?

Answer 2

When a second action potential arrives before a contraction can completely relax. When
this happens, this second action potential will cause a
second contraction which is more powerful than the first.

Question 3

*Occurs in many
muscles to produce
smooth, continuous
movements

Answer 3

WAVE SUMMATION and TETANUS

Question 4

Wave summation eventually causes ______ ________a sustained, quivering contraction.

Answer 4

incomplete tetanus

Question 5

If many contractions are summated, they will fuse together into a single, long, powerful contraction called _________ ____________.

Answer 5

complete tetanus.

Question 6

In real life, complete tetanus is very rare b’c the
maximum firing of nerves is usually _____ shocks/second. However, using ‘super-human’
strength (as with lifting a car off of someone) could be an
example.

Answer 6

40-50

Question 7

What can summation lead to?

Answer 7

Tetanus

Question 8

40-50 shocks per second

Answer 8

Complete tetnus

Question 9

If action potentials arrive in quick succession, the

sarcoplasmic reticulum doesn’t have time to pump the Ca+ back inside between each action potential. What happens?

Answer 9

The result: a large Ca+ concentration that lengthens the contraction.

Question 10

What must be returned to the sarcoplasmic

reticulum to stop a contraction—so that the myosin heads can detach from the actin filaments.)?

Answer 10

calcium

Question 11

Has a high frequency stimulus and is very rare

Answer 11

Complete tetnus