Topic 7 Muscular System: Types of Muscle Response

Question 1

• Response of a single muscle fiber to brief stimulus; the steps are the latent period, contraction, and relaxation

Answer 1

1. Simple Twitch

Question 2

a. Latent Period
b. Contraction
c. Relaxation (absolute refractory period)

Answer 2

Types of Simple Twitch

Question 3

• Time between stimulation and onset of contraction; lag

- An action potential spreads on the sarcolemma and Ca2+ ions are released

Answer 3

a. Latent Period

Question 4

• Contracts following sliding filament model as on previous page

Answer 4

b. Contraction

Question 5

• Time where the muscle is unresponsive to a stimulus

Answer 5

c. Relaxation (absolute refractory period)

Question 6

Second type of muscle

Answer 6

Summation and Tetanus

Question 7

• Contractions combine and become stronger and more prolonged (repeated action potentials summate)

Answer 7

Summation

Question 8

• Continuous sustained contraction where a muscle cannot relax and will release if maintained
• In tetanus, the rate of muscle stimulation is so fast that twitched blend together into one smooth constant

Answer 8

Tetanus

Question 9

• State of partial contraction where the muscle is never completely relaxed

Answer 9

Tonus

Question 10

1. Sub-threshold stimuli: no motor units respond
2. Threshold: one motor unit responds
3. Sub-maximal: increasing number of motor units respond
4. Maximal: all motor units respond
5. Supra-maximal: all motor units respond

Answer 10

Types of stimuli that can stimulate these responses

Question 11

• Speed and amplitude remain constant during an action potential. As stimulus intensity increases, the number of action potentials increases

Answer 11

Note