A&P MIDTERM: Contraction of Whole Muscle

In the next lab stimulation, what was: A) threshold stimulus B) voltage when recruitment was obvious C) voltage when all motor units were recruited

A) .3V B) .4V C) 1.5V

Identify the three phases of a muscle twitch from the following definitions: A. Sarcomeres shorten _____________________ B. Sarcomeres return to a resting length _______________________ C. Sarcomeres at resting length ___________________________

A. Contraction B. Relaxation C. Latent

A. Temporal summation results from: B: in temporal summation, you must _______ (increase or decrease) the time interval between stimuli

A: stimulating the muscle rapidly so that one contraction is not finished when another begins B: decrease

Which of the following contract in all or none fashion? A. Whole muscle B. Single muscle fiber

B. Single muscle fiber

Below is a list of five phases of temporal summation. Put in the correct order and describe each stage A) Fatigue B) Incomplete tetanus C) Treppe D) complete tetanus

1. Treppe - when a muscle is stimulated frequentyly. Each muscle twitch shows an increase in strength and then complete relaxation 2. Incomplete Tetanus - rapid & shortened contraction/relaxation cycles where some degree of relaxation is visible. This results from increased frequency of stimulation 3. Complete Tetanus - rapid muscle stimulation causes the contraction/relaxation cycles to fuse into a total contraction, with no relaxation 4. Fatigue - the muscle can no longer hold its level of tension and gradually elongates evem though adequate stimulation continues. It is a result of a build up of lactic acid & lack of ATP

In the motor unit summation section, how many motor units were required to lift the weight when: A. The wright was 160 B. The weight was 80

A) many B) few

A) in the length-tension relationship experiment, at what degree of stretch was the maximum tension developed? B) what would congestive heart failure be an example of?

A)Moderately stretched B) overstretched muscle

The development of tension in a muscle, in response to a stimulus above threshold, is called a ______________________

Contraction