Question

Review & Practice She Exerci e in Motor wow m Muscle Physiology A Matching w ach on the left with red description on the rich A Resto of wiches ension changes more than length polarization C hating more motor units D. shift in transmembrane potential toward om E. contraction with no relaxation cycles 6. e contraction onse to single stimulus 7. depolarization G. length changes more than tension H. contraction with rapid relaxation cycles I. neurotransmitter time prior to tension K. reduction in contraction and performance L return of membrane to resting potential Luent period %. we summation r.incomplete setanus II. with 12. recruitment B. Descriptions Describe cach of the following types of muscle contraction 1. we summation 2. complete tetanus 3. twitch 4. incomplete tetanus

Answer 1

Ans1) Match the following

Isometric contraction	Tension changes more than length In this type of muscle contraction, the length of the muscle does not change but it leads to change in the tension of the muscle. The body is located in a static position and there is no range of motion during this contraction.
Complete tetanus	Contraction with no relaxation cycles In this the stimulus produced for the contraction of muscles are repeated and done so rapidly that there is no relaxation period or cycle. The relaxation phase is completely eliminated during the stimulation of muscle contraction
Repolarization	Return of membrane to resting potential This is the stage of action potential where the cell has a decrease in voltage due to the release of K+ ions along the electrochemical gradient and hence the membrane tends to return to its resting potential.
Acetylcholine	Neurotransmitter It is a type of neurotransmitter which helps in transmitting nerve impulse. It is released by the nerve cells and hence helps in sending signals to different types of cells.
Fatigue	Reduction in contraction and performance The fatigue is a stage when the muscles are no longer able to contract mostly due to accumulation of lactic acid and hence it reduces the overall muscle performance.
Isotonic contraction	Length changes more than tension In this type of contraction, the length of the muscles change and hence as it contracts, it tends to lengthen in its size.
Depolarization	Shift in transmembrane potential towards 0 mV The depolarization is a phase in action potential when the neuron sends the signal and hence in this the membrane potential become less negative due to the opening of the ion channels which leads to net positive ions to flow into the cell.
Latent period	Time prior to tension This is the time period before the start of the tension and is called the delay period. It is for around 2 milliseconds. It is the time period which is between the onset of stimulus and twitch onset
Wave summation	Fusion of twitches It is the combination of responsible which is created from motor unit resulting in production of two stimuli. It is the combination of two twitches where one twitch is equal to a single stimulus.
Incomplete tetanus	Contraction with rapid relaxation cycles This is the contraction where the muscles contraction and between every two contraction there is rapid phase of relaxation between the contraction cycle.
Twitch	Response to single stimulus It is the involuntary muscle fiber contraction of the fibers which constitute the muscle. It is a muscle contraction which is created by a single stimulus event
Recruitment	Activating more motor units When more motor units are activated and a single motor unit is a single unit of motor neurons and the muscles fibers around it. When there is recruitment of more motor units, it leads to additional contraction of muscles and enhances its strengthening.

Ans b)

1. Wave summation - It is the combination of responsible which is created from motor unit resulting in production of two stimuli. It is the combination of two twitches where one twitch is equal to a single stimulus.
2. Complete tetanus - In this the stimulus produced for the contraction of muscles are repeated and done so rapidly that there is no relaxation period or cycle. The relaxation phase is completely eliminated during the stimulation of muscle contraction
3. Twitch - It is the involuntary muscle fiber contraction of the fibers which constitute the muscle. It is a muscle contraction which is created by a single stimulus event
4. Incomplete tetanus - This is the contraction where the muscles contraction and between every two contraction there is rapid phase of relaxation between the contraction cycle.