Defintions Twitch, Tetanus, Motor Unit, Recruitment, Isotonic, Isometric, Concentric Eccentric Contractions Flashcards
What is a twitch in muscle physiology?
A twitch is a single contraction and relaxation of a muscle fiber in response to a single stimulus.
True or False: Tetanus is characterized by a sustained contraction without relaxation.
True
Define a motor unit.
A motor unit consists of a motor neuron and all the muscle fibers it innervates.
What is recruitment in the context of muscle contraction?
Recruitment refers to the process of activating additional motor units to increase muscle force.
Fill in the blank: Isotonic contraction occurs when a muscle changes _____ while maintaining a constant tension.
length
What are the two types of isotonic contractions?
Concentric and eccentric contractions.
Which type of contraction shortens the muscle while generating force?
Concentric contraction.
True or False: Eccentric contractions occur when a muscle lengthens under tension.
True
What is the main difference between isotonic and isometric contractions?
Isotonic contractions involve a change in muscle length, while isometric contractions involve no change in muscle length.
What is the role of motor units in muscle contraction?
Motor units are responsible for transmitting signals from the nervous system to initiate muscle contractions.
How does the frequency of stimulation affect muscle contraction?
Increased frequency can lead to summation and possibly tetanus, resulting in stronger muscle contractions.
Define the term ‘summation’ in muscle physiology.
Summation is the process where successive stimuli increase the strength of muscle contractions.
What is a key characteristic of a tetanic contraction?
A tetanic contraction is sustained and does not allow for relaxation between stimuli.
Fill in the blank: During _____ contraction, the muscle generates force while lengthening.
eccentric
What is the physiological significance of muscle recruitment?
Recruitment allows the body to adjust the force of muscle contractions based on the demands of the activity.
Which type of contraction is primarily used during activities like lifting weights?
Concentric contraction.
True or False: Isometric contractions can contribute to muscle strength without changing muscle length.
True
What happens during a concentric contraction?
The muscle shortens while contracting against resistance.
Define the term ‘isometric contraction’.
An isometric contraction is a type of muscle contraction where the muscle length remains the same while generating force.
What is the effect of muscle fatigue on twitch and tetanic contractions?
Muscle fatigue can reduce the strength and duration of both twitch and tetanic contractions.
Fill in the blank: The process of activating more motor units to increase muscle force is called _____ .
recruitment
What is the relationship between muscle fiber type and contraction type?
Different muscle fiber types (slow-twitch vs fast-twitch) influence the type of contractions they are best suited for.
True or False: An increase in muscle length during an isotonic contraction requires a decrease in tension.
False
What type of contraction is most effective for controlling the descent of a heavy load?
Eccentric contraction.
