Muscle Contraction Types and Functions Quiz

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What type of contraction is isotonic contraction?

The length of the muscle changes (correct)

The muscle does external work

The duration is adapted to muscle functions

The tension remains constant

What factor determines muscle tension in a single muscle fiber?

Length of the tendons

Thickness of the epimysium

Frequency of action potential (correct)

Amount of myoglobin

What muscle provides slow contraction for continual, long-term support against gravity?

Gastrocnemius

Rectus femoris

Biceps brachii

Soleus (correct)

Which factor results in lesser tension developed in a single muscle fiber?

Greater rate of fatigue Signup and view all the answers

What must ocular movements be in order to maintain fixation of the eyes on specific objects?

Extremely rapid Signup and view all the answers

What muscle contract moderately rapidly to provide sufficient velocity of limb movement for running and jumping?

Gastrocnemius Signup and view all the answers

What are factors determining muscle tension in a single muscle fiber?

Rate of fatigue and frequency of action potential Signup and view all the answers

In which type of contraction does the duration adapt to the functions of respective muscles?

Isotonic contraction. Signup and view all the answers

What is a motor unit composed of?

A motor neuron and a group of skeletal muscle fibers Signup and view all the answers

Which type of muscles generally have more nerve fibers for fewer muscle fibers in a motor unit?

Small muscles that react rapidly and require fine control Signup and view all the answers

Which muscle fiber type can deliver greater amounts of powerful forces for a few seconds to a minute or so?

Fast-twitch fibers Signup and view all the answers

Which muscle fiber type provides endurance and delivers prolonged strength of contraction over many minutes to hours?

Slow-twitch fibers Signup and view all the answers

What are fast-twitch muscle fibers mainly composed of?

Fast-twitch fibers Signup and view all the answers

Which feature characterizes slow-twitch muscle fibers?

Prolonged strength of contraction over hours Signup and view all the answers

Why do small muscles that require fine control have more nerve fibers for fewer muscle fibers?

To allow for precise and coordinated movements Signup and view all the answers

What is a characteristic of slow fibers compared to fast fibers?

Smaller nerve fibers innervate them Signup and view all the answers

What gives slow muscles a reddish appearance?

Myoglobin Signup and view all the answers

Which fiber type has greatly increased numbers of mitochondria?

Slow fibers Signup and view all the answers

What is the primary function of myoglobin in slow fibers?

Store oxygen until needed Signup and view all the answers

Which fiber type has a large amount of glycolytic enzymes for rapid energy release?

Fast fibers Signup and view all the answers

What contributes to the reddish appearance of slow muscles?

Myoglobin Signup and view all the answers

Which fiber type is characterized by having a less extensive blood supply compared to slow fibers?

Fast fibers Signup and view all the answers

What is the primary function of myoglobin in slow muscles?

Store oxygen until needed Signup and view all the answers

What does summation in muscle contraction refer to?

Adding together individual twitch contractions to increase the intensity of muscle contraction Signup and view all the answers

Which of the following is NOT a way in which summation can occur in muscles?

By decreasing the overlap between actin and myosin filaments Signup and view all the answers

What is the term used to describe the process of successive contractions fusing together into a smooth and continuous muscle contraction?

Tetanization Signup and view all the answers

Which factor contributes to tetanus in muscle contractions?

High calcium ion concentration in the sarcoplasm Signup and view all the answers

What happens during tetanic contraction?

Release of calcium from sarcoplasmic reticulum is faster than the previous action potential is pumped back Signup and view all the answers

What is one cause of muscle fatigue?

Rapid build-up of lactic acid Signup and view all the answers

In multiple fiber summation, what happens as the strength of the stimulus increases?

Smaller motor units are stimulated more Signup and view all the answers

What is the main difference between fast-twitch fibers and slow-twitch fibers?

Fast-twitch fibers are large in diameter, slow-twitch fibers are small in diameter Signup and view all the answers

Which property of skeletal muscles is associated with the 'all or none law'?

Excitability Signup and view all the answers

What does the 'all or none law' state about muscle contraction?

All muscle fibers within a motor unit contract maximally in response to a stimulus Signup and view all the answers

Which type of stimulus is required to elicit an action potential in skeletal muscles?

Threshold stimulus Signup and view all the answers

What happens during depolarization of an action potential in skeletal muscles?

Na+ influx occurs Signup and view all the answers

Which type of contraction involves muscle length remaining constant but tension changing?

Isometric contraction Signup and view all the answers

What defines tetanus in the context of muscle contraction?

'All or none law' being obeyed during contraction Signup and view all the answers