Muscle Physiology Quiz

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Questions and Answers

What is the role of the agonist muscle during movement?

It stretches the antagonist muscle.

It contracts to initiate the movement. (correct)

It can also relax during the same movement.

It remains inactive during the contraction.

How do motor units contribute to the production of maximum muscle force?

Fewer motor units are required in high-intensity resistance training.

They contract randomly to produce maximum force.

All motor units must reach their specific threshold to be activated. (correct)

Only a few motor units are activated at a time.

What happens when a weak nerve impulse is transmitted to motor units?

It causes no contraction at all.

All motor units are activated immediately.

Only those motor units with low thresholds are activated. (correct)

The entire muscle completely contracts.

Which statement best describes antagonist muscles?

They oppose the movement initiated by the agonist. (D) Signup and view all the answers

What principle determines that a muscle fiber will contract fully or not at all?

The all-or-none principle. (B) Signup and view all the answers

What feature of long muscle fibers primarily contributes to their functionality?

They have a greater range of movement. (A) Signup and view all the answers

Which type of motor unit is essential for fine motor control, such as that needed for eye movements?

Small motor units (B) Signup and view all the answers

What is the primary function of the motor nerve in the neuromuscular system?

To control muscle movement. (D) Signup and view all the answers

Which component of the motor unit receives the motor impulse?

Dendrite (B) Signup and view all the answers

What happens at the motor end plate during muscle contraction?

Chemical reactions occur at the neuromuscular junction. (B) Signup and view all the answers

What distinguishes a large motor unit from a small motor unit?

It stimulates a greater number of muscle fibers. (B) Signup and view all the answers

Which part of the neuron transmits the impulse towards the muscle fibers?

Axon (D) Signup and view all the answers

What characterizes muscle fibers within a specific motor unit?

They always belong to the same fiber type. (A) Signup and view all the answers

What is the primary characteristic of cardiac muscles?

Fatigue resistant (D) Signup and view all the answers

How do smooth muscles contribute to the function of the body's internal organs?

Provide uniform and slow contractions (B) Signup and view all the answers

Which system primarily controls the action of muscles?

Nervous system (B) Signup and view all the answers

What percentage of body mass does skeletal muscle typically comprise in men?

42-47% (B) Signup and view all the answers

Which of the following best describes the role of the muscular system in relation to the skeletal system?

It generates body movement. (D) Signup and view all the answers

Which of the following statements regarding muscle fatigue is true?

Fatigue-resistant muscles can sustain prolonged activity. (B) Signup and view all the answers

What is the primary function of the circulatory system in relation to the muscular system?

Supplies muscles with oxygen and nutrients. (A) Signup and view all the answers

Which type of muscle is responsible for involuntary movements within internal organs?

Smooth muscle (B) Signup and view all the answers

Study Notes

Muscle Fibre Types

Short, dense muscle fibres allow for precise movements.
Long, dense muscle fibres allow for a greater range of movement.
Bulkier muscles contain more fibres packed together.

Neuromuscular System

Links the nervous system and muscular system.
Motor nerves carry impulses from the brain to muscle fibres, enabling muscle movement.

Motor Unit

Consists of a motor nerve and the muscle fibres it stimulates.
Small motor units activate a few muscle fibres and are important for fine motor control.
Large motor units activate more muscle fibres and are involved in gross movement.
All muscle fibres within a motor unit are of the same type.

Motor Neuron

Has an axon and a dendrite.
Dendrites receive impulses and transmit them to the axon.
Axons branch out at the motor end plate, connecting to muscle fibres.

Motor End Plate

The neuromuscular junction where nerve impulses are transmitted to muscle fibres.
Chemical reactions occur at this junction, causing muscle fibre contraction.
Muscle twitch is a single contraction caused by a motor unit activation.

All-or-None Principle

Motor units contract completely or not at all.
Maximum muscle force requires all motor units in a muscle group to be activated.
Threshold of activation must be reached for each motor unit to contract.
Increasing resistance requires stronger impulses to activate more motor units.

Muscle Contractions

Skeletal muscles work in opposing pairs.
Agonist muscles initiate movement while antagonist muscles oppose movement.
Agonist muscles contract, while antagonist muscles relax during movement.

Function of Muscular System

Over 600 muscles in the body, each with a specific function.
The nervous system controls muscle action.
The circulatory system provides blood supply for muscle function.

Roles of Muscular System

Works with the skeletal system to generate body movement.
Contributes to strength, endurance, and speed.
The heart muscle pumps blood throughout the body.
Chest muscles assist with breathing.
Muscles in the digestive system move food through the tract.

Types of Muscle Tissue

3 types: cardiac, smooth, and skeletal.
Makes up 30-35% of body mass in women and 42-47% in men.

Cardiac Muscle

Combines characteristics of skeletal and smooth muscle.
Responsible for the heart's contraction and blood pumping.
Highly resistant to fatigue.
Involuntary activation by the autonomic nervous system.
Striated (striped) muscle fibres.
Cardiac muscles are responsible for heart contraction.
Smooth muscles control involuntary actions in organs and blood vessels.
Skeletal muscles allow for voluntary movement and control.

Smooth Muscle

Found around internal organs: blood vessels, respiratory tract, iris, gastrointestinal tract.
Slow, uniform contractions.
Adjusts organ function to meet bodily demands.
Fatigue-resistant.
Involuntary activation.
Spindle-shaped fibers arranged in sheets.

Skeletal Muscle

Attached to bones for voluntary movement.
Fast, powerful, and often fatigue quickly.
Striated (striped) appearance.
Responsible for body movement and posture.

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Description

Test your knowledge on muscle fibre types, the neuromuscular system, and motor units. This quiz covers the essential functions of motor neurons and the connections between the nervous and muscular systems. Perfect for students studying human physiology and anatomy.