Muscular System Functions Quiz & Flashcards

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Questions and Answers

Why are multiple tissue types necessary in a whole skeletal muscle?

To conduct electrical signals efficiently

To allow for flexibility in movement

To provide structural support only

To enable the muscle to contract and relax effectively (correct)

What is the role of acetylcholine (ACh) in muscle cell function?

Facilitates the breakdown of fats for energy

Triggers muscle contraction by stimulating receptors on the muscle cell membrane (correct)

Regulates the heart rate

Inhibits nerve transmission

How is endurance exercise different from resistance exercise in their effects on muscle tissue?

Resistance exercises primarily target slow twitch muscle fibers

Resistance exercises enhance cardiovascular endurance

Endurance exercises lead to muscular hypertrophy

Endurance exercises promote increased oxygen utilization in muscles (correct)

What is the importance of resting membrane potential (RMP) in muscle cell function?

Allows for generation of action potentials to initiate muscle contractions Signup and view all the answers

Why are small and large motor units different in form and function?

Small motor units produce more force but less precise movements than large motor units Signup and view all the answers

What distinguishes slow twitch fibers from fast twitch fibers?

Fast twitch fibers are rich in myoglobin and mitochondria compared to slow twitch fibers Signup and view all the answers

During long-duration exercise, what leads to fatigue?

Build-up of lactic acid in muscles Signup and view all the answers

Which molecules are crucial for the process of excitation-contraction coupling in muscle cells?

Calcium and troponin Signup and view all the answers

What is the primary difference between small and large motor units?

Large motor units are responsible for fine motor control while small motor units are for gross motor control. Signup and view all the answers

What is the main role of acetylcholine (ACh) in muscle cell function?

Stimulating muscle contraction by depolarizing the muscle cell membrane Signup and view all the answers

Which of the following is a key characteristic of slow twitch muscle fibers?

They have a high resistance to fatigue and are rich in mitochondria Signup and view all the answers

Why is the resting membrane potential (RMP) crucial for muscle cell function?

It maintains the electrical gradient needed for proper muscle cell excitability. Signup and view all the answers

What defines the mechanism that supplies a muscle with ATP based on exercise duration?

The balance between aerobic and anaerobic energy production pathways Signup and view all the answers

How do endurance and resistance exercises differ in their effects on muscle tissue?

Endurance exercises lead to increased mitochondrial density, while resistance exercises promote hypertrophy by increasing myofibril size. Signup and view all the answers

Study Notes

Multiple Tissue Types in Skeletal Muscle

Skeletal muscle comprises multiple tissue types, including muscle fibers, connective tissue, blood vessels, and nerves.
Each tissue contributes to the overall function of the muscle, allowing contraction, support, and nutrient delivery.

Role of Acetylcholine

Acetylcholine (ACh) is a neurotransmitter vital for muscle contraction.
ACh is released at the neuromuscular junction, triggering depolarization of the muscle cell membrane.

Endurance Exercise vs. Resistance Exercise

Endurance exercise primarily affects slow-twitch muscle fibers, increasing their oxidative capacity.
Resistance exercise focuses on fast-twitch muscle fibers, increasing their size and strength.

Resting Membrane Potential (RMP)

RMP in muscle cells is essential for maintaining excitability.
A stable RMP allows for rapid depolarization in response to nerve impulses, initiating muscle contraction.

Small vs. Large Motor Units

Small motor units consist of a single motor neuron and a small number of muscle fibers.
Large motor units have a single motor neuron innervating a large number of muscle fibers.
Small motor units are recruited for fine motor control, while large motor units are used for powerful movements.

Slow Twitch vs. Fast Twitch Fibers

Slow twitch fibers are specialized for endurance activities, with high oxidative capacity and slower contraction speeds.
Fast twitch fibers are designed for power and speed, containing fewer mitochondria and producing rapid, forceful contractions.

Fatigue During Long-Duration Exercise

Long-duration exercise leads to fatigue due to various factors.
These include depletion of glycogen stores, accumulation of lactic acid, and disruptions in calcium regulation.

Molecules in Excitation-Contraction Coupling

Acetylcholine (ACh) initiates the process by binding to receptors on the muscle cell membrane.
Calcium ions (Ca2+) are crucial for muscle contraction, released from the sarcoplasmic reticulum.
Troponin and tropomyosin act as regulatory proteins, controlling the interaction of myosin and actin filaments.

Difference Between Small and Large Motor Units

The primary distinction is the number of muscle fibers each motor unit controls.
Small motor units regulate fine movements, while large motor units are responsible for generating larger forces.

Role of Acetylcholine in Muscle Contraction

Acetylcholine acts as a neurotransmitter, triggering depolarization of the muscle cell membrane.
This depolarization initiates a cascade of events leading to muscle contraction.

Slow Twitch Fiber Characteristics

High oxidative capacity: Slow twitch fibers are rich in mitochondria, enabling them to generate ATP efficiently using oxygen.
Slow contraction speed: They contract more slowly than fast twitch fibers.
Fatigue resistance: These fibers are resistant to fatigue due to their high oxidative capacity.

Importance of Resting Membrane Potential

The RMP is essential for maintaining muscle cell excitability.
A stable RMP allows for rapid depolarization in response to nerve impulses, triggering muscle contraction.

ATP Supply in Muscle Cells

Phosphagen system: provides immediate energy for short bursts of activity (0-10 seconds).
Glycolytic system: generates ATP for moderately intense exercise (10-90 seconds).
Oxidative system: sustains long-duration exercise (over 90 seconds) by using oxygen to produce ATP.

Effects of Endurance and Resistance Exercises

Endurance exercise increases the number of mitochondria and blood vessels in slow twitch fibers, enhancing their oxidative capacity.
Resistance exercise primarily targets fast twitch fibers, promoting hypertrophy (muscle growth) and increasing strength.

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Test your knowledge on the role of the muscular system in whole body homeostasis, tissue types present in a skeletal muscle, parts of a skeletal muscle fiber and their functions, and the steps of excitation, excitation-contraction coupling, and relaxation in muscle cells.

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