Muscular System Overview: Parts 1 & 2

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Questions and Answers

What is the primary characteristic of smooth muscle fibers?

Striated appearance

Multinucleated

Cylindrical with pointed ends (correct)

Branched structure

Which type of muscle tissue is responsible for voluntary movements?

Skeletal muscle (correct)

Smooth muscle

Cardiac muscle

All muscle types

How does cardiac muscle contraction differ from skeletal muscle contraction?

Cardiac muscle is under voluntary control

Cardiac muscle contraction occurs rhythmically and without nervous stimulation (correct)

Cardiac muscle does not relax between contractions

Cardiac muscle fibers are multinucleated

What is a key function of skeletal muscles?

Supporting body posture against gravity Signup and view all the answers

Which structural characteristic is not associated with skeletal muscle fibers?

Uninucleated cells Signup and view all the answers

What is the function of smooth muscle tissue?

Controlling involuntary contractions in internal organs Signup and view all the answers

What occurs at the neuromuscular junction to initiate muscle contraction?

Electrical impulses are converted to chemical signals Signup and view all the answers

What is released when ATP breaks down during muscle contraction?

Heat Signup and view all the answers

What does fascia do in the skeletal muscular system?

Connects muscle to bone Signup and view all the answers

In the context of skeletal muscles, what is the origin of a muscle?

The attachment site to the stationary bone Signup and view all the answers

Which of the following best describes agonist muscles?

They are responsible for the majority of a movement Signup and view all the answers

What role do bursae play within the muscular system?

They provide cushioning and lubrication Signup and view all the answers

Which muscle pair acts as antagonists in arm movement?

Biceps and triceps Signup and view all the answers

What type of muscle fibers are found within a fascicle?

Skeletal muscle fibers Signup and view all the answers

What is the primary function of skeletal muscles in relation to internal organs?

Protecting internal organs Signup and view all the answers

What is located between tendons and bones to facilitate movement?

Bursae Signup and view all the answers

What is the role of the agonist muscle during contraction?

It contracts to facilitate movement. Signup and view all the answers

Which cellular component of a muscle fiber serves as a calcium storage site?

Sarcoplasmic reticulum Signup and view all the answers

What substance in the sarcoplasm provides energy for muscle contraction?

Glycogen Signup and view all the answers

Which type of myofilament is primarily composed of actin?

Thin myofilament Signup and view all the answers

Which structure penetrates the muscle cell to facilitate the contraction process?

T (transverse) tubules Signup and view all the answers

What describes the function of the sarcolemma in a muscle fiber?

It serves as the plasma membrane of the muscle fiber. Signup and view all the answers

What occurs when both the agonist and antagonist muscles contract simultaneously?

Movement is inhibited. Signup and view all the answers

What role does myoglobin serve in skeletal muscle fibers?

It stores oxygen. Signup and view all the answers

What is the primary function of skeletal muscles?

Facilitating movement of bones. Signup and view all the answers

What are the smaller cylinders found within a skeletal muscle fiber called?

Myofibrils Signup and view all the answers

What is the function of myoglobin in muscle fibers?

It stores oxygen for muscle contraction. Signup and view all the answers

Which part of the muscle fiber conveys impulses to release calcium ions?

T tubule Signup and view all the answers

What is the structural role of myofibrils in muscle fibers?

They are bundles of myofilaments that contract. Signup and view all the answers

What happens to the I band during the contraction of a sarcomere?

It decreases in length. Signup and view all the answers

What type of protein comprises thick filaments in muscle fibers?

Myosin Signup and view all the answers

Which structure in the sarcomere contains only thick myofilaments?

H band Signup and view all the answers

What is the role of ATP in muscle contraction?

It supplies energy for contraction. Signup and view all the answers

What is the primary difference between thick and thin myofilaments?

Thick filaments are thicker than thin filaments, which consist of actin. Signup and view all the answers

What occurs to the Z lines during muscle contraction?

They move inward. Signup and view all the answers

Which component is specifically responsible for storing calcium ions in muscle fibers?

Sarcoplasmic reticulum Signup and view all the answers

What is the term for the continuous sliding action of myosin and actin filaments during muscle contraction?

Ratchet mechanism Signup and view all the answers

Which of the following is NOT a source of energy for muscle contraction?

Amino acids Signup and view all the answers

How do muscle cells primarily replenish ATP after its initial stock is used up?

Creatine phosphate pathway Signup and view all the answers

Which ions are crucial for the process of muscle contraction?

Calcium and ATP Signup and view all the answers

As exercise duration increases, which energy source becomes more significant?

Energy from blood glucose Signup and view all the answers

Study Notes

Muscular System - Part 1

Muscle tissue types: smooth, cardiac, and skeletal. Each has a specific function.
Skeletal muscle structure: A bundle of skeletal muscle fibers called a fascicle. Within a fascicle, each fiber is surrounded by connective tissue, and the fascicle itself is also surrounded by connective tissue.
Muscle fibers (cells): Have a cylindrical shape. Inside the larger cylinder are smaller cylinders called myofibrils.

Muscular System - Part 2

ATP Production in Muscle Cells: Muscle cells store limited ATP.
- Once ATP is used up, the cell has three ways to make more:
  - Creatine Phosphate (CP) pathway
  - Fermentation
  - Cellular Respiration
The Creatine Phosphate Pathway: The simplest and fastest way for muscles to make ATP. It's used at the beginning of exercise and only provides ATP for about 15 seconds.
Fermentation: Anaerobic process that produces 2 ATP by breaking down glucose to lactate. Used during short-term, intense exercise when oxygen is low. This process can cause muscle aches and fatigue due to lactate buildup.
Cellular Respiration: Slowest but most efficient method of making ATP. It uses oxygen to break down glucose or fatty acids for large amounts of energy. Occurs in the mitochondria and requires oxygen. Myoglobin in muscle cells delivers oxygen directly to the mitochondria.

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Description

Explore the fundamentals of the muscular system in this quiz, covering muscle tissue types, skeletal muscle structure, and ATP production in muscle cells. Learn about cellular respiration, fermentation, and the creatine phosphate pathway as energy sources for muscle activity.