Question 1

The thick and thin filaments are made up of _, respectively.

Accepted Answer

Thick filaments are primarily composed of the protein myosin, while thin filaments are primarily composed of the protein actin. These proteins are crucial for muscle contraction.

Question 2

What is the correct order of structures as you move from outside a muscle cell, to deep inside it?

Accepted Answer

The correct order from the outside of a muscle cell moving inward is fiber (the muscle cell itself), myofibril (a component of the muscle fiber), and myofilament (the filaments within the myofibrils that contract).

Question 3

Tendons differ from ligaments in that .

Accepted Answer

Tendons and ligaments both connect to bones but serve different functions: tendons attach muscle to bone, facilitating movement, while ligaments connect bone to bone, providing stability to joints.

Question 4

The function of the neuromuscular junction is to .

Accepted Answer

The neuromuscular junction is a synapse between a motor neuron and a skeletal muscle fiber, where the motor neuron transmits a signal to the muscle fiber, causing it to contract.

Question 5

This contractile protein forms the thin filaments.

Accepted Answer

Actin is the protein that forms the thin filaments in muscle fibers, which are essential for muscle contraction.

Question 6

Each of the elements that make up a skeletal muscle is surrounded by connective tissue. Which words below correctly pair the connective tissue layer with the corresponding muscle structure?

Accepted Answer

The answer of Each of the elements that make up...

Question 7

At the neuromuscular junction, the electrical signal of the nerve .

Accepted Answer

At the neuromuscular junction, the electrical signal (action potential) arriving at the axon terminal of a motor neuron causes the release of the neurotransmitter acetylcholine (ACh) into the synaptic cleft, which then binds to receptors on the muscle cell membrane, leading to muscle contraction.

Question 8

From gross to microscopic, the parts of a muscle are .

Accepted Answer

The correct order from the largest to the smallest structure in muscle anatomy is muscle (the whole muscle), fascicle (a bundle of muscle fibers), and fiber (individual muscle cell).

Question 9

An aponeurosis is .

Accepted Answer

An aponeurosis is similar to a tendon in function, as both serve to connect muscles to bones or other structures, but an aponeurosis is a flat, broad tendon-like sheet.

Question 10

This contractile protein is shaped like a golf club.

Accepted Answer

The answer of This contractile protein is shaped like a...

Question 11

This indentation of the sarcolemma carries electrical signals deep into the muscle cells.

Accepted Answer

T tubules, or transverse tubules, are invaginations of the sarcolemma that carry electrical signals deep into the muscle cells, ensuring that the entire muscle cell responds to a nerve impulse simultaneously.

Question 12

A muscle fiber is _ .

Accepted Answer

A muscle fiber is essentially a muscle cell, which is a long, cylindrical, multinucleated cell that makes up skeletal muscles.

Question 13

The neuromuscular junction consists of .

Accepted Answer

The neuromuscular junction is where the axon terminal of a motor neuron comes into close proximity to a muscle fiber, allowing for the transmission of nerve impulses to the muscle.

Question 14

A neuron and all the muscle fibers it stimulates is called a _.

Accepted Answer

A motor unit consists of a single neuron and all the muscle fibers it innervates, allowing for coordinated muscle contraction.

Question 15

This strong, cord-like structure attaches muscles to bones.

Accepted Answer

Tendons are the strong, cord-like structures that attach muscles to bones, allowing for the transmission of force from the muscle to the bone to facilitate movement.

Question 16

Sarcomeres consist of _.

Accepted Answer

Sarcomeres are the basic contractile units of muscle fiber, consisting of an orderly arrangement of actin and myosin filaments. This arrangement allows for muscle contraction through the sliding filament theory.

Question 17

The actual contractile units of muscles extend from Z disc to Z disc. They are _.

Accepted Answer

Sarcomeres are the structural and functional units of a muscle fiber, extending from one Z disc to another. They are responsible for muscle contraction.

Question 18

The dark band of skeletal muscle consists of .

Accepted Answer

The dark band of skeletal muscle, known as the A band, consists of both thick and thin filaments. This region is where the thick and thin filaments overlap, contributing to the muscle's striated appearance.

Question 19

Terminal cisterns _.

Accepted Answer

Terminal cisterns are enlarged areas of the sarcoplasmic reticulum (a form of smooth endoplasmic reticulum) in muscle cells that store calcium ions, which are essential for muscle contraction. They are not directly involved in storing acetylcholine, carrying action potentials, or linking the nervous system to the muscle cell in the way described by the other options.

Question 20

The space between the axon terminal and the sarcolemma of a muscle fiber is called the .

Accepted Answer

The space between the axon terminal of a neuron and the sarcolemma of a muscle fiber is known as the synaptic cleft. This gap is crucial for the transmission of neural signals to the muscle, leading to muscle contraction.

Quiz 12: Microscopic Anatomy and Organization of Skeletal Muscle