Muscle Terminology Flashcards

Questions and Answers

What is the meaning of the prefix myo-?

Muscle (correct)

Above

Around

Flesh

What is the meaning of the prefix epi-?

Upon (correct)

Within

Flesh

Muscle

The structural and functional unit of skeletal muscle is called a/an:

Sarcoplasmic reticulum

Fascicle

Sarcomere (correct)

Myofibril

What happens if a muscle fiber is extensible but not elastic?

It would stretch but not return to its original shape. Signup and view all the answers

What would occur if actin filaments were incapable of sliding past the myosin filaments?

Contraction would not occur, and tension would not be generated. Signup and view all the answers

If you consumed pufferfish that was not prepared correctly, what effect would it have on your muscle fibers?

The poison would prevent action potentials from occurring along the sarcolemma. Signup and view all the answers

Which membrane protein is involved in active transport?

Na+/K+ pump Signup and view all the answers

If the cytosol loses K+ ions through leak channels, how will it change?

It will become more negative. Signup and view all the answers

For every ATP split into ADP and a phosphate, the Na+/K+ pump moves _ out of the cell and __ into the cell.

3 Na+; 2 K+ Signup and view all the answers

What is the narrow space between the axon terminal and the motor end plate called?

Synaptic cleft. Signup and view all the answers

What happens when acetylcholine (ACh) receptors are stimulated by ACh?

Sodium ions enter the muscle fiber. Signup and view all the answers

What is the end-plate potential?

A depolarization caused by sodium ion movement into the cytosol. Signup and view all the answers

How does multiple sclerosis affect skeletal muscle stimulation?

The muscle will not be stimulated and therefore will not contract. Signup and view all the answers

What is the result of an overdose of Botox?

Muscle paralysis at the site of injection. Signup and view all the answers

What are the components of a triad?

Two terminal cisternae of the sarcoplasmic reticulum (SR) and one T-tubule. Signup and view all the answers

What does excitation-contraction coupling lead to?

An increase of calcium ion concentration in the cytosol of the muscle fiber. Signup and view all the answers

What is the effect of Tetrodotoxin on action potential generation?

There will be no action potential generated in the muscle fiber. Signup and view all the answers

When does a crossbridge form?

A myosin head binds to actin. Signup and view all the answers

Which step occurs immediately before the power stroke in the crossbridge cycle?

A crossbridge forms. Signup and view all the answers

What happens as myosin heads complete the power stroke?

Actin filaments slide toward the M line of the sarcomere. Signup and view all the answers

What causes myosin to detach from actin?

An ATP molecule binds to myosin. Signup and view all the answers

In the absence of ATP in muscles, what is most likely to occur?

Some myosin heads will remain attached to actin molecules but are unable to perform a power stroke. Signup and view all the answers

What can cause muscle relaxation?

End of neural stimulation. Signup and view all the answers

What occurs when the sarcolemma repolarizes?

The inside of the sarcolemma is more negatively charged than the outside. Signup and view all the answers

What causes rigor mortis?

ATP depletion, which leads to high cytosolic calcium and inability of crossbridges to detach. Signup and view all the answers

Study Notes

Myo- means "muscle."
Epi- signifies "above," "upon," or "over."
Sarco- refers to "flesh."
Peri- means "around."
Endo- denotes "within" or "inner."

Muscle Structure and Connective Tissues

A sarcomere is the skeletal muscle's basic structural and functional unit.
The perimysium is the connective tissue surrounding a fascicle.
The epimysium covers the outer layer of the entire muscle.
The endomysium surrounds an individual muscle fiber.
Myofibrils are the contracting parts of muscle fibers.

Muscle Fiber Properties

Extensibility allows muscle fibers to stretch, while elasticity enables them to return to their original shape; lack of elasticity means stretching without returning to form.

Muscle Contraction Mechanisms

If actin cannot slide past myosin, muscle contraction and tension generation are impossible.
Tetrodotoxin from pufferfish blocks sodium ion channels, preventing action potentials in muscle fibers and causing paralysis.

Ion Transport and Resting Potential

The Na+/K+ pump is crucial for active transport across membranes.
Loss of K+ ions through leak channels results in a more negative cytosol.
For every ATP used, the Na+/K+ pump transports 3 Na+ out and 2 K+ into the cell.

Synaptic Transmission

The gap between the axon terminal and motor end plate is called the synaptic cleft.
Stimulation of acetylcholine (ACh) receptors leads to sodium ions entering the muscle fiber, resulting in depolarization known as the end-plate potential.

Impacts of Neural Conditions on Muscle Function

Demyelination in conditions like multiple sclerosis blocks action potentials, preventing muscle contraction.
An overdose of botulinum toxin blocks ACh release, causing muscle paralysis.

Triads and Calcium Dynamics

A triad consists of two terminal cisternae of the sarcoplasmic reticulum (SR) and one T-tubule.
Excitation-contraction coupling increases calcium ion concentration in the muscle fiber cytosol.
Tetrodotoxin prevents action potential generation in muscle fibers.

Crossbridge Cycling

A crossbridge occurs when a myosin head binds to actin.
Formation of a crossbridge precedes the power stroke in the crossbridge cycle.
During the power stroke, actin filaments slide toward the M line of the sarcomere.

Myosin and ATP Interaction

Myosin detachment from actin is facilitated by the binding of ATP to myosin.
In ATP absence, myosin heads remain attached to actin but cannot perform the power stroke.
Muscle relaxation arises from the end of neural stimulation.

Resting Membrane Potential and Rigor Mortis

After repolarization, the inside of the sarcolemma becomes more negatively charged than the outside.
Rigor mortis, the stiffening of muscles post-death, results from ATP depletion and elevated cytosolic calcium, preventing crossbridges from detaching.

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Description

Test your knowledge of muscle-related terminology with these flashcards. Each card covers important prefixes and the structure of skeletal muscle, including key definitions and functions.