Muscles - Biomechanics, Chapter 1

What are the three types of muscle?

Smooth, cardiac, and skeletal

Where is smooth muscle located?

In organs and blood vessels

Where is cardiac muscle located?

The heart

Where is skeletal muscle located?

Bones, causing them to move

What are the four properties of skeletal muscle?

Extensibility, elasticity, contractibility, excitability

Skeletal muscles attach to bones by what?

Tendons

What is the muscle origin for skeletal muscle?

Attached to proximal bone of a joint

What is the muscle insertion for skeletal muscle?

Attached to distal bone of a joint

What are the four functions of skeletal muscle?

Movement, protection, joint support, heat production

What do smooth muscles typically do inside of blood vessels?

Open and close the lumen to assist with blood flow

What is peristalsis?

A rhythmic contraction helping with the opening and closing of lumen

What does Systole refer to?

Contraction of cardiac muscle

What does Diastole refer to?

Period when cardiac muscle relaxes

Finish the rest of the skeletal muscle forms:

Fusiform, Quadrate, Triangular…

Unipennate, bipennate, multipennate, and longitudinal

What are most skeletal muscles?

Fusiform or pennate

What are the three types of muscle contraction?

Concentric, eccentric, isometric

What does the SAID principle stand for?

Specific Adaptation to Imposed Demands

What does the SAID principle mean?

Muscle is able to change in size and strength based on the demands placed on them

All skeletal muscle contains what? What does Fascicular arrangement do?

Fascicles; Determines name

What kind of muscle shape is this? Describe it.

Digastric; two muscle bellies with an intermediate tendon

What kind of muscle shape is this? Describe it.

Fusiform; Spindle-shaped

What kind of muscle shape is this? Describe it.

Multipennate; fibers arranged at multiple angles

What kind of muscle shape is this? Describe it.

Sphincter; Circular muscle surrounding openings

What kind of muscle shape is this? Describe it.

Bipennate; Fibers attached on both sides of tendon

What kind of muscle shape is this? Describe it.

Unipennate; Fibers attached on one side of tendon

What kind of muscle shape is this? Describe it.

Tricipital; muscle with three heads

What kind of muscle shape is this? Describe it.

Triangular (convergent); Fibers fan toward one tendon

What kind of muscle shape is this? Describe it.

Strap; Long parallel fibers with tendinous insertions

What are tendon sheaths?

Connective tissue covering tendons, protecting them from wear and tear

What is the main muscle producing a particular movement called?

Prime mover, or agonist

What is a muscle helping an agonist accomplish its action called?

Synergist

What is the agonist typically opposed by with another muscle?

Antagonist

What is the name of a muscle holding a bone in place while another muscle performs its function?

Action is fixation, muscle is fixator

What type of connective tissue is skeletal muscle encased in?

Epimysium

What is the fibrous sheath that wraps around bundles of muscle fibers called?

Perimysium

Within the perimysium, what is the connective sheath called enclosing those muscle fibers?

Endomysium

What is the contractile element of muscle?

Myofibrils

Individual myofibrils are enclosed by a viscous material known as what? After that, they’re then wrapped in a membrane known as what?

Sarcoplasm; Sarcolemma

What are the functional units of skeletal muscle?

Sarcomeres

What are the two types of skeletal muscle fibers?

Fast-twitch and slow-twitch fibers

What is the green zigzag line on the left and right called?

Z-line

What is the middle portion called? (with the 3 lines)

H-zone

Before both of the z-lines, what is that portion called?

A-band

After the thin actin filaments and before the a-band, what is that portion called?

I-band

From the left z-line to the right z-line, what is that whole section called?

Sarcomere

What are the characteristics of fast-twitch fibers?

Large and white, appear in muscles used to perform strength activities

What are the characteristics of slow-twitch fibers?

Small and darker red color, appear in muscles involved in endurance activities