ch 10 lecture outline a

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Copyright © 2010 Pearson Education, Inc.

Three Types of Muscle Tissue

1. Skeletal muscle tissue:

Attached to bones and skin

Striated Voluntary (i.e., conscious control)

Powerful

Primary topic of this chapter





2. Cardiac muscle tissue:

Only in the heart

Striated Involuntary

More details in Chapter 18





3. Smooth muscle tissue:

In the walls of hollow organs, e.g., stomach,

urinary bladder, and airways

Not striated

Involuntary

More details later in this chapter




Special Characteristics of Muscle Tissue

Excitability (responsiveness or irritability):

ability to receive and respond to stimuli

Contractility: ability to shorten when

stimulated

Extensibility: ability to be stretched

Elasticity: ability to recoil to resting length




Muscle Functions

1. Movement of bones or fluids (e.g., blood)

2. Maintaining posture and body position

3. Stabilizing joints

4. Heat generation (especially skeletal muscle)




Skeletal Muscle

Each muscle is served by one artery, one

nerve, and one or more veins




Skeletal Muscles: Functional Groups

1. Prime movers

Provide the major force for producing a

specific movement

2. Antagonists

Oppose or reverse a particular movement




Skeletal Muscles: Functional Groups

3. Synergists

Add force to a movement

Reduce undesirable or unnecessarymovement

4. Fixators

Synergists that immobilize a bone or muscle¶s origin




Naming Skeletal Muscles

Location²bone or body region associatedwith the muscle

Shape²e.g., deltoid muscle (deltoid =

triangle)

Relative size²e.g., maximus (largest),minimus (smallest), longus (long)

Direction of fibers or fascicles²e.g., rectus(fibers run straight), transversus, and oblique(fibers run at angles to an imaginary definedaxis)




Naming Skeletal Muscles

Number of origins²e.g., biceps (2 origins)

and triceps (3 origins)

Location of attachments²named according to

point of origin or insertion

Action²e.g., flexor or extensor, muscles that

flex or extend, respectively




Muscle Mechanics: Arrangement of Fascicles

Circular

Fascicles arranged in concentric rings (e.g.,

orbicularis oris)

Convergent

Fascicles converge toward a single tendon insertion

(e.g., pectoralis major)

Parallel

Fascicles parallel to the long axis of a straplike

muscle (e.g., sartorius)




Muscle Mechanics: Arrangement of Fascicles

Fusiform

Spindle-shaped muscles with parallel fibers

(e.g., biceps brachii)

Pennate

Short fascicles attach obliquely to a central

tendon running the length of the muscle (e.g.,

rectus femoris)



Copyright © 2010 Pearson Education, Inc. Figure 10.1

(a)

(b)

(e)

(d)

(g)

(f)

(c)

Circular

(orbicularis oris)

(b) Convergent

(pectoralis major)

(c) Parallel

(sartorius)

(d) Unipennate

(extensor

digitorum

longus)

(f) Fusiform

(biceps brachii)

(g) Multipennate

(deltoid)

(e) Bipennate

(rectus femoris)




Muscle Mechanics: Lever Systems

Components of a lever system

Lever²rigid bar (bone) that moves on a fixed

point or fulcrum (joint)

Effort²force (supplied by muscle contraction)

applied to a lever to move a resistance (load)

Load²resistance (bone + tissues + anyadded weight) moved by the effort

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