Transcript Notes: Intro to Muscular System

Muscular System
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Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The Muscular System
 Main function of a muscle:
Contraction (shortening)
Because muscles can contract:
The main functions of the muscular system are:
Movement
Maintains Posture
Stabilizes Joints
Generates Heat
Controls Openings (sphincters)
Expressions
Protection (reflexes)
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
 Three basic muscle types are found in the body
 Skeletal muscle
 Cardiac muscle
 Smooth muscle
can you distinguish which is which?
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Characteristics of Muscles
 Skeletal and smooth muscle cells are elongated
***(a muscle cell is also referred to as a muscle fiber)
Some skeletal muscle cells can be up to a foot long in length
 All muscles share some terminology
If you see myo- mys- or sarc- you think MUSCLE!
 Prefixes myo and mys refer to “muscle”
 Prefix sarco refers to “flesh”
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Comparison of Skeletal, Cardiac,
and Smooth Muscles
Table 6.1 (1 of 2)
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Comparison of Skeletal, Cardiac,
and Smooth Muscles
Table 6.1 (2 of 2)
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Terminology Review
 Endo-
Inside, Within (endoskeleton)
 Peri-
Around, surround (perimeter)
 Epi-
On, over, above (epidermis)
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Our Focus: SKELETAL MUSCLE (Striated)
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Skeletal Muscle Characteristics
 Attached to the skeleton
 Attached by tendons to bones (or aponeuroses)
 Cells are multinucleate (many nuclei)
 Striated (have visible banding)
 Strong force
 Tire easily (muscle fatigue)
 Voluntary—you control them (exception = reflexes)
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Connective Tissue Wrappings of Skeletal Muscle
 Cells are surrounded and bundled by connective tissue
 Endomysium—encloses a single muscle fiber
 Perimysium—wraps around a group of muscle fibers
forming a fascicle (bundle of muscle fibers)
 Epimysium—covers the entire skeletal muscle (many
fascicles)
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Connective Tissue Wrappings of Skeletal Muscle
Figure 6.1
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Skeletal Muscle Attachments

Epimysium blends into a
connective tissue attachment at
the ends of muscles
2 Types
1. Aponeuroses—sheet-like
structures of connective
tissue (sometimes referred
to as fascia)

Attach muscles to bones,
cartilages, or connective
tissue coverings
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Skeletal Muscle Attachments
2. Tendons—cord-like
structures
 Mostly collagen
fibers
 Often cross a joint
due to toughness
and small size
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings