muscular system: muscles (chapter 11) lecture materials for amy

Muscular System: Muscles(Chapter 11)

Lecture Materials

for

Amy Warenda Czura, Ph.D.

Suffolk County Community College

Eastern Campus

Primary Sources for figures and content:

Marieb, E. N. Human Anatomy & Physiology 6th ed. San Francisco: Pearson BenjaminCummings, 2004.

Martini, F. H. Fundamentals of Anatomy & Physiology 6th ed. San Francisco: PearsonBenjamin Cummings, 2004.

Amy Warenda Czura, Ph.D. 1 SCCC BIO130 Chapter 11 Lecture Slides

Muscle Organization-groups of fibers organized into fascicles-fibers in fascicle run parallel to fascicle, but

fascicle can be arranged in 4 differentshapes with respect to tendon:

1. Parallel muscles-fascicles run parallel to length of muscle-most skeletal muscles arranged this way-able to change length extensively-can move load over a great distance


2. Convergent muscles-fascicles spread out like fan on one end and

converge to single point on other-produces less tension and distance than

parallel muscle but- independent contraction of fascicles can

produce different movements from same muscle

-provides versatility


3. Pennate muscles (“feather like”)-fascicles are arranged at an angle to tendon

A. Unipennate =fascicles angled on one side of tendon

B. Bipennate =tendon in middle with angled fascicles oneither side

C. Multipennate =branched tendon with fascicles organizedaround each branch-pennate muscles produce more tension than

parallel muscles but cannot move as far


4. Circular muscles (sphincters)-concentric arrangement of fascicles-function to decrease diameter of openings,

guard entrances and exits

Muscle Terminology

Origin = where the fixed end of the muscleattaches to bone, cartilage, or CT

Insertion = where the moveable end attaches

Action = the specific movement produced bythe muscle during contraction


Muscles often work in groups to increasetension or fine tune movement.

Different muscles serve different functions:

Agonist = prime mover, muscle mostresponsible for the specific action

Synergist = a muscle with the same action asthe agonist, assists agonist at thebeginning of contraction when fiberlength is not optimal for agonist

Antagonist = a muscle whose action opposesthe agonist: produces the oppositeaction to fine tune movement by theagonist


Names of muscle derived from aspects of theirfeatures:

1. Location: named for part of body wherelocated e.g. Brachii, Abdominis

2. Fascicle organization: named for howfascicles are organized with respect tobody e.g. Rectus = straight

Oblique = angle3. Relative position: named for depth when

layered e.g. Externus/ Superficialis =top, surface

Internus/ Profundus =deep4. Structure, Size and Shape: A. Number of tendons

e.g. triceps, biceps B. Shape of muscle

e.g. trapezius = trapezoid deltoid = triangle soleus = fish


C. Size of muscle relative to othersMajor = biggerMaximus = biggestLongus = longVastus = great

5. Origin and Insertion: name for regions ofattachment, origin first, insertion seconde.g. Sternocleidomastoidorigin = manubrium of sternum and

medial clavicleinsertion = mastoid process

6. Action: named for action performed and region acted upone.g. Extensor digitorum

Usually multiple naming schemes arecombined to name the muscle:e.g. flexor carpi ulnaris

*Individual muscles, origins, insertions andactions will be examined in detail in lab!


muscular system: muscles (chapter 11) lecture materials for amy

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