Download Labs 14

Muscle Labs
Lab 14
Muscles Overview
Muscle Practical
• Tuesday 11/20
• 50 points
• Covers all the muscles on the Muscle List
(available on the website and in the syllabus:
• Most of the labs for the next two weeks will
consist of looking at models and diagrams
to learn the muscles.
• The models will be the same models used
on the practical quizzes
• I will post these lectures on the website
Muscle exam
• The muscle exam will include some
muscle labeling from the first half of the
muscles
– head and face; neck; chest; abdominal; and back and
shoulder , upper arm; lower arm; hip and thigh; upper
leg; and lower leg
– You need to know origins and insertions for the ones
listed in bold only
– Know general functions
• Uses about half models (little men, torsos, hand,
foot, arms, legs) and half B&W book pictures
Divisions of the Muscular
System
1. Axial muscles:
– position head and spinal column
– move rib cage
– 60% of skeletal muscles
2. Appendicular muscles:
– support pectoral and pelvic girdles
– support limbs
– 40% of skeletal muscles
Origins and Insertions
• Muscles have 1 fixed point of attachment
(origin) and 1 moving point of attachment
(insertion)
• Most muscles originate or insert on the
skeleton
• Origin is usually proximal to insertion
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Origin and Insetaions
Actions
• Fixed end in (b) below is the origin, while
moving end is the insertion
• Movements produced by muscle
contraction
• Body movements
– e.g., flexion, extension, adduction, etc.
• Described in terms of bone, joint, or region
Figure 10–13
Muscle Interactions
• Muscles work in groups to maximize
efficiency
• Smaller muscles reach maximum tension
first, followed by larger, primary muscles
Muscle Terminology
Based on Function
• Synergist:
– a smaller muscle that assists a larger agonist
– helps start motion or stabilize origin of agonist
(fixator)
Muscle Terminology
Based on Function
• Agonist (prime mover):
– produces a particular movement
• Antagonist:
– opposes movement of a particular agonist
Muscle Opposition
• Agonists and antagonists work in pairs:
– when 1 contracts, the other stretches
– i.e., flexors–extensors, abductors–adductors,
etc.
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Names of Skeletal Muscles
How does the name of a
muscle help identify its
location, appearance, or
function?
Descriptive Names
for Skeletal Muscles
1.
2.
3.
4.
5.
6.
Location in the body
Origin and insertion
Fascicle organization
Relative position
Structural characteristics
Action
Origin and Insertion
• First part of name indicates origin
• Second part of name indicates insertion:
– e.g., genioglossus muscle
• Correct names of muscles include the
term muscle
• Exceptions:
– platysma
– diaphragm
Location in the Body
• Identifies body regions:
– e.g., temporalis muscle
Fascicle Organization
• Describes fascicle orientation within
muscle:
– rectus (straight) = parallel to body or limb
– transversus = perpendicular to the midline
– oblique
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Relative Position
• Externus (superficialis):
Structural Characteristics
• Number of tendons (or heads):
– visible at body surface
• Internus (profundus):
– bi = 2, tri = 3
• Shape:
– deep muscles
– trapezius, deltoid, rhomboid
• Extrinsic:
– muscles outside an organ
• Size…
• Intrinsic:
– muscles inside an organ
Names for Muscle Size (1 of 2)
•
•
•
•
•
Longus = long
Longissimus = longest
Teres = long and round
Brevis = short
Magnus = large
Action
Names For Muscle Size (2 of 2)
•
•
•
•
Major = larger
Maximus = largest
Minor = small
Minimus = smallest
Naming Skeletal Muscles
• Movements:
– e.g., flexor, extensor, retractor
• Occupations or habits:
– e.g., risor = laughter
Table 11–1 (1 of 2)
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Naming Skeletal Muscles –
contiuned
Lab 14
• Examine muscle structure
• Look at and draw NMJ slide
• Drawing and Reviews Sheet due next
week
• Due next Thursday
Table 11–1 (2 of 2)
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