Download Skeletal Muscles

10/7/2010
Skeletal Muscles
Week 4
Learning Objectives
1. Identify on A.D.A.M. figures and on human models the
muscles listed in the lab assignment.
2. Name the origin and insertion of individual skeletal muscles
and describe the actions produced by contraction of each
muscle.
3. Describe the microscopic anatomy of the 3 muscle types, and
answer questions about each, such as:
1.
2.
3.
Which type of muscle is under voluntary control...involuntary
control?
Why are there striations on skeletal muscle and cardiac muscle, and
not on smooth muscle fibers?
List at least two different organs in which you would find smooth
muscle, and describe it’s function.
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(begins on p. 49)
1. Histology of the 3 muscle tissue types (p. 50)
2. ADAM dissection of muscular system (p. 57)
3. Study of models (keys begin p. 71)
– Muscle man
– Muscle arm
– Muscle leg
4. Intro. to Biomechanics (p. 65)
Read pp. 310-312 in the textbook and complete the
pre-lab assignment for Thursday (p. 61-64)
Muscles may be named according to:
•
•
•
•
•
•
# parts - eg. Biceps brachii
origin & insertion - eg. Sternocleidomastoid
direction of fibers - eg. External oblique
location - eg. Supraspinatus
shape of muscle - eg. Deltoid
function - eg. Pronator teres
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Using
ADAM Tools
extract
Navigator icon
highlight
Click on muscle
for name
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Guide to Muscle “Dissection” p. 57
• Dissect from superficial layers to deep
• Practice this information:
– Origin and insertion (know your skeleton)
– Principle action
– Synergist/agonist muscles
• See Glossary (p. 51-52)
• Labeling exercise (pp. 54-55)
Origin, Insertion, & Action
Origin = least movable end
Insertion = more movable end
Action = when muscle shortens
• See Muscle Matching Quiz
assignment in packet.
• Use Ch. 11 in textbook to study
for quizzes.
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Muscle Matching Quiz
• Next Thursday, at the start of lab (1st 15 min)
Muscle name
Levator lapsanskii
Origin/Insertion
__a___
Action
__1___
Origin/Insertion:
a. San Diego, CA/Ferndale, WA
Action:
1. pulls students' legs, and elevates stress!
Preview: Musculoskeletal Interactions
Which end of the biceps brachii
moves when it contracts?
Origin
Insertion
Why does the biceps brachii apply
effort to the bone so close to the
elbow?
How would the workload change
if the object was balanced on the
middle of the forearm?
How would the workload change
if the biceps brachii attached to
the forearm at the wrist?
p. 59
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Thursday
Learning Objective:
Identify and describe (with examples) the 3 classes of levers
functioning in the body as a result of the interaction
between the skeletal and muscular systems.
Review: Movement at Joints
3 Major Types of Joints
• Fibrous (synarthrotic)
• Cartilagenous (amphiarthrotic)
• Synovial (diarthrotic)
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Introduction to Biomechanics
• Muscles and bones
work together
around joints as
systems of levers.
• Biological lever
systems are
designed either for
power or speed.
Figure on p. 59
Levers
p. 65
Identify the lever, fulcrum (F), effort arm (E), and
resistance arm (R).
In which situation would you be working at a
mechanical advantage (for power)?
MA = Effort arm (l)
Resistance arm (l)
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• The ratio of effort arm
to resistance arm
determines the power.
• A low resistance arm to
effort arm ratio
provides high power
but low speed
• A high resistance arm
to effort arm ratio
provides high speed
but lower power.
R:E = 2:1
Power
R:E = 5:1
Speed
p. 59
Classification of Levers p. 66
Class of Lever
Relationship of F, R, E
(1,2,3)
R
Example
E
Class I
Extension of head
F
R
Class II
E
F
Opening jaw against
resistance
E
Class III
F
R
Flexing forearm
Answer the questions and complete the table on pp. 67-69
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Next Week
• Pre-lab Assignment: Cranial Nerves and PNS;
Brain dissection, pp. 81-86.
• Nervous System anatomy
• Other preparations:
– Brain dissection - Tuesday (AVOID CONTACT LENSES)
– Brain Structure & Function Table (p. 96)
– Reflex Arc (p. 97) and worksheet (p. 101)
• Muscle Matching Quiz (Thursday)
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