Download Skeletal muscle fiber

Figure
19.1
Srructures found in skeletal muscle fibers (cells) (25Ox micrograph enlarged to 700x).
Skeletalmusclefiber (cell)
Nuclei
Striations(alternating
lightand dark)
Figure 19.2
Label the structures of a skeletal muscle.
Bone
4
Endomysium
Axon of motorneuron
Bloodvessel
Musclefiber(singlecell)
r40
Filaments(actinand myosin)
Figure 19.3
Structures of a skeletal muscle fiber.
Cisternaeof
I
reticulumI frirO
sarcoplasmic
Transversetubule
I
Sarcoplasmic
reticulum
Openingsinto
transversetubules
Mitochondria
Thickand thin
filaments
Sarcoolasm
7 . Examine the model of the skeletal muscle fiber and
locate the following:
sarcolemma
sarcoplasm
myofibril
myosin filament
actin filament
safcomefe
A band (dark)
I band (light)
Zline
sarcoplasmic
Nucleus
Sarcolemma
8 . Complete Part B of the laboratory report.
9 . Review the section entitled "Skeletal Muscle
Actions" in chapter 8 of the textbook.
1 0 . Locate the biceps brachii muscle and its origin and
insertion in the torso and in your own body.
1 1 . Make various movements with your upper limb at
the shoulder and elbow. For each movement,
determine the location of the muscles functioning
as prime movers and as antagonists. (Remember,
when a prime movef contracts, its antagonist
must relax.)
L 2 . Complete Part C of the laboratory report.
reticulum
cisternae
transverse tubules
l4l
LaboratoryReport
Name
I g
Date
Section
SKELETAL MUScLE
STRUcTURE
PART A
Match the terms in column A with the definitions in column B. Place the letter of your choice in the space provided.
Column A
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
k.
L
Endomysium
Epimysium
Fascia
Fascicle
Myosin
Perimysium
Sarcolemma
Sarcomere
Sarcoplasm
Sarcoplasmicreticulum
Tendon
Transverse tubule
Column
B
1. Membranous channel extending inward from muscle fiber
membrane
2. Cytoplasm of a muscle fiber
3. Network of connective tissue that extends throughout the
muscular system
4. Layer of connective tissue that separates a muscle into small
bundles called fascicles
5. Cell membrane of a muscle fiber
6. Layer of connective tissue that surrounds a skeletal muscle
7. Unit of alternating light and dark striations between zlines
8. Layer of connective tissue that surrounds an individual muscle fiber
9. Cellular organelle in muscle fiber coffesponding to the
endoplasmic reticulum
10. Cordlike pafithat attaches a muscle to a bone
11. Protein found wirhin thick myofibril
12. A small bundle of muscle fibers
PART B
Provide the labels for the electron micrograph in figure 19.4.
1.
2.
3.
4.
143
Figure 19.4 IdentiS' the bands and lines of the striations in this transmission electron micrograph of relaxed sarcomeres
( l6.OOOx).using the terms provided.
Terms:
A band{dark)
I band (light)
Sarcomere
i
Z line
PART C
Complete the following statements:
1. The
of a muscle is usually attached to a fixed p^rt.
2. The
of a muscle is usually attached to a movable part.
3. The name bicePsmeans
4. The forearm is flexed at the elbow when the
muscle contfacts.
5. A muscle responsible for most of a movement is called a(n)
6. Assisting muscles are called
7. Antagonists are muscles that resist the actions of
in the opposite direction.
144
and cause movement