Muscle Contraction: Sarcomeres
Name: michelle barajas
Model 1: Anatomy of a Sarcomere
The sarcomere is the functional (contractile) unit of skeletal muscle. It is the region of a
myofibril between two Z discs. Each sarcomere is approximately 2um long.
:
:
I
A
I
H
M
Z
Actin
myosin
QUESTIONS:
(thin)
(thick)
1. Label the thick horizontal filament THICK filament.
2. Label the thin horizontal filament THIN filament.
3. How many sarcomeres are shown in the above model?
3
4. Based on your observations of the location of thick and thin filaments,
describe each of the following:
a) A
band :the thick & thin line
b) I band : only the thin filaments (actin)
c) H zone : only the thick bands(myosin)
d) Z disc : Z- lines, where the actins connect
e) M line where
middle of the myosin
5. Describe how the H zone differs from the A band.
Hzone is only the myosin & A band is myosin Gactin
6. How many sarcomeres do you think are in a muscle cell found in your quadriceps?
10,000
7. Do you think you would have more or fewer sarcomeres in an eye muscle?
more
