Muscle contraction is the activation of tension-generating sites within muscle fibers. Muscles are composed of two major protein filaments: a thick filament composed of the protein myosin and a thin filament composed of the protein actin. Muscle contraction occurs when these filaments slide over one another in a series of repetitive events. Components of muscle contraction: Sarcomere Actin Myosin Z-bands I-bands A-band H-zone The thick filaments and the thin filaments within myofibrils overlap in a structured way, forming units called sarcomeres The 'H zone' is at the centre of the A band of each sarcomere. As shown below, this is the region in which there are only thick filaments, and no thin filaments Sarcomere Bands : A-band A band' is a relatively darker area within the sarcomere that extends along the total length of the thick filaments The 'I band' is the region between adjacent A bands, in which there are only thin filaments, and no thick filaments.  From all the above disscussion we can say that muscle contraction have some major components like mayosin and actin. Which form the bands on the sarcomere by interdigitating..

1. Muscle contraction is
the activation of
tension-generating sites
within muscle fibers.
Structure of muscle contraction
AYESHA SAFDAR
Uog.pk

2. Muscle fiber:

3. Mayofibril:

4. Striated fiber :

5. Muscles are composed of two major protein filaments: a thick filament composed of the
protein myosin and a thin filament composed of the protein actin. Muscle
contraction occurs when these filaments slide over one another in a series of repetitive
events.
Actin

6. Components of muscle contraction:
 Sarcomere
Actin
Myosin
Z-bands
I-bands
A-band
H-zone

7. The thick filaments and the thin
filaments within myofibrils overlap in a structured way, forming
units called sarcomeres.
Sarcomeres are also described in
terms of the bands / zones within
which one or both of the two
filaments occur

8. Actin:

9. Myosin:

10. The 'H zone' is at the centre of the A
band of each sarcomere. As shown
below, this is the region in which there
are only thick filaments, and no thin
filaments.
H-Zone:

11. Sarcomere Bands :
A-band
A band' is a relatively darker area within
the sarcomere that extends along the
total length of the thick filaments.

12. The 'I band' is the region between
adjacent A bands, in which there are
only thin filaments, and no thick filaments.
I- Band:

13. Overall Structure:

14. SUMMARY
From all the above disscussion we can say that muscle
contraction have some major components like mayosin and
actin. Which form the bands on the sarcomere by
interdigitating..

15. THANKS
Ayesha Safdar
#29