GENERAL HISTOLOGY

MUSCLE

SKELETAL MUSCLE

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
when skeletal muscle is fully contracted, the ____ are closer to the thick filament
A
H
B
Z
C
synaptic cleft
D
sarcomere
Explanation: 

Detailed explanation-1: -Sliding Filament Theory According to this theory, myosin filaments use energy from ATP to “walk” along the actin filaments with their cross bridges. This pulls the actin filaments closer together. The movement of the actin filaments also pulls the Z lines closer together, thus shortening the sarcomere.

Detailed explanation-2: -During contraction, the myosin heads extend from the thick filament surface and attach to actin in the thin filaments, causing the filaments to slide past each other in a cyclic, ATP-driven process.

Detailed explanation-3: -The Sliding Filament Model of Contraction When signaled by a motor neuron, a skeletal muscle fiber contracts as the thin filaments are pulled and then slide past the thick filaments within the fiber’s sarcomeres. This process is known as the sliding filament model of muscle contraction (Figure 10.10).

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