Both do have actin and myosin.
Within each skeletal muscle fiber are hundreds of lengthwise subdivisions called myofibrils.
Myofibrils are made up of bundles of the protein filaments (myofilaments) that are responsible for muscle contraction: thin filaments: made of the protein actin, and
thick filaments: made of the protein myosin.
These are visible using a microscope.
The internal organization of actin and myosin in smooth muscle is different from that in the striated muscles.
Smooth muscle cells: are long and slender, are spindle shaped, with a single, central nucleus, have scattered myosin fibers, with more heads per thick filament and have actin filaments attached to dense bodies.
These can not be seen using a microscope and that is why they are also called smooth muscle fibers.
The filament connected to the Z line in a muscle cell is thin filament, specifically actin filament. Thick filaments (myosin) are connected to the M line in the sarcomere.
The thin filament sites remain open to the binding and stroke of the thick filament and there would be no muscle relaxation without the reuptake of Ca 2+ so the thin filament sites are closed.
This area is the A band of a sarcomere, which contains both thick myosin filaments and thin actin filaments. The overlapping of these filaments is essential for muscle contraction to occur through the sliding filament mechanism.
The thin filament that extends from the Z line toward the center of the sarcomere is primarily composed of actin, along with regulatory proteins such as tropomyosin and troponin. These filaments play a crucial role in muscle contraction by interacting with thick filaments (myosin) during the sliding filament mechanism. When a muscle is stimulated, calcium ions bind to troponin, causing a conformational change that allows myosin heads to attach to actin, resulting in contraction.
Structures that help to anchor the thick and thin filaments in place include the Z-discs (also called Z-lines or Z-bands) in skeletal muscle and the dense bodies in smooth muscle. These structures provide attachment points for the filaments and help maintain the organization and alignment of the muscle proteins during contraction.
There more thin filaments than thick filaments in smooth muscle. The ratio is of the thin to thick filaments in the smooth muscle is approximately 15:1.
The filament connected to the Z line in a muscle cell is thin filament, specifically actin filament. Thick filaments (myosin) are connected to the M line in the sarcomere.
Myosin is a protein that is not found in the thin filament. Myosin is a motor protein that is primarily found in the thick filament of muscle cells and is responsible for muscle contraction. The thin filament contains proteins such as actin, tropomyosin, and troponin.
M-line, causing overlap with the thick filament during muscle contraction. This results in the sarcomere shortening and overall muscle contraction.
In the sliding filament theory of muscle contraction, the thin filament (actin) slides over the thick filament (myosin). Myosin is responsible for pulling the actin filaments towards the center of the sarcomere during muscle contraction.
The thin filament of a myocardial cell is composed primarily of actin, tropomyosin, and troponin proteins. These proteins play a crucial role in regulating the contraction and relaxation of the heart muscle by interacting with the thick filament during the process of muscle contraction.
The length of the thick filament is the A band. The A band contains both thick and thin filament because they are overlapping each other. The H band is thick filament only, however, it only covers a portion of width of the thick filament.
Contraction or relaxation of muscle fibre, due to similar effect in sarcomere
Calcium ions bind to the thin filament ( actin ), turn it and expose the binding site to the thick filament (myosin ).
The thin filament sites remain open to the binding and stroke of the thick filament and there would be no muscle relaxation without the reuptake of Ca 2+ so the thin filament sites are closed.
When skeletal (or cardiac) muscle contracts, the thin and thick filaments in each sarcomereslide along each other without their shortening, thickening, or folding.
The two filaments involved are myosin and actin. Actin: is the framework and slides over the myosin filament when the muscle is shortened. myosin: is a thick filament Also a sacromere: is made up of the actin and myosin. It is the functional unit of a muscle fibre and extends from z line to z line. A muscle contraction: is many sacromeres shortening ( actin sliding over myosin)