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Are there more thick filaments than thin filaments in smooth muscle?
Wiki User
∙ 9y ago
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.
Wiki User
∙ 9y ago
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How can smooth muscle contract if it has no striation or sarcomeres?
Actin and myosin are present in all three muscle types. In skeletal and cardiac muscle cells, these proteins are organized in sarcomeres, with thin and thick filaments. The internal organization of a smooth muscle cell is very different: • A smooth muscle fibre has no T tubules, and the sarcoplasmic reticulum (SR) forms a loose network throughout the sarcoplasm. Smooth muscle tissue has no myofibrils or sarcomeres. As a result, this tissue also has no striations and is called nonstriated muscle. • Thick filaments are scattered throughout the sarcoplasm of a smooth muscle cell. The myosin proteins are organized differently than in skeletal or cardiac muscle cells, and smooth muscle cells have more cross-bridges per thick filament. • The thin filaments in a smooth muscle cell are attached to dense bodies, structures distributed throughout the sarcoplasm in a network of intermediate filaments composed of the protein desmin. Some of the dense bodies are firmly attached to the sarcolemma. The dense bodies and intermediate filaments anchor the thin filaments such that, when sliding occurs between thin and thick filaments, the cell shortens. Dense bodies are not arranged in straight lines, so when a contraction occurs, the muscle cell twists like a corkscrew. • Adjacent smooth muscle cells are bound together at dense bodies, transmitting the contractile forces from cell to cell throughout the tissue. • Although smooth muscle cells are surrounded by connective tissue, the collagen fibres never unite to form tendons or aponeuroses as they do in skeletal muscles.
Do smooth muscle have thick and thin filament?
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, andthick 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.
If a muscle is already at about 80 of its resting length it cannot be stimulated to contract any more because?
the Z lines abut against the thick filaments and cannot go any further
What is cardiac smooth muscle?
There is nothing really called 'cardiac smooth muscle'. Cardiac muscle is striated like skeletal muscle but it is not under your control like skeletal muscle is. It acts more like smooth muscle because of this reason. But we only use the terms smooth muscle, striated (skeletal) muscle or cardiac muscle.
What layer of an artery consists mostly of smooth muscle?
Arterial walls are more muscular than the walls of veins. This muscle is smooth involuntary muscle.
Do intestines and bladder have one or more layers of smooth muscle?
yes
What has more muscle the aortic semilunar valve or the aorta?
The valve in itself has no muscle, but the entire aorta is lined with a smooth muscle. The answer: aorta
What type of muscle is found in the walls of hollow organs and in the walls of blood vessels?
multiunit smooth muscle are found in those areas and a few more.
What is the difference between the smooth and striated muscle?
The difference is that the strained muscle has more tension on it and the smooth muscle doesn't like if you break your leg you relay on the other leg to get you around so while the muscle fixes you should use the other arm.
What organ is not made of smooth muscle?
The brain, the heart, the lungs, the liver, the gall bladder, the kidneys, the pancreas, the testes, the ovaries, the eyes, and probably more are not made from smooth muscle. The heart. It is made of cardiac muscle fibers.
Where is one smooth muscle cell?
in the heart because smoothe muscle cells have more endurance than other types
What are the two contractile proteins that make up the myofilaments of skeletal muscle?
amuscle cell is made up of two kinds of protein filaments called actin and myosin
