Guidelines

What type of contraction does smooth muscle make?

What type of contraction does smooth muscle make?

Smooth muscle may contract phasically with rapid contraction and relaxation, or tonically with slow and sustained contraction. The reproductive, digestive, respiratory, and urinary tracts, skin, eye, and vasculature all contain this tonic muscle type.

What happens during smooth muscle contraction?

Smooth muscle cells also develop tonic and phasic contractions in response to changes in load or length. Regardless of the stimulus, smooth muscle cells use cross-bridge cycling between actin and myosin to develop force, and calcium ions (Ca2+) serve to initiate contraction.

What does myosin gene do?

The MYH11 gene provides instructions for making a protein called smooth muscle myosin heavy chain 11. It belongs to a group of proteins called myosins, which are involved in cell movement and the transport of materials within and between cells.

Does smooth muscle have powerful contractions?

Smooth muscle cells contain a single nucleus and lack sarcomeres. They specialize in slow, powerful contractions and are under involuntary control.

What hormone causes contraction of smooth muscle?

Smooth muscles are stimulated to contract by catecholamines released by nerves in the vicinity of the muscle, as well as by a number of other hormones. Smooth muscles are also stimulated by the catecholamines in the bloodstream that originate in the secretions of the adrenal medulla.

What controls contraction of cardiac muscle?

Cardiac muscle differs from skeletal muscle in that it exhibits rhythmic contractions and is not under voluntary control. The rhythmic contraction of cardiac muscle is regulated by the sinoatrial node of the heart, which serves as the heart’s pacemaker.

What is the role of tropomyosin in muscle contraction?

Tropomyosin blocks myosin binding sites on actin molecules, preventing cross-bridge formation, which prevents contraction in a muscle without nervous input. The protein complex troponin binds to tropomyosin, helping to position it on the actin molecule.

How is myosin regulated?

Smooth muscle myosin is regulated by phosphorylation of one of the two myosin light chains. This phosphorylation causes an unfolding of the myosin that allows it to interact with actin to produce force. Smooth muscle myosin has a large movement of its light chain binding domain that is coupled to ADP release.

What causes contraction of smooth muscle?

Smooth muscle contraction is initiated when the Ca++ binds to intracellular calmodulin, which then activates an enzyme called myosin kinase that phosphorylates myosin heads so they can form the cross-bridges with actin and then pull on the thin filaments.

How is cardiac contraction initiated?

Cardiac contraction is the end result of action potentials that are initiated at the sinoatrial node by the spontaneous depolarization of the nodal cells to threshold and the subsequent transmission of triggered action potentials in different cells of the cardiac conduction pathway to the atrial and ventricular muscle …

What are the four properties of cardiac muscle?

Four characteristics define cardiac muscle tissue cells: they are involuntary and intrinsically controlled, striated, branched, and single nucleated.

What is the function of the MYH11 gene?

The MYH11 gene provides instructions for making a protein called smooth muscle myosin heavy chain 11. It belongs to a group of proteins called myosins, which are involved in cell movement and the transport of materials within and between cells.

What are the effects of repeated coils of MYH11?

The repeated coiled coil of MYH11 may result in dimerization of the CBFB fusion protein, which in turn would lead to alterations in transcriptional regulation and contribute to leukemic transformation.

What is the role of myosin in muscle contraction?

Thick filaments made of myosin, along with thin filaments of another protein called actin, are the primary components of muscle fibers and are important for muscle tensing (contraction). Smooth muscle myosin heavy chain 11 forms part of a myosin protein complex found in smooth muscles.

What kind of muscle is myosin heavy chain 11?

Huang et al. (2004), who referred to MYH11 as smooth muscle myosin heavy chain (SMMHC), investigated the molecular basis for the dominant inactivation of RUNX1 ( 151385) by the leukemogenic inversion of chromosome 16.