Which of the following is not characteristic of smooth muscle? A) The striations are due to the orderly arrangement of actin and
myosin. B) Neurons that innervate smooth muscles are under involuntary control. C) Smooth muscle cells are uninucleate. D) Smooth muscles do not contain sarcomeres. E) The thin filaments of smooth muscle fibers are attached to dense bodies.
A) The striations are due to the orderly arrangement of actin and myosin
Explanation:
Smooth muscles are non-striated involuntary muscles which are found in the walls of stomach, urinary bladder, blood vessels...Smooth muscle tissue is composed of spindle-shaped muscle cells with single central nucleus. Like the other two type of muscles (cardiac and skeletal), smooth muscles also have four main functions:
Contractility-ability to contract. In the case of skeletal muscles it is voluntary, while in cardiac and smooth muscles it is unconscious.
Excitability-ability to change membrane potential usually by the influence of nervous impulse.
Extensibility-the capacity to lengthen
Elasticity-ability to change its length and then return to previous.
It is possible to produce an offspring from a zebra mating with a donkey. Indeed, in Florence, Italy, a male zebra mated with a female donkey and produced a striped mule.
