1. Histologically, skeletal muscle often said to be arranged or structured in a
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Question
1. Histologically, skeletal muscle often said to be arranged or structured in a hierarchy fashion. Explain what is meant by this 2. Explain how piloerection works. Be sure that you invoke how muscle (what type of muscle?) and sensory activation are involved at the molecular level. 3. Rigor mortis is when the muscles stiffen after death. In humans, rigor mortis occurs several hours after death and lasts for about 12 hours. Explain why the muscles stiffen followed by complete flaccidness after rigor mortis wears off, Frame your answer in terms of the molecular mechanism.Explanation / Answer
1. Skeletal muscle constitutes the muscle which is attached to skeleton and controls motor movements and posture. Cells are multinucleated syncytium formed by fusion of individual small muscle cells or myoblasts during development. They are filled with longitudinally arrayed subunits called myofibrils which are made up of myofilaments myosin and actin.
Skeletal muscle fibers bear stritations and have many peripherally located nuclei and are of same thickness throughout their length.
2. Protection is caused by the stimulus of cold surroundings which is caused the tiny muscles attached to each hair follicle to contract. Due to this contractions, the hair strands stand straight . Each contracting muscle creates a shallow depression on skin surface which cause surrounding area to protrude.
Piloerection is causes by cobtraction of arrector pili muscle. It is a tiny muscle in skin attached to hair follicle. Sympathetic post ganglion neurons inmervetae blood vessels, piloerector muscles and sweat glands as well as other target organs or tissues in the body. It there by activates sensory neurons on skin cells and leads to activation of hair cells to stand straight.
3. Rigor mortis is stiffening of body after death due to loss of Adenosine triphosphate from the muscles of the body. Muscle stiffen due to coagulation of muscle protein or a shift in muscle energy containers.
Following death, the muscles become initially falcid and the lower jaw and extremities can be passively moved. Rigor mortis effects all muscle in body, both smooth and skeletal.
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