Describe the role calcium has in the contraction of the sarcomere in skeletal and smooth muscle tissues
What will be an ideal response?
Calcium is the link between excitation and contraction. In skeletal muscle, calcium is released from the sarcoplasmic reticulum upon stimulation from action potentials passing down the transverse tubules. The calcium binds to troponin, causing a conformational change. As troponin changes shape it causes tropomyosin to change its shape, physically moving out of its blocking position. Myosin cross-bridge can now attach to the exposed actin binding sites. The binding triggers the cross-bridge to bend and the power stroke occurs. In smooth muscle, upon stimulation, calcium moves from the ECF into the cytosol. Calcium binds to calmodulin, which in turn activates myosin light chain kinase. This enzyme phosphorylates a myosin cross-bridge, which can now bind with actin.
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Solutions are formed with water and ________ molecules as solutes which dissolve in them.
Fill in the blank(s) with the appropriate word(s).
A 19-year-old young woman with a long history of irritable bowel syndrome presents for the possibility of surgical resection of the gastrointestinal (GI) tract where the vagal parasympathetic innervation terminates. Which of the following sites is most appropriate for surgical resection?
(A) Duodenojejunal junction (B) Ileocecal junction (C) Right colic flexure (D) Left colic flexure (E) Anorectal junction
_____ refers to the traditional ideas and values passed down from generation to generation within a group and transmitted to members of the group by symbols.
A. Civilization B. Culture C. Evolution D. Development
In the following illustration, the arrow points to the:
A) left vagus nerve. B) left sympathetic trunk. C) left phrenic nerve. D) left internal thoracic artery. E) hemiazygos vein.