Epinephrine increases the force of contraction of cardiac muscle by:
A. increasing the amount of Ca++ in the SR for release to the cytosol
B. increasing the level of myosin light-chain phosphorylation
C. inhibiting the ryanodine receptor
D. increasing Ca++ extrusion through the sarcolemmal Ca++ pump
E. shortening the duration of the action potential
ANS: A
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The designation Ca2+ means
A) calcium has gained two more electrons. B) calcium has gained two more protons. C) calcium has space for two more protons. D) calcium has space for two more electrons.
During weeks 9-12 of fetal development, ________:
a. bone marrow begins to assume erythrocyte production b. meconium begins to accumulate in the intestines c. surfactant production begins in the fetal lungs d. the spinal cord begins to be myelinated
What muscular changes are involved in the breathing process?
What will be an ideal response?
Label C represents the
A) pulmonary trunk. B) ascending aorta. C) right pulmonary arteries. D) right pulmonary veins. E) superior vena cava.