A myofibril is the
A. cell membrane of a muscle fiber.
B. cytoplasm of muscle cells.
C. structural and functional unit of the skeletal muscle cell.
D. contractile thread that extends the length of the muscle fiber.
E. protein strand composed of actin.
D
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Elbow extension takes place in what plane?
A. sagittal B. frontal C. transverse D. longitudinal
The superior nasal concha is a part of which bone?
A) vomer B) ethmoid C) sphenoid D) maxilla
Which of the following statements concerning pulmonary surfactant is incorrect?
a. It is secreted by Type II alveolar cells. b. It is deficient in newborn respiratory distress syndrome. c. It promotes elastic recoil of the lungs. d. It reduces the cohesive force between water molecules. e. It reduces surface tension.
Prolactin is secreted from the ________ gland, and its levels ________ during pregnancy.
A. corpus luteum; increase tenfold B. anterior pituitary; increase tenfold C. hypothalamus; double D. mammary; double