The force of contraction of cardiac muscle is typically increased by:
A. increased Ca++ extrusion by the Na+-Ca++ antiporter in cardiac muscle
B. an increase in myosin phosphorylation in cardiac muscle
C. a decrease in cytosolic [Ca++] in the cardiac muscle
D. ?-adrenergic stimulation of the cardiac muscle
E. recruiting more cardiac muscle cells
ANS: D
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Which of the following is NOT true of the knee joint?
A. The knee is a modified hinge joint. B. The knee contains a lateral meniscus and a medial meniscus. C. The ACL (anterior cruciate ligament) is positioned so that it helps prevent hyperextension of the knee. D. It contains a condylar joint between the patellar surface of the femur and the patella. E. All of these are true of the knee joint.
The phrenic nerves arise from the
A. cervical plexuses. B. sacral plexuses. C. brachial plexuses. D. lumbar plexuses.
Which of the following is true of joints that are first-class levers?
A. The fulcrum is at the opposite end from the tendinous attachment. B. Their output force is always greater than the input force. C. Their mechanical advantage is always less than 1.0. D. Their resistance is between the fulcrum and the distal end of the bone. E. The fulcrum is in the middle.
Which of the following statements about oxytocin is TRUE?
A. Target cells of oxytocin have receptors for the hormone in their nucleus. B. Oxytocin is synthesized in the hypothalamus. C. Oxytocin is secreted by the anterior pituitary gland. D. Oxytocin's main function is to increase the rate of respiration. E. Oxytocin keeps uterine smooth muscle from contracting, so it prolongs pregnancy.