【单选题】A 42-year-old man with myasthenia gravis notes increased muscle strength when he is treated with an acetylcholinesterase (ACHE) inhibitor. The basis for his improvement is increased
A.
amount of acetylcholine (Ach) released from motor nerves
B.
levels of Ach at the muscle end plates
C.
number of Ach receptors on the muscle end plates
D.
amount of norepinephrine released from motor nerves
E.
synthesis of norepinephrine in motor nerves
【判断题】Hypertropy refers to the increased size of a muscle.
【单选题】Contractions called _____ occur whenever the forces applied to a muscle are increased, but the muscle does not appear to be moving.
D.
summation contractions
【单选题】The amount of force produced by a skeletal muscle can be increased by
A.
Increasing extracellular Mg 2+
B.
Decreasing extracellular Ca 2+
C.
Increasing the activity of acetylcholine esterase
D.
Decreasing the interval between contractions
E.
Increasing the preload beyond 2.2 µm
【简答题】题9一19图所示两个相同的圆柱体,质量m=6.35kg,半径r=127mm,绳子连接如图所示。当t=0时将系统由静止释放。 试求: (1)在t=3s时圆柱体B的中心速度; (2)两个圆柱间绳子的拉力。
【判断题】Increased afferent impulses of tendon organs will inhibit alpha motor neurons in the same muscle.
【简答题】如图所示,立方体的每个面上都有一个自然数,已知相对的两个面上两数之和都相等,如果19、9、7的对面的数分别是a、b、c,试求 a 2 +b 2 +c 2 -ab-bc-ca之值。
【单选题】如图9-30所示的MAN-B&W-S-MC/MCE主机操作系统中,管19的信号表示____。
【单选题】塑料吸盘是家庭常用的小工具,小明做了如图 9-3-19 所示的实验,在实验中吸盘都保持静止,所挂钩码已是吸盘所能提起的最大物重,你认为下列说法中正确的是( )
A.
图甲中如果将塑料吸盘戳个小孔,吸盘仍能吸在墙面上
D.
利用图乙所示的实验在海拔更高的地区仍能提起该重物
【单选题】如图19所示,编号为甲的房间应铺设几块预制板( )。