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【单选题】
我国重轨用钢U71Mn(平均含碳量0.71%)的退火态组织主要为:A.
铁素体
B.
珠光体
C.
奥氏体
D.
莱氏体
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皮皮学刷刷变学霸
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【简答题】a___ an abnormal rate of muscle contractions in the heart
【单选题】High concentrations of H2S gas are most dangerous to personnel because they can ______.
A.
cause involuntary muscle contractions
B.
paralyze your breathing system
C.
cause eye inflammation
D.
cause dizziness
【单选题】________ acts on the smooth muscle of the uterus and mammary glands, causing uterine contractions during labor and promoting milk release during lactation.
A.
Vasopressin
B.
Oxytocin
C.
Prostaglandin H 2
D.
Growth hormone
【单选题】What is mainly responsible for the delay between the atrial and ventricular contractions?
A.
the shallow slope of AV node pacemaker potentials
B.
slow action potential conduction velocity of AV node cells
C.
slow action potential conduction velocity along atrial muscle cell membranes
D.
slow action potential conduction in the Purkinje network of the ventricles
E.
greater parasympathetic nerve firing to the ventricles than to the atria
【判断题】Cardiac muscle cannot undergo summation of contractions because it has a very long refractory period.
A.
正确
B.
错误
【单选题】患者女性,宫内妊娠38周,G1P0,宫缩强,胎儿在宫缩期迅速娩出,胎儿体重4100g,总产程为3小时40分钟。产后有较多的持续性阴道流血,色鲜红,能凝固,出血原因最可能是
A.
胎盘剥离不全
B.
胎盘植入
C.
产后宫缩乏力
D.
凝血功能障碍
E.
软产道损伤
【单选题】________ is a central nervous system disease which causes severe muscle contractions.
A.
Tetanus
B.
Ulcer
C.
Cataract
D.
Glaucoma
【简答题】Muscle contractions called hypnic myoclonia are often preceded by a sensation of starting to fall. (para.4)
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