问题 问答题 简答题

心肌细胞为什么不会产生强直收缩?

答案

参考答案:

心肌兴奋性周期变化的特点是有效不应期特别长,相当于整收缩期加舒张早期。在此期间,任何强度的刺激都不能引起心肌收缩。所以,每次收缩后必有舒张,使心脏始终保持收缩与舒张相互交替的节律性活动,不会产生类似于骨骼肌的强直收缩。

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                                                  Safety and Security Procedures

     Your safety and the security of your personal property are of the primary concern to those of us

who welcome you as our guest. We urge you to take advantage of the following suggestions.

     YOUR VEHICLE(交通工具)

     Lock it and don't leave money or valuable items inside. We are not responsible for their loss.

    TRAVELING

     Be good at noticing things around you when sightseeing or traveling. Stay in well-lit and heavily

traveled areas. Don't display large amounts of cash.

     GUEST ROOM SECURITY

     For additional security use the deadbolt (插锁) provided on your door and make sure the windows

are locked. As an additional precautious measure, please secure the secondary locks provided. Do not

admit anyone to your room without first making identification(身份鉴定). A one-way viewer is provided

in your door to assist with identification. If there is any doubt about the person's identity, please contact

the Front Desk.

      SAFETY BOXES

      Do not leave money or valuables in your room or vehicle. We provide free safety boxes for your

use. Hotel is not responsible for items left in the room valued over $200.

      KEYS

      Safeguard your key. Please do not leave it in the door. Do not give your key to others or leave it

unattended. Please leave your key at the Front Desk when you check out.

     REPORTING

     Please report any suspicious activity, or safety concerns to management.

     FIRE

     Please familiarize yourself with the nearest fire exits. Report fire or smoke to the hotel guard. In the

unlikely event of a fire, please move quickly and calmly to the nearest safe exit and leave the building.

     Avoid the use of elevator.

1. The suggestions are most probably from ______. 

A. a hotel manager      

B. a police officer    

C. an experienced traveler    

D. a tour guide

2. Which of the following is TRUE?

A. It is advised to travel to places where there are few people.

B. The hotel is not responsible for anything you lose.

C. Don't report to the manager unless you are sure something is going wrong.

D. You'd better use the deadbolt and the secondary locks for safety.

3. If you feel doubtful about a stranger who knocks at the door, you should _____.

A. let the person in after you have got his/her name  

B. open the door to check the person's ID card

C. call the Front Desk to make sure                

D. contact the local police for assistance