1 Go to the Tools menu and select Export. 2  Name the file. 3  Examples might be: AddressBook-Thunderbird or ListName-Thunderbird and choose to save it to your Desktop. 4  Change the format to: Comma Separated. 5  Click the Save button. 6  Log into gmail.rider.edu and navigate to Contacts. Go to the Tools menu and select Export. 2  Name the file. 3  Examples might be: AddressBook-Thunderbird or ListName-Thunderbird and choose to save it to your Desktop. 4  Change the format to: Comma Separated. 5  Click the Save button. 6  Log into gmail.rider.edu and navigate to Contacts.
Full Answer. In addition to two upper chambers, the heart also has two lower chambers. The lower chambers are known as the left and right ventricles, which have a primary responsibility of pumping blood out of the heart. Separating the upper and lower chambers are different valves, which control the direction and rate of blood flow. A complete circulating cycle is defined as each instance the two atria bring in blood and the ventricles pump out blood.
The upper chambers are called the left atrium and the right atrium-the plural of atrium is atria. The two lower chambers are the the left ventricle and the right ventricle. When the two upper chambers-the atria-contract at an excessively high rate, and in an irregular way, the patient has atrial fibrillation.