Blood pressure (BP) is the pressure exerted by blood on the walls of a blood vessel that helps to push blood through the body. Systolic blood pressure measures the amount of pressure that blood exerts on vessels while the heart is beating. The optimal systolic blood pressure is 120 mmHg. Diastolic blood pressure measures the pressure in the vessels between heartbeats. The optimal diastolic blood pressure is 80 mmHg. Many factors can affect blood pressure, such as hormones, stress, exercise, eating, sitting, and standing. Blood flow through the body is regulated by the size of blood vessels, by the action of smooth muscle, by one-way valves, and by the fluid pressure of the blood itself.

Complete the tasks on the list below:

• Read the following page in the OpenStax textbook
• Blood Flow and Blood Pressure Regulation
• On this page you can skim down to the section titled, The Mechanics of Human Breathing - then skim the rest of the page
• Watch the CIRCULATION video 
• Use the Glossary at the bottom of the page to help with the vocabulary for this week
• Use the Review Questions and Free Response questions to check for understanding

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