Human Biology Ch:7

• Which of the following statements about the circulatory system is false?

  Blood in the pulmonary vein is deoxygenated.
• Varicose veins are often prominent on the legs. Why do you think this is the case?

  Blood in the legs is farthest away from the heart and has to flow up to reach it.
• Blood flow that is directed through the lungs and back to the heart is called _________ ________.

  Pulmonary circulation
• White blood cells:

  Can be classified as granulocytes or agranulocytes, defend the body against bacteria and viruses, also called leucocytes.
• Platelet plug formation occurs at which point?

  When platelets are attracted to a site of blood vessel damage.
• In humans, the plasma comprises what percentage of the blood?

  55%
• The heart's internal pacemaker beats by:

  The excitation of cardiac muscle cells at the sinoatrial node is followed by the atrioventricular node.
• During the systolic phase of the cardiac cycle, the heart is_______.

  contracting
• Cardiomyocytes are similar to skeletal muscle because:

  That are striated
• How do arteries differ from veins?

  Arteries carry blood away from the heart, while veins carry blood towards the heart.
• High blood pressure would be a result of____________.

  A high cardiac output and high peripheral resistance.