RespCircQuizReview

When your heart and breathing speed up or slow down, your body is trying to

• decrease lung volume.

• bring in more carbon dioxide.

• increase its red blood cells.

• maintain homeostasis.

In the lungs, oxygen diffuses into the blood from the

• aorta.

• trachea.

• bronchioles.

• alveoli.

Why is it difficult for your body to return blood from your feet when you sit for too long?

• Blood has to travel a greater distance.

• Skeletal muscles are not squeezing the veins.

• Gravity makes the blood flow backward.

• The heart does not beat fast enough at rest.

What determines whether molecules diffuse into or out of the blood?

• the number of capillaries the blood flows through

• the surface protein markers that indicate blood type

• the ratio of red blood cells to white blood cells

• the concentration of molecules (O2 or CO2) dissolved in blood.

Materials can diffuse into and out of blood in the capillaries because the capillary

• beds are near the heart.

• fibers are very elastic.

• walls are very thin.

• muscles act as pumps.

In addition to carrying O2 to body’s cells, red blood cells

• pick up CO2 from the cells.

• carry excess water to the cells.

• attack pathogens inside the body.

• help form clots to control bleeding.

Which parts of the circulatory system deliver oxygen-rich blood to the rest of the body in the systemic circulation circuit?

• the left ventrical and the pulmonary artery

• the left atrium and the capillaries

• the atria and the pulmonary artery

• the left ventrical and the aorta

Pulmonary circulation occurs only between the heart and the

• organs.

• lungs.

• brain.

• limbs.

A pulmonary vein differs from most veins in that it carries

• twice as much blood.

• its own blood supply.

• oxygen-rich blood.

• more carbon dioxide

A clear, pale-yellow fluid that makes up more than half of the blood is known as

• plasma.

• platelets.

• white blood cells.

• red blood cells.